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Nuclear three dimensional (3D) folding of chromatin structure has been linked to gene expression regulation and correct developmental programs, but little is known about the 3D architecture of sex chromosomes within the nucleus, and how that impacts their role in sex determination. Here, we determine the sex-specific 3D organization of the model brown alga Ectocarpus chromosomes at 2 kb resolution, by mapping long-range chromosomal interactions using Hi-C coupled with Oxford Nanopore long reads. We report that Ectocarpus interphase chromatin exhibits a non-Rabl conformation, with strong contacts among telomeres and among centromeres, which feature centromere-specific LTR retrotransposons. The Ectocarpus chromosomes do not contain large local interactive domains that resemble TADs described in animals, but their 3D genome organization is largely shaped by post-translational modifications of histone proteins. We show that the sex determining region (SDR) within the U and V chromosomes are insulated and span the centromeres and we link sex-specific chromatin dynamics and gene expression levels to the 3D chromatin structure of the U and V chromosomes. Finally, we uncover the unique conformation of a large genomic region on chromosome 6 harboring an endogenous viral element, providing insights regarding the impact of a latent giant dsDNA virus on the host genome's 3D chromosomal folding. The 3D chromatin organisation of sex chromosomes within the nucleus remains elusive. This study determines the chromatin architecture of the brown alga Ectocarpus, linking sex-specific chromatin dynamics, histone modification and gene expression to the 3D structure of the U and V sex chromosomes. [ABSTRACT FROM AUTHOR]

The factors contributing to evolution of androdioecy, the coexistence of hermaphrodites and males such as in Caenorhabditis elegans, remains poorly known. However, nematodes exhibit androdioecy in at last 13 genera with the predatory genus Pristionchus having seven independent transitions towards androdioecy. Nonetheless, associated genomic architecture and sex determination mechanisms are largely known from Caenorhabditis. Here, studying 47 Pristionchus species, we observed repeated chromosome evolution which abolished the ancestral XX/XO sex chromosome system. Two phylogenetically unrelated androdioecious Pristionchus species have no genomic differences between sexes and mating hermaphrodites with males resulted in hermaphroditic offspring only. We demonstrate that stochastic sex determination is influenced by temperature in P. mayeri and P. entomophagus, and CRISPR engineering indicated a conserved role of the transcription factor TRA-1 in P. mayeri. Chromosome-level genome assemblies and subsequent genomic analysis of related Pristionchus species revealed stochastic sex determination to be derived from XY sex chromosome systems through sex chromosome-autosome fusions. Thus, rapid karyotype evolution, sex chromosome evolution and evolvable sex determination mechanisms are general features of this genus, and represent a dynamic background against which androdioecy has evolved recurrently. Future studies might indicate that stochastic sex determination is more common than currently appreciated. Sexual systems evolve frequently in nematodes. Through large-scale genomic analyses, Yoshida et al. find rapid chromosome evolution, sex chromosome turnover and acquisition of stochastic sex determination, are involved in sexual system evolution of Pristionchus nematodes. [ABSTRACT FROM AUTHOR]

Life history is defined by traits that reflect key components of fitness, especially those relating to reproduction and survival. Research in life history seeks to unravel the relationships among these traits and understand how life history strategies evolve to maximize fitness. As such, life history research integrates the study of the genetic and developmental mechanisms underlying trait determination with the evolutionary and ecological context of Darwinian fitness. As a leading model organism for molecular and developmental genetics, Caenorhabditis elegans is unmatched in the characterization of life history-related processes, including developmental timing and plasticity, reproductive behaviors, sex determination, stress tolerance, and aging. Building on recent studies of natural populations and ecology, the combination of C. elegans ' historical research strengths with new insights into trait variation now positions it as a uniquely valuable model for life history research. In this review, we summarize the contributions of C. elegans and related species to life history and its evolution. We begin by reviewing the key characteristics of C. elegans life history, with an emphasis on its distinctive reproductive strategies and notable life cycle plasticity. Next, we explore intraspecific variation in life history traits and its underlying genetic architecture. Finally, we provide an overview of how C. elegans has guided research on major life history transitions both within the genus Caenorhabditis and across the broader phylum Nematoda. While C. elegans is relatively new to life history research, significant progress has been made by leveraging its distinctive biological traits, establishing it as a highly cross-disciplinary system for life history studies. [ABSTRACT FROM AUTHOR]

Sexual selection drives rapid evolution of morphological, physiological, and behavioral traits, especially in males, and it may also drive the rapid evolution of hybrid male sterility. Indeed, the faster male theory of speciation was once viewed as a major cause of Haldane's rule in male-heterogametic XY taxa, but is increasingly being replaced by the genetic conflict hypothesis partly because it cannot explain the faster evolution of hybrid female sterility in female-heterogametic ZW taxa. The theory nonetheless predicts that there should be more genes for hybrid male sterility than for hybrid female sterility even in such taxa, but this remains untested. Thus, finding evidence for the faster male theory of reproductive isolation beyond the F1 generation in ZW systems still represents a challenge to studying the impact of sexual selection. In this study, we examined F2 hybrids between the domesticated silkworm Bombyx mori and the wild silk moth Bombyx mandarina , which have ZW sex determination. We found that although only females showed reduced fertility in the F1 generation, the F2 hybrid males had a significant reduction in fertility compared with the parental and F1 males. Importantly, 27% of the F2 males and 15% of the F2 females were completely sterile, suggesting the presence of recessive incompatibilities causing male sterility in female-heterogametic taxa. [ABSTRACT FROM AUTHOR]

Aim: Sex‐determining region Y‐related high‐mobility group box 4 (SOX4) has been reported to play a carcinogenic role in endometrial cancer (EC). However, the biological function and regulatory mechanisms of SOX4 in ferroptosis during the progression of EC are still unknown. Methods: The mRNA and protein levels were scrutinized by quantitative reverse‐transcription polymerase chain reaction and western blot, respectively. The cell viability and proliferative capability were determined by cell counting kit‐8 assay and 5‐ethynyl‐2′‐deoxyuridine (EdU) assay. Transcriptional regulation of gene expression was investigated by dual‐luciferase reporter assay and chromatin immunoprecipitation. Ferroptosis was evaluated by detection of reactive oxygen species, malondialdehyde, Fe2+, and ferroptosis‐related proteins. The mice test was implemented to confirm the influence of SOX4 on EC tumor growth and ferroptosis in vivo. Results: We here discovered the elevation of SOX4 in EC tissues and cells. Functionally, SOX4 knockdown hampered proliferation and promoted ferroptosis of EC cells. Mechanistically, SOX4 bound to p53 promoter and inhibited its transcriptional activity in EC cells. In addition, p53 transcriptionally suppressed SLC7A11 expression in EC cells. Downregulation of p53 reverses the effect of SOX4 knockdown on proliferation and ferroptosis of EC cells. Finally, in vivo experiments demonstrated that SOX4 depletion hindered tumor growth and triggered ferroptosis in EC. Conclusions: These findings collectively suggested that SOX4 inhibited ferroptosis and promoted proliferation of EC cells via the p53/SLC7A11 signaling. Our research unveiled a novel regulatory mechanism of ferroptosis in EC, offering promising perspectives for the development of EC therapies. [ABSTRACT FROM AUTHOR]

The skeleton in question derives from the Late Iron Age monument of Nor Armavir and was unearthed from burial No. 19. The deceased was buried in an unusual position. In this article, we characterise the pathological bony changes indicative of tuberculous spondylitis. The skeleton was subject to a detailed macroscopic investigation. Besides age at death estimation and sex determination, a careful palaeopathological evaluation was performed on the bone remains. In addition, volumetric (3D) computed tomography was carried out on four lumbar vertebrae (L2--5) to complement the macromorphology-based diagnosis. [ABSTRACT FROM AUTHOR]

The presence or absence of amino acid (aa) polymorphisms between Csd protein variants determine sex in honeybees. The polymorphic site differences between protein variants are recognized by selective binding, which activates the heteromeric protein complex or inactivates the homomeric protein complex to determine sexual development. The primary signal of the csd (complementary sex determiner) gene is transferred to the feminizer (fem) gene, in which alternative sexual splicing turns Fem protein activity on in females and off in males. This sexual decision is amplified cell autonomously by a positive regulatory feedback loop and transduced to sex-specific regulated transcription factor genes that realize sexual development. The complementary mechanism evolved via gene duplication followed by neofunctionalization. Few aa changes in distinct functional elements were required for the origin of this new complementary mechanism. The cause of this parsimonious evolution was the preexistence of other aas in favorable constellations in the progenitor sequences. Complementary sex determination regulates female and male development in honeybees (Apis mellifera) via heterozygous versus homo-/hemizygous genotypes of the csd (complementary sex determiner) gene involving numerous naturally occurring alleles. This lineage-specific function offers a rare opportunity to understand an undescribed regulatory mechanism and the molecular evolutionary path leading to this mechanism. We reviewed recent advances in understanding how Csd recognizes different versus identical protein variants, how these variants regulate downstream pathways and sexual differentiation, and how this mechanism has evolved and been shaped by evolutionary forces. Finally, we highlighted the shared regulatory principles of sex determination despite the diversity of primary signals and demonstrated that lineage-specific mutations are very informative for characterizing newly evolved functions. [ABSTRACT FROM AUTHOR]

In the field of forensic anthropology, researchers aim to identify anonymous human remains and determine the cause and circumstances of death from skeletonized human remains. Sex determination is a fundamental step of this procedure because it influences the estimation of other traits, such as age and stature. Pelvic bones are especially dimorphic, and are thus the most useful bones for sex identification. Sex estimation methods are usually based on morphologic traits, measurements, or landmarks on the bones. However, these methods are time-consuming and can be subject to inter- or intra-observer bias. Sex determination can be done using dry bones or CT scans. Recently, artificial neural networks (ANN) have attracted attention in forensic anthropology. Here we tested a fully automated and data-driven machine learning method for sex estimation using CT-scan reconstructions of coxal bones. We studied 580 CT scans of living individuals. Sex was predicted by two networks trained on an independent sample: a disentangled variational auto-encoder (DVAE) alone, and the same DVAE associated with another classifier (Crecon). The DVAE alone exhibited an accuracy of 97.9%, and the DVAE + Crecon showed an accuracy of 99.8%. Sensibility and precision were also high for both sexes. These results are better than those reported from previous studies. These data-driven algorithms are easy to implement, since the pre-processing step is also entirely automatic. Fully automated methods save time, as it only takes a few minutes to pre-process the images and predict sex, and does not require strong experience in forensic anthropology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chromosome level female and male genomes of golden pompano were assembled. • Both genomes are conserved and no highly differentiated sex chromosomes occur. • A 3.5 Mb sex-determining region on LG15 was identified based on QTL mapping. • Hsd17b1 , Micall2 and Lmx1a were identified as candidates for sex determination. • Three SNP loci and one gene gpsstr1 were significantly linked to growth traits. • Loss of sstr1a (homologue of gpsstr1) in zebrafish caused growth retardation. Golden pompano (Trachinotus ovatus) is economically significant important for offshore cage aquaculture in China and Southeast Asian countries. Lack of high-quality genomic data and accurate gene annotations greatly restricts its genetic breeding progress. To decode the mechanisms of sex determination and rapid growth in golden pompano and facilitate the sex- and growth-aimed genetic breeding. Genome assemblies of male and female golden pompano were generated using Illumina, PacBio, BioNano, genetic maps and Hi-C sequencing data. Genomic comparisons, whole genome re-sequencing of 202 F1 individuals, QTL mapping and gonadal transcriptomes were used to analyze the sex determining region, sex chromosome evolution, SNP loci, and growth candidate genes. Zebrafish model was used to investigate the functions of growth candidate gene. Female (644.45 Mb) and male (652.12 Mb) genomes of golden pompano were assembled and annotated at the chromosome level. Both genomes are highly conserved and no new or highly differentiated sex chromosomes occur. A 3.5 Mb sex determining region on LG15 was identified, where Hsd17b1 , Micall2 and Lmx1a were putative candidates for sex determination. Three SNP loci significantly linked to growth were pinpointed, and a growth-linked gene gpsstr1 was identified by locus BSNP1369 (G → C, 17489695, Chr23). Loss of sstr1a (homologue of gpsstr1) in zebrafish caused growth retardation. This study provides insights into sex chromosome evolution, sex determination and rapid growth of golden pompano. [ABSTRACT FROM AUTHOR]

Pherosphaera fitzgeraldii , the Dwarf Mountain Pine, is a critically endangered conifer restricted to cliff ledges within waterfall spray zones in the Greater Blue Mountains Area of New South Wales, Australia. This species is under threat from pollution, invasive weeds, and limited recruitment, which are contributing to its declining population. Using a comprehensive conservation genomic approach, we assessed the population health of P. fitzgeraldii and developed strategic recommendations for its management. Genomic analysis of P. fitzgeraldii revealed the presence of two distinct genetic groups despite the limited distribution of the species. This genetic structure aligns with prevailing wind currents, indicating potential restrictions to pollen or seed exchange between subpopulations. Furthermore, limited gene flow was observed even among nearby subpopulations, emphasizing the risk of increased genetic differentiation due to ongoing isolation. Clonality is widespread in some subpopulations, and all subpopulations displayed signs of inbreeding and genetic depletion despite subdioecy, indicative of historical constraints on gene flow and small population sizes. We offer genomic-based recommendations for prioritizing conservation sites, enhancing genetic diversity in ex situ collections, and guiding future management. Further studies to uncover the sex determination mechanism of P. fitzgeraldii could help maintain balanced sex ratios in ex situ collections and support future genetic rescue efforts. This study underscores the value of genomics in informing protection and recovery of unique threatened species. [ABSTRACT FROM AUTHOR]

The swimming crab (Portunus trituberculatus) is an economically important species in China, and its growth traits show obvious sexual dimorphism. Thus, it is important to study the mechanism of sex determination and differentiation in this species. Herein, we identified 2138 differentially expressed genes and 132 differentially expressed long non-coding RNAs (lncRNAs) using Oxford Nanopore Technology full-length transcriptome sequencing. We predicted 561 target genes of the differentially expressed lncRNAs according to their location and base pair complimentary principles. Furthermore, pathways related to sex determination, differentiation, and reproduction were enriched for lncRNAs according to gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses. This indicated that lncRNAs might play regulatory roles in these pathways. Our results could form the basis for future studies of sex determination and differentiation in P. trituberculatus. [ABSTRACT FROM AUTHOR]

The editorial "Special Issue: Molecular Advance on Reproduction and Fertility of Aquatic Animals" explores the complexities of reproduction and fertility in commercial aquatic species, emphasizing the importance of sexual dimorphism and monosexual culture for aquaculture efficiency. The document delves into the molecular mechanisms of sex determination and gonadal development in aquatic animals, highlighting the role of genes, markers, and epigenetic modifications in sex differentiation. Additionally, it discusses the impact of environmental factors, such as food availability, on gonad maturation mechanisms, providing insights into adaptation strategies under starvation conditions. The research presented in this special issue contributes to a deeper understanding of reproduction and fertility in aquatic animals through advanced sequencing technologies and genetic analyses. [Extracted from the article]

In last 100 years or so, much information has been accumulated on avian karyology, genetics, physiology, biochemistry and evolution. The chicken genome project generated genomic resources used in comparative studies, elucidating fundamental evolutionary processes, much of it funded by the economic importance of domestic fowl (which are also excellent model species in many areas). Studying karyotypes and whole genome sequences revealed population processes, evolutionary biology, and genome function, uncovering the role of repetitive sequences, transposable elements and gene family expansion. Knowledge of the function of many genes and non-expressed or identified regulatory components is however still lacking. Birds (Aves) are diverse, have striking adaptations for flight, migration and survival and inhabit all continents most islands. They also have a unique karyotype with ~ 10 macrochromosomes and ~ 30 microchromosomes that are smaller than other reptiles. Classified into Palaeognathae and Neognathae they are evolutionarily close, and a subset of reptiles. Here we overview avian molecular cytogenetics with reptilian comparisons, shedding light on their karyotypes and genome structure features. We consider avian evolution, then avian (followed by reptilian) karyotypes and genomic features. We consider synteny disruptions, centromere repositioning, and repetitive elements before turning to comparative avian and reptilian genomics. In this context, we review comparative cytogenetics and genome mapping in birds as well as Z- and W-chromosomes and sex determination. Finally, we give examples of pivotal research areas in avian and reptilian cytogenomics, particularly physical mapping and map integration of sex chromosomal genes, comparative genomics of chicken, turkey and zebra finch, California condor cytogenomics as well as some peculiar cytogenetic and evolutionary examples. We conclude that comparative molecular studies and improving resources continually contribute to new approaches in population biology, developmental biology, physiology, disease ecology, systematics, evolution and phylogenetic systematics orientation. This also produces genetic mapping information for chromosomes active in rearrangements during the course of evolution. Further insights into mutation, selection and adaptation of vertebrate genomes will benefit from these studies including physical and online resources for the further elaboration of comparative genomics approaches for many fundamental biological questions. [ABSTRACT FROM AUTHOR]

ABSTRACT The early evolution of sex chromosomes has remained obscure for more than a century. The Vandiemenella viatica species group of morabine grasshoppers is highly suited for studying the early stages of sex chromosome divergence and degeneration of the Y chromosome. This stems from the fact that neo‐XY sex chromosomes have independently evolved multiple times by X‐autosome fusions with different autosomes. Here, we generated new chromosome‐level assemblies for two chromosomal races representing karyotypes with and without neo‐sex chromosomes (P24XY and P24X0), and sequence data of a third chromosomal race with a different neo‐XY chromosome system (P25XY). Interestingly, these two neo‐XY chromosomal races are formed by different X‐autosome fusions (involving chr1 and chrB, respectively), and we found that both neo‐Y chromosomes have partly ceased to recombine with their neo‐X counterpart. We show that the neo‐XY chromosomes have diverged through accumulation of SNPs and structural mutations, and that many neo‐Y‐linked genes have degenerated since recombination ceased. However, the non‐recombining regions of neo‐Y chromosomes host non‐degenerated genes crucial for sex determination, such as sex‐lethal and transformer, alongside genes associated with spermatogenesis, fertility, and reproduction, illustrating their integrative role as a masculinizing supergene. Contrary to expectations, the neo‐Y chromosomes showed (slightly) lower density of transposable elements (TEs) compared to other genomic regions. The study reveals the unique dynamics of young sex chromosomes, with evolution of recombination suppression and pronounced decay of (some) neo‐sex chromosome genes, and provides a compelling case illustrating how chromosomal fusions and post‐fusion mutational processes contribute to the evolution of supergenes. [ABSTRACT FROM AUTHOR]

Objectives: Chicken (Gallus gallus), as the most economically important poultry, is a classical and ideal model for studying the mechanism of vertebrate developmental biology and embryology. However, the sex determination and differentiation in chicken is still elusive, which limited the application and slowed down many basic studies in chicken. Data description: We applied PacBio Iso-seq to multiple spatiotemporal embryo-gonad tissues in the male and female chicken, which contain the blastoderm (E0, un-differentiation stage), genital ridge (E3.5–6.5, sex-differentiation stage) and gonads (E18.5, full-sex-differentiation stage). We obtained 51,479 and 48,356 full-length transcripts in male and female chicken embryo, respectively. The comprehensive annotated and evaluated these transcripts. The 1,293 and 1,556 candidate lncRNAs, 5,766 and 4,211 AS events in male and female. Collectively, our data constitutes a grand increase in the known number of lncRNA, AS (Alternative splicing) and Poly(A) during chicken embryo sex-differentiation and plays an important role in improving current genome annotation. In the meantime, the data will be enriched the functional studies in other birds. [ABSTRACT FROM AUTHOR]

Bird sex chromosomes play a unique role in sex-determination, and affect the sexual morphology and behavior of bird species. Core waterbirds, a major clade of birds, share the common characteristics of being sexually monomorphic and having lower levels of inter-sexual conflict, yet their sex chromosome evolution remains poorly understood. Here, by we analyse of a chromosome-level assembly of a female crested ibis (Nipponia nippon), a typical core waterbird. We identify neo-sex chromosomes resulting from fusion of microchromosomes with ancient sex chromosomes. These fusion events likely occurred following the divergence of Threskiornithidae and Ardeidae. The neo-W chromosome of the crested ibis exhibits the characteristics of slow degradation, which is reflected in its retention of abundant gametologous genes. Neo-W chromosome genes display an apparent ovary-biased gene expression, which is largely driven by genes that are retained on the crested ibis W chromosome but lost in other bird species. These results provide new insights into the evolutionary history and expression patterns for the sex chromosomes of bird species. The evolutionary trajectory of avian sex chromosomes may be more intricate than previously understood. In this study, sequencing and analysis of the neo-sex chromosomes and genome of the Crested Ibis suggests a multidirectional evolution of sex chromosomes in core waterbirds. [ABSTRACT FROM AUTHOR]

SOX9 is a key transcription factor for testis determination and development. Mutations in and around the SOX9 gene contribute to Differences/Disorders of Sex Development (DSD). However, a substantial proportion of DSD patients lack a definitive genetic diagnosis. SOX9 target genes are potentially DSD-causative genes, yet only a limited subset of these genes has been investigated during testis development. We hypothesize that SOX9 target genes play an integral role in testis development and could potentially be causative genes in DSD. In this study, we describe a novel testicular target gene of SOX9, Trpc3. Trpc3 exhibits high expression levels in the SOX9-expressing male Sertoli cells compared to female granulosa cells in mouse fetal gonads between embryonic day 11.5 (E11.5) and E13.5. In XY Sox9 knockout gonads, Trpc3 expression is markedly downregulated. Moreover, culture of E11.5 XY mouse gonads with TRPC3 inhibitor Pyr3 resulted in decreased germ cell numbers caused by reduced germ cell proliferation. Trpc3 is also expressed in endothelial cells and Pyr3-treated E11.5 XY mouse gonads showed a loss of the coelomic blood vessel due to increased apoptosis of endothelial cells. In the human testicular cell line NT2/D1, TRPC3 promotes cell proliferation and controls cell morphology, as observed by xCELLigence and HoloMonitor real-time analysis. In summary, our study suggests that SOX9 positively regulates Trpc3 in mouse testes and TRPC3 may mediate SOX9 function during Sertoli, germ and endothelial cell development. [ABSTRACT FROM AUTHOR]

The corrigendum published in the Frontiers in Cell & Developmental Biology on October 15, 2024, corrects errors in the author list and the inclusion of supplementary figures in the article titled "A role for TRPC3 in mammalian testis development." The corrected author list now includes Brittany Vining, and missing supplementary figures have been added to the publication. The corrigendum also addresses errors in the in-text citations and figure numbering, ensuring the accuracy of the scientific content presented in the original article. [Extracted from the article]

In many animals and flowering plants, sex determination occurs in the diploid phase of the life cycle with XX/XY or ZW/ZZ sex chromosomes. However, in early diverging plants and most macroalgae, sex is determined by female (U) or male (V) sex chromosomes in a haploid phase called the gametophyte. Once the U and V chromosomes unite at fertilization to produce a diploid sporophyte, sex determination no longer occurs, raising key questions about the fate of the U and V sex chromosomes in the sporophyte phase. Here, we investigate genetic and molecular interactions of the UV sex chromosomes in both the haploid and diploid phases of the brown alga Ectocarpus. We reveal extensive developmental regulation of sex chromosome genes across its life cycle and implicate the TALE-HD transcription factor OUROBOROS in suppressing sex determination in the diploid phase. Small RNAs may also play a role in the repression of a female sex-linked gene, and transition to the diploid sporophyte coincides with major reconfiguration of histone H3K79me2, suggesting a more intricate role for this histone mark in Ectocarpus development than previously appreciated. [ABSTRACT FROM AUTHOR]

Simple Summary: To obtain more female individuals in the breeding population of R. dybowskii, it is important to explore the sex determination mechanism based on whole genome analysis. In this study, we analyzed the genome survey of male individuals of R. dybowskii using next-generation sequencing technology. The estimated genome size of R. dybowskii was approximately 3585.05 M. The total size of contigs and scaffolds was 3,748,543,415 and 3,765,862,278 bp, respectively. The N50 length of contigs and scaffolds was 31,988 and 336,385,783, respectively. The Dmrt1 gene with an 18,893 bp length was obtained from the scaffolding genomes of R. dybowskii. Sequence alignment to Dmrt1 revealed that the two male-specific DNA markers (MSM-222 and MSM-261) were not located on Dmrt1. This indicated that Dmrt1 may not be the only key gene for sex determination in R. dybowskii. Rana dybowskii is one of the important aquaculture species in Northeast China. The fallopian tubes of female R. dybowskii are used to prepare oviductus ranae (an important traditional Chinese medicine). Therefore, R. dybowskii females have higher economical value than males. An increasing female R. dybowskii population can increase the benefits from R. dybowskii culture. However, the genome of amphibians is complex, making it difficult to investigate their sex determination mechanism. In this study, we analyzed the genome of male R. dybowskii using next-generation sequencing technology. A total of 200,046,452,400 bp of clean data were obtained, and the K-mer analysis indicated that the depth was 50×. The genome size of R. dybowskii was approximately 3585.05 M, with a heterozygosity rate, repeat sequence ratio, and genome GC content of 1.15%, 68.96%, and approximately 43.0%, respectively. In total, 270,785 contigs and 498 scaffolds were generated. The size of the contigs and scaffolds was 3,748,543,415 and 3,765,862,278 bp, respectively, with the N50 length of 31,988 and 336,385,783. The longest contig and scaffold were of the size 137,967,485 and 1,808,367,828 bp, respectively. The number of contigs and scaffolds > 10K nt was 99,620 and 451, respectively. Through annotation, 40,913 genes were obtained, including 156,609 CDS (i.e., 3.83 CDS per gene). Sequence alignment was performed with the assembled scaffolding genome in this study. Two and one fragment had high homology with two male-specific DNA molecular markers of R. dybowskii discovered previously (namely, MSM-222 and MSM-261, respectively). In addition, the Dmrt1 gene of R. dybowskii was obtained with a length of 18,893 bp by comparison and splicing. The forward primers amplifying MSM-222 and MSM-261 were located at 322–343 and 14,501–14,526 bp of Dmrt1, respectively. However, sequence alignment revealed that MSM-222 and MSM-261 were not located on Dmrt1, and only some homologous parts were observed. This indicated that in addition to Dmrt1, other important genes may play a crucial role in the sex determination mechanism of R. dybowskii. Our study provided a foundation for the subsequent high-quality genome construction and provided important genomic resources for future studies on R. dybowskii. [ABSTRACT FROM AUTHOR]

The Northern snakehead (Channa argus) is a significant economic aquaculture species in China. Exhibiting sexual dimorphism in the growth rate between females and males, mono-sex breeding holds substantial value for aquaculture. This study employed GWAS and transcriptome analysis were applied to identify sex determination genomic regions and develop sex-specific markers. A total of 270 single-nucleotide polymorphisms (SNPs) and 31 insertion-deletions (InDels) were identified as being sexually dimorphic through GWAS and fixation index (Fst) scanning. Based on GWAS results, two sex-specific InDel markers were developed, effectively distinguishing genetic sex for XX females, XY males, and YY super-males via (polymerase chain reaction) PCR amplification. A major genomic segment of approximately 115 kb on chromosome 3 (Chr 03) was identified as the sex-determination region. A comparative transcriptome analysis of gonads for three sexes identified 158 overlapping differentially expressed genes (DEGs). Additionally, three sex-related candidate genes were identified near the sex determination region, including id2, sox11, and rnf144a. Further studies are required to elucidate the functions of these genes. Overall, two sex-specific InDel markers support a male heterogametic XX/XY sex-determination system in Northern snakeheads and three candidate genes offer new insights into sex determination and the evolution of sex chromosomes in teleost fish. [ABSTRACT FROM AUTHOR]

Background: The blunt snout bream (Megalobrama amblycephala) is an important economic freshwater fish in China with tender flesh and high nutritional value. With the cultivation of superior new varieties and the expansion of breeding scale, it becomes imperative to employ sex-control technology to cultivate monosexual populations of M. amblycephala, thereby preventing the deterioration of desirable traits. The development of specific markers capable of accurately identifying the sex of M. amblycephala would facilitate the determination of the genetic sex of the breeding population before gonad maturation, thereby expediting the processes of sex-controlled breeding of M. amblycephala. Results: A whole-genome re-sequencing was performed for 116 females and 141 males M. amblycephala collected from nine populations. Seven candidate male-specific sequences were identified through comparative analysis of male and female genomes, which were further compared with the sequencing data of 257 individuals, and finally three male-specific sequences were generated. These three sequences were further validated by PCR amplification in 32 males and 32 females to confirm their potential as male-specific molecular markers for M. amblycephala. One of these markers showed potential applicability in M. pellegrini as well, enabling males to be identified using this specific molecular marker. Conclusions: The study provides a high-efficiency and cost-effective approach for the genetic sex identification in two species of Megalobrama. The developed markers in this study have great potential in facilitating sex-controlled breeding of M. amblycephala and M. pellegrini, while also contributing valuable insights into the underlying mechanisms of fish sex determination. [ABSTRACT FROM AUTHOR]

Background: 46,XX testicular disorder/difference of sex development (46,XX DSD) is a rare congenital condition, characterized by a combination of the typical female sex chromosome constitution, 46,XX, and a variable male phenotype. In the majority of individuals with 46,XX DSD, a Y chromosome segment containing the sex-determining region gene (SRY) has been translocated to the paternal X chromosome. However, the precise genomic content of the translocated segment and the genome-wide effects remain elusive. Methods: We performed long-read DNA sequencing, RNA sequencing and DNA methylation analyses on blood samples from 46,XX DSD (n = 11), male controls (46,XY; variable cohort sizes) and female controls (46,XX; variable cohort sizes), in addition to RNA sequencing and DNA methylation analysis on blood samples from males with Klinefelter syndrome (47,XXY, n = 22). We also performed clinical measurements on all 46,XX DSD and a subset of 46,XY (n = 10). Results: We identified variation in the translocated Y chromosome segments, enabling subcategorization into 46,XX DSD (1) lacking Y chromosome material (n = 1), (2) with short Yp arms (breakpoint at 2.7–2.8 Mb, n = 2), (3) with medium Yp arms (breakpoint at 7.3 Mb, n = 1), and (4) with long Yp arms (n = 7), including deletions of AMELY, TBLY1 and in some cases PRKY. We also identified variable expression of the X-Y homologues PRKY and PRKX. The Y-chromosomal transcriptome and methylome reflected the Y chromosome segment lengths, while changes to autosomal and X-chromosomal regions indicated global effects. Furthermore, transcriptional changes tentatively correlated with phenotypic traits of 46,XX DSD, including reduced height, lean mass and testicular size. Conclusion: This study refines our understanding of the genetic composition in 46,XX DSD, describing the translocated Y chromosome segment in more detail than previously and linking variability herein to genome-wide changes in the transcriptome and methylome. Plain English summary: Our sex chromosome constitution determines our sex, with the presence of a Y chromosome causing male sex determination (typically 46,XY) and the lack hereof resulting in female sex development (typically 46,XX). However, individuals can become male despite of them presenting with the classical female chromosome constitution. We term this "46,XX testicular disorder/difference of sex development" or "46,XX DSD" for short. Individuals with this condition are affected by a number of traits, such as infertility, short stature and altered hormone levels. We know that most cases of 46,XX DSD are caused by the sex-determining region of the Y chromosome being moved to one of the X chromosomes. However, we do not know the more precise size of the Y-chromosomal section or its effects on the genome. In this study we investigated 11 individuals with 46,XX DSD using novel and precise techniques than previously applied. Analyzing DNA, we found that their Y-chromosomal sections varied. This was reflected in multiple types of additional genetic analyses, investigating modifications to DNA and expression of genes. Our findings are the most accurate description of the Y-chromosomal section in 46,XX DSD to date, and indicate that the genomes of individuals with 46,XX DSD differ, with many potential mechanisms of action. Highlights: • From a cohort of 11 individuals with 46,XX testicular DSD, the profile of Y chromosome segments was described in more detail than previously and used to sub-categorize subjects into four groups; SRY-negative, short Yp (2.7–2.8 Mb), medium Yp (7.3 Mb) and long Yp. • In individuals with long Yp segments, a characteristic loss of AMELY, TBL1Y and in some cases PRKY was observed. • Variable expression of the X-Y homologous gene pair PRKX and PRKY was observed, suggesting a compensatory mechanism. • The lengths of Y chromosome segments were reflected in the transcriptome and methylome. • Differential expression and methylation of autosomes suggested genome-wide effects. [ABSTRACT FROM AUTHOR]

Aim: The objective of the study is to fill the gaps in knowledge about the third trochanter (TT) by quantifying these anatomical measurements and examining the morphological characteristics associated with its presence. Materials and Methods: The length, diameter, types, location, and distances to the greater and lesser trochanters of the third trochanter were determined. Measurements of the greater trochanter, lesser trochanter, and gluteal tubercle lengths and diameters of 144 femurs available in the Medical Faculty laboratory were taken using a digital caliper to calculate their relationships with the third trochanter (TT). Results: In our study of 144 dry femurs, we identified the presence of TTs in 25.35% of cases, which equates to 36 femurs. Notably, we observed significant gender differences in the prevalence of TTs, with 27 males having TTs compared to 9 females, indicating a higher occurrence of TTs in males (p= 0.027). Average femur length and width were 41.23 mm and 27.05 mm, Greater trochanter had dimensions of 45.27 mm by 38.66 mm, and lesser trochanter measured 24.89 mm by 17.78 mm. In TT-identified femurs, the TT had an average length and diameter of 39.46 mm and 26.01 mm, respectively. The study also provided measurements for gluteal tuberosity and trochanter distances, helping in orthopedic and anatomical research. Conclusion: In our study conducted on 144 dry femurs with sex determination using morphometric methods, it was found that the third trochanter (TT) was detected in 25.35% of the cases, showing significant sexual dimorphism in favor of males. These femurs exhibited specific morphological characteristics, including an increased superior sagittal diameter, elevated diaphysis platymetry index, and an enlarged greater trochanter. Additionally, the presence of the third trochanter may reflect adaptations to mechanical forces and evolutionary changes, making it a valuable trait for anatomical and genomic studies, as well as surgical procedures that require access to the femoral medullary cavity. [ABSTRACT FROM AUTHOR]

In dioecious plants, the process of sex determination usually occurs during the reproductive stage. However, it can be challenging to determine the sex of long-lived plants with long generation times. This is true for Cycas revoluta, which produces toxic seeds in female plants, leading to a preference for male plants in public green spaces. In this study we aim to identify a morphological trait that can be used to distinguish between the sexes in C. revoluta at a very early stage of plant growth. We sampled C. revoluta seedlings/plantlets at three different early growth stages and identified the sex of individuals by PCR amplification of a male-specific molecular marker. On the same plants, we measured morphological traits, including the distance between leaflets on the leaf rachis, perimeter, area, number of indents, and leaf complexity, and evaluated their correlation with the sex of the individuals. Among all measured traits, the medium distance between leaflets on the leaf rachis was found to be a sexually dimorphic morphological trait in Cycas plantlets in all three growth stages. In particular, the distance between leaflets on the leaf rachis in the upper part of the leaf in the first stage revealed no overlap between the sexes. Whenever available, morphological traits for sex differentiation in greenhouses and plant nurseries can represent a rapid and economic tool when coupled with automatized image recognition systems. [ABSTRACT FROM AUTHOR]

The northern pike Esox lucius is a freshwater fish with low genetic diversity but ecological success throughout the Northern Hemisphere. Here, we generate an annotated chromosome-level genome assembly of 941 Mbp in length with 25 chromosome-length scaffolds. We then genotype 47 northern pike from Alaska through New Jersey at a genome-wide scale and characterize a striking decrease in genetic diversity along the sampling range. Individuals west of the North American Continental Divide have substantially higher diversity than those to the east (e.g. Interior Alaska and St. Lawrence River have on average 181 and 64K heterozygous SNPs per individual, or a heterozygous SNP every 5.2 and 14.6 kbp, respectively). Individuals clustered within each population with strong support, with numerous private alleles observed within each population. Evidence for recent population expansion was observed for a Manitoba hatchery and the St. Lawrence population (Tajima's D = −1.07 and −1.30, respectively). Several chromosomes have large regions with elevated diversity, including LG24, which holds amhby , the ancestral sex determining gene. As expected amhby was largely male-specific in Alaska and the Yukon and absent southeast to these populations, but we document some amhby (−) males in Alaska and amhby (+) males in the Columbia River, providing evidence for a patchwork of presence of this system in the western region. These results support the theory that northern pike recolonized North America from refugia in Alaska and expanded following deglaciation from west to east, with probable founder effects resulting in loss of both neutral and functional diversity (e.g. amhby). [ABSTRACT FROM AUTHOR]

The BTB gene superfamily is widely distributed among higher eukaryotes and plays a significant role in numerous biological processes. However, there is limited knowledge about the structure and function of BTB genes in the critically endangered species Alligator sinensis, which is endemic to China. A total of 170 BTB genes were identified from the A. sinensis genome, classified into 13 families, and unevenly distributed across 16 chromosomes. Analysis of gene duplication events yielded eight pairs of tandem duplication genes and six pairs of segmental duplication genes. Phylogenetics shows that the AsBTB genes are evolutionarily conserved. The cis-regulatory elements in the AsBTB family promoter region reveal their involvement in multiple biological processes. Protein interaction network analysis indicates that the protein interactions of the AsBTB genes are centered around CLU-3, mainly participating in the regulation of biological processes through the ubiquitination pathway. The expression profile and protein interaction network analysis of AsBTB genes during sex differentiation and early gonadal development indicate that AsBTB genes are widely expressed in this process and involves numerous genes and pathways for regulation. This study provides a basis for further investigation of the role of the BTB gene in sex differentiation and gonadal development in A. sinensis. [ABSTRACT FROM AUTHOR]

Dendroctonus armandi (Tsai and Li) (Coleoptera: Curculionidae: Scolytinae) is regarded as the most destructive forest pest in the Qinling and Bashan Mountains of China. The sex determination of Dendroctonus armandi plays a significant role in the reproduction of its population. In recent years, the role of the fem-1 gene in sex determination in other insects has been reported. However, the function and expression of the fem-1 gene in Dendroctonus armandi remain uncertain. In this study, three fem-1 genes were cloned and characterized. These were named Dafem-1A, Dafem-1B, and Dafem-1C, respectively. The expression levels of these three Dafem-1 genes vary at different stages of development and between the sexes. In response to different environmental treatments, including temperature, nutrients, terpenoids, and feeding duration, significant differences were observed between the three Dafem-1 genes at different developmental stages and between males and females. Furthermore, injection of double-stranded RNA (dsRNA) targeting the expressions of the Dafem-1A, Dafem-1B, and Dafem-1C genes resulted in increased mortality, deformity, and decreased emergence rates, as well as an imbalance in the sex ratio. Following the interference with Dafem-1A and Dafem-1C, no notable difference was observed in the expression of the Dafem-1B gene. Similarly, after the interference with the Dafem-1B gene, no significant difference was evident in the expression levels of the Dafem-1A and Dafem-1C genes. However, the interference of either the Dafem-1A or Dafem-1C gene results in the downregulation of the other gene. The aforementioned results demonstrate that the Dafem-1A, Dafem-1B, and Dafem-1C genes play a pivotal role in the regulation of life development and sex determination. Furthermore, it can be concluded that external factors such as temperature, nutrition, terpenoids, and feeding have a significant impact on the expression levels of the Dafem-1A, Dafem-1B, and Dafem-1C genes. This provides a crucial theoretical foundation for further elucidating the sex determination mechanism of Dendroctonus armandi. [ABSTRACT FROM AUTHOR]

The many independent transitions from hermaphroditism to separate sexes (dioecy) in flowering plants and some animal clades must often have involved the emergence of a heterogametic sex-determining locus, the basis of XY and ZW sex determination (i.e., male and female heterogamety). Current estimates indicate that XY sex determination is much more frequent than ZW, but the reasons for this asymmetry are unclear. One proposition is that separate sexes evolve through the invasion of sterility mutations at closely linked loci, in which case XY sex determination evolves if the initial male sterility mutation is fully recessive. Alternatively, dioecy may evolve via the gradual divergence of male and female phenotypes, but the genetic basis of such divergence and its connection to XY and ZW systems remain poorly understood. Using mathematical modeling, we show how dioecy with XY or ZW sex determination can emerge from the joint evolution of resource allocation to male and female function with its genetic architecture. Our model reveals that whether XY or ZW sex determination evolves depends on the trade-off between allocation to male and female function, and on the mating system of the ancestral hermaphrodites, with selection for female specialization or inbreeding avoidance both favoring XY sex determination. Together, our results cast light on an important but poorly understood path from hermaphroditism to dioecy, and provide an adaptive hypothesis for the preponderance of XY systems. Beyond sex and sex determination, our model shows how ecology can influence the way selection shapes the genetic architecture of polymorphic traits. [ABSTRACT FROM AUTHOR]

Populus tomentosa, an indigenous tree species, is widely distributed and cultivated over 1,000,000 km2 in China, contributing significantly to forest production, ecological conservation and urban–rural greening. Although a reference genome is available for P. tomentosa, the intricate interspecific hybrid origins, chromosome structural variations (SVs) and sex determination mechanisms remain confusion and unclear due to its broad and even overlapping geographical distribution, extensive morphological variations and cross infiltration among white poplar species. We conducted a haplotype‐resolved de novo assembly of P. tomentosa elite individual GM107, which comprises subgenomes a and b with a total genome size of 714.9 Mb. We then analysed the formation of hybrid species and the phylogenetic evolution and sex differentiation across the entire genus. Phylogenomic analyses suggested that GM107 likely originated from a hybridisation event between P. alba (♀) and P. davidiana (♂) which diverged at approximately 3.8 Mya. A total of 1551 chromosome SVs were identified between the two subgenomes. More noteworthily, a distinctive inversion structure spanning 2.15–2.95 Mb was unveiled among Populus, Tacamahaca, Turaga, Aigeiros poplar species and Salix, highlighting a unique evolutionary feature. Intriguingly, a novel sex genotype of the ZY type, which represents a crossover between XY and ZW systems, was identified and confirmed through both natural and artificial hybrids populations. These novel insights offer significant theoretical value for the study of the species' evolutionary origins and serve as a valuable resource for ecological genetics and forest biotechnology. [ABSTRACT FROM AUTHOR]

The Charnov‐Bull hypothesis is the leading explanation for the evolution of environmental sex determination (ESD), which includes temperature‐dependent sex determination (TSD), the most common form of ESD. Charnov‐Bull predicts a sex‐by‐incubation temperature interaction for fitness, matching offspring sex with thermal conditions that increase parental fitness. However, there is no general explanation for how the sex‐by‐temperature interaction arises. Two competing explanations for the interaction lie in the survival to maturity hypothesis (SM) and the Trivers–Willard extension (TW). Under SM, the sex that matures later is produced under optimal incubation regimes as the late‐maturing sex accrues more mortality by maturation, while TW suggests that males are always produced under optimal incubation regimes as male mating success is more sensitive to condition (general health, vigor) than female fecundity. In a system where females mature later than males, as in the painted turtle Chrysemys picta, SM and TW generate opposite predictions for the effect of incubation temperature on juvenile survival. We incubated C. picta eggs under either female‐promoting temperatures (28 ± 3 °C) or male‐promoting temperatures (25 ± 3 °C), then released the hatchlings into their natal pond. We used a Bayesian capture–mark–recapture approach to follow their survival over two growing seasons. We found a 2% depression of biweekly survival in individuals incubated under the cooler temperature, providing subtle support for SM. Incubation treatments did not influence growth. Large‐scale field experiments such as this one will be necessary for understanding TSD evolution, and we underline general principles to execute such experiments successfully. [ABSTRACT FROM AUTHOR]

ABSTRACT In maize, sex is determined by the formation of staminate and pistillate florets from an initially bisexual floral meristem through action of Silkless1 (Sk1), Tasselseed1 (Ts1) and Tasselseed2 (Ts2) genes. In this study, separate temperate donors having mutant sk1 (EC904829 and EC904831), ts1 (EC904827) and ts2 (EC904824) genes were crossed with sub‐tropical inbreds (HKI323 and HKI1105) to investigate the genetics and interaction of silkless and tasselseed traits. The monogenic and nuclear inheritance of sk1, ts1 and ts2 genes was established in a standard Mendelian principles in both monohybrid and dihybrid crosses irrespective of genetic background. About 444 F2 progenies across digenic population ‐A, ‐B and ‐C segregated as 239 normal: 109 silkless: 96 tasselseed, and 377 progenies of digenic populations ‐D, ‐E and ‐F segregated with 214 normal: 79 silkless: 84 tasselseed plants revealing recessive epistatic interaction (9:3:4) of sk1 with two ts mutations (ts1 and ts2). No progeny with both silkless and tasselseed phenotype was observed. The double mutants (sk1sk1/ts1ts1 and sk1sk1/ts2ts2) were identified through progeny testing. Our study emphasize the untapped potential of these mutants, providing a renewed focus for maize breeders worldwide. [ABSTRACT FROM AUTHOR]

The past two decades have witnessed a rapid increase in the genomic sequencing of parasitoid wasps, amassing a rich dataset for detailed studies. Genome size variability in parasitoid wasps is linked to the dynamic evolution of transposable elements. Genomic studies have discovered that a number of genomic changes may be linked to key traits in parasitoid wasps, such as reduced body size, host range shift, and sex determination. The genomic data provide robust support for studying the diversity and evolution of parasitic effectors, including venoms and polydnaviruses. Deeper genomic research is poised to provide insights into the evolution of parasitoid diversity, and the genomic knowledge obtained could be used for enhancing the application of parasitoid wasps in biological control. Parasitoid wasps represent a group of parasitic insects with high species diversity that have played a pivotal role in biological control and evolutionary studies. Over the past 20 years, developments in genomics have greatly enhanced our understanding of the biology of these species. Technological leaps in sequencing have facilitated the improvement of genome quality and quantity, leading to the availability of hundreds of parasitoid wasp genomes. Here, we summarize recent progress in parasitoid wasp genomics, focusing on the evolution of genome size (GS) and the genomic basis of several key traits. We also discuss the contributions of genomics in studying venom evolution and endogenization of viruses. Finally, we advocate for increased sequencing and functional research to better understand parasitoid biology and enhance biological control. [ABSTRACT FROM AUTHOR]

Objective This proof-of-concept study assessed how confidently an artificial intelligence (AI) model can determine the sex of a fetus from an ultrasound image. Study Design Analysis was performed using 19,212 ultrasound image slices from a high-volume fetal sex determination practice. This dataset was split into a training set (11,769) and test set (7,443). A computer vision model was trained using a transfer learning approach with EfficientNetB4 architecture as base. The performance of the computer vision model was evaluated on the hold out test set. Accuracy, Cohen's Kappa and Multiclass Receiver Operating Characteristic area under the curve (AUC) were used to evaluate the performance of the model. Results The AI model achieved an Accuracy of 88.27% on the holdout test set and a Cohen's Kappa score 0.843. The ROC AUC score for Male was calculated to be 0.896, for Female a score of 0.897, for Unable to Assess a score of 0.916, and for Text Added a score of 0.981 was achieved. Conclusion This novel AI model proved to have a high rate of fetal sex capture that could be of significant use in areas where ultrasound expertise is not readily available. Key Points This is the first proof-of-concept AI model to determine fetal sex. This study adds to the growing research in ultrasound AI. Our findings demonstrate AI integration into obstetric care. [ABSTRACT FROM AUTHOR]

Two methods for preimplantation genetic testing (PGT) have been described for equine embryos: trophoblast cell biopsy (TCB) or blastocoele fluid aspiration (BFA). While TCB is widely applied for both in vivo - and in vitro -produced embryos, BFA has been mostly utilized for in vivo -produced embryos. Alternative methods for PGT, including analysis of cell-free DNA (CFD) in the medium where in vitro -produced embryos are cultured, have been reported in humans but not for equine embryos. In Experiment 1, in vivo - (n = 10) and in vitro -produced (n = 13) equine embryos were subjected to BFA, cultured for 24 h, then subjected to TCB, and cultured for additional 24 h. No detrimental effect on embryonic diameter or re-expansion rates was observed for either embryo group (P > 0.05). In Experiment 2, the concordance (i.e., agreement on detecting the same embryonic sex using two techniques) among BFA, TCB, and the whole embryo (Whole) was studied by detecting the sex-determining region Y (SRY) or testis-specific y-encoded protein 1 (TSPY) (Y-chromosome), and androgen receptor (AR ; X-chromosome) genes using PCR. Overall, a higher concordance for detecting embryonic sex was observed among techniques for in vivo -produced embryos (67–100 %; n = 14 embryos) than for in vitro -produced embryos (31–92 %; n = 13 embryos). The concordance between sample types increased when utilizing TSPY (77–100 %) instead of SRY (31–100 %) as target gene. In Experiment 3, CFD analysis was performed on in vitro-produced embryos to determine embryonic sex via PCR (SRY [Y-chromosome] and amelogenin – AMEL [X- and Y-chromosomes]). Overall, CFD was detected in all medium samples, and the concordance between CFD sample and the whole embryo was 60 % when utilizing SRY and AMEL genes. In conclusion, equine embryos can be subjected to two biopsy procedures (24 h apart) without apparent detrimental effects on embryonic size. For in vivo -, but not for in vitro -produced equine embryos, BFA can be considered a potential alternative to TCB for PGT. Finally, CFD can be further explored as a non-invasive method for PGT in in vitro produced equine embryos. • Equine in vivo- and in vitro -produced embryos were subjected to two biopsies. • An apparent negative effect on embryonic diameter was not observed. • TSPY was more efficient than SRY as a target gene for sex determination of equine embryos. • Blastocele fluid aspiration yielded similar results to trophoblast cells for in vivo embryos. • Cell-free DNA can be isolated from spent medium where in vitro embryos are cultured. [ABSTRACT FROM AUTHOR]

Fifty years ago, researchers discovered a link between ambient temperature and the sex of turtle embryos. More recently, significant progress has been made in understanding the influence of temperature on freshwater turtles. However, our understanding of the key genetic factors in other turtle groups, such as sea turtles, remains limited. To address this gap, we conducted RNA-seq analyses on embryonic tissues from the sea olive ridley turtle during the thermosensitive period (stages 21–26) at temperatures known to produce males (26 °C) and females (33 °C). Our findings revealed that incubation temperatures primarily influence genes with broad expression across tissues due to differential cell division rates and later have an effect regulating gonad-specific transcripts. This effect is mostly related to gene activation rather than transcription repression. We performed transcriptome analyses following shifts in incubation temperatures of bi-potential gonads. This approach allowed us to identify genes that respond rapidly and may be closer to the beginning of the temperature-sensing pathway. Notably, we observed swift adaptations in the expression levels of chromatin modifiers JARID2 and KDM6B , as well as the splicing factor SRSF5 , and transcription regulators THOC2 , DDX3X and CBX3 , but little impact in the overall gonad-specific pathways, indicating that temperature-sensing genes may change rapidly but the rewiring of the gonad's developmental fate is complex and resilient. Sea turtles, one of the most iconic creatures of our oceans, confront a troubling reality of endangerment, a peril magnified by the looming specter of climate change. This climatic shift is gradually increasing the temperature of the nesting beaches thus causing dramatic male/female population biases. Conservation efforts will need genetic and molecular information to reverse the negative effects of climate change on the populations. In this study, we conducted the first transcriptomic analysis of embryonic tissues, including gonads, brain, liver, and mesonephros, in the olive ridley sea turtle during the critical thermosensitive period spanning stages 21–26. We examined both male-producing (26 °C) and female-producing (33 °C) temperatures and found that incubation temperatures influence temperature-sensitive genes that are either expressed globally or specifically associated with the gonads. These findings indicate that incubation temperatures predominantly sway genes with broad expression patterns due to differential cell division rates. This natural process was opted in the gonads to drive sex determination. We also identified genes that are rapidly capable of sensing temperature changes and that could play a role in the activation of the sex determination pathway. Overall, our study sheds light on the intricate interplay between temperature and gene expression during sea turtle development, revealing dynamic changes in the transcriptome and highlighting the involvement of key genetic players in sex determination. [Display omitted] • Incubation temperatures primarily influence genes with broad expression. • Temperature-sensitive genes are related to cell division rates. • Recruitment of temperature-sensitive genes in the gonad drive sex determination. • Temperature shifts during TSD distinguish between slow and rapid responding genes. • Temperature-sensing genes adapt rapidly but rewiring of the gonad's fate is resilient. [ABSTRACT FROM AUTHOR]

Objectives An important aspect of forensic investigation is determining the sex of an unidentified person. The frontal sinus is unique and remains intact, thus making it suitable for forensic analysis. The main objective of this study is to determine the sex of an individual by frontal sinus using a multidetector computed tomography scan. Materials and Methods A total of 100 patients (50 males and 50 females) were included in the study, and different parameters of the frontal sinus for both sides were analyzed, that is height, width, depth, and total length. Statistical Analysis Descriptive statistics of all the variables were computed and compared. SPSS version 16 was used to perform the Mann–Whitney U test, binary logistic regression, and receiver operating characteristic (ROC) curve analysis on the acquired data. Results The result suggested that males have higher mean values than females, with the left frontal sinus height being the only variable to be statistically significant (p < 0.05). Based on the ROC curve analysis, the optimum cutoff value was 0.489, which means if the predicted probability value was less than 0.489, the individual was considered a male; and if the predicted probability value was ≥0.489, the individual was considered a female. The accuracy of the mathematical model based on binary logistic regression analysis for determining sex was 70% for females and 66% for males. Conclusion The present study plays a significant role in determining sex in the Indian population by using left frontal sinus height measurement through a multidetector computed tomography scan. [ABSTRACT FROM AUTHOR]

The date palm (Phoenix dactylifera L.) is a dioecious plant, and its sexual characteristics remain indiscernible until it reaches the reproductive stage, typically between 4 and 5 years of age. The Medjool variety is widely grown in Palestine and the neighboring regions. Early identification of male and female seedlings could significantly benefit date palm cultivation and breeding efforts. This study aimed to confirm the effectiveness of microsatellite markers in distinguishing between male and female date palms within the cv. Medjool variety. Out of eight microsatellite or simple sequence repeat (SSR) primers used, four markers (mPdCIR015, mPdCIR035, mPdCIR078 and mPdCIR093) were able to determine the sex of the date palm tree (cv. Medjool) at an early stage. Practically, a combination of any of these two SSR markers could be used to determine the sex of date palm at seedling stage cv. Medjool. mPdCIR010 and mPdCIR093 produced male specific bands (325 bp) and (156 bp) respectively. On the other side, mPdCIR015 and mPdCIR078 produced unique female bands (160 and 128 bp), respectively. 15 loci were identified, averaging 2.1 loci per primer. SSR markers were able to provide a reliable technique for sex determination in date palm (cv. Medjool) at an early stage. The utilization of SSR markers will not only advance but also facilitate the establishment of a commercial date palm cultivation through the breeding program in Palestine and the surrounding region. Primer mPdCIR035 (325 bp) and mPdCIR093 (156 bp) occurred in all date palm male samples and absent in all female samples indicates a promising candidate markers to detect the sex in date palm seedlings at early stage. [ABSTRACT FROM AUTHOR]

Simple Summary: Artificial sex hormones such as 17α-methyltestosterone (MT) are used as useful tools for sex determination of major cultured fish species. However, the metamorphosis and embryology by MT treatment in Japanese eel Anguilla japonica remain largely unknown. In this study, MT induced male characteristics and morphological changes in juvenile eels, particularly a shortened snout length and pigmentation of the fin. Additionally, we successfully identified and demonstrated the involvement of specific genes associated with the determination of pigmentation, such as melanocortin 1 receptor (MC1R), tyrosinase (Tyr), and dopachrome tautomerase (DCT), following MT treatment. Our study presents the sex differentiation, deformities, and pigmentation development in the juvenile eels caused by MT treatment, providing basic knowledge for both growth and development studies analyzing sex steroids. 17α-methyltestosterone (MT) is a synthetic steroid used to induce masculinization when administered during the larval stage of fish. However, the side effects of MT on eel are still poorly understood and, in this study, we examined the various effects of MT on juvenile eel A. japonica (100.63 ± 8.56 mm total length (TL)). To further investigate growth and sex differentiation, juvenile eels (n = 1000) were exposed to 25 µg/g MT for 6 months. We analyzed growth-related factors, sex steroid hormones, skin pigmentation, and color-related gene expression. Through this study, we found a 90% sex conversion of juvenile eels to males using MT treatment. In the MT-treated eel group (285.97 ± 26.21 mm TL) where sexual maturity was induced, spermatogonia stages were observed in the gonads. In contrast, the control group (395.97 ± 27.72 mm TL) exhibited an 80% immaturity rate, with only 20% of the subjects that were rapidly developing displaying early oogonia. ELISA analysis results showed that the level of growth hormone, which is known to be secreted from spermatogonia, did not change as a result of MT treatment. We confirmed that MT delayed growth and caused morphological changes, particularly a shortened snout length and pigmentation of the fin. The total length, body weight, and snout length were considerably lower in the experimental group than in the control group. In addition, in histological analysis we also observed that some of the MT-treated group (5 out of 10 fish) showed liver atrophy and inflammation, and physiological analysis showed that the cortisol concentration increased in the MT-treated eels. Interestingly, we found that some pigment color-related genes, such as melanocortin 1 receptor (MC1R), tyrosinase (Tyr), and dopachrome tautomerase (DCT), were significantly overexpressed in the fins of MT-treated eels. These results suggest that the treatment of A. japonica larvae with MT induced masculinization but also causes growth side effects from the use of synthetic hormones. [ABSTRACT FROM AUTHOR]

Sex determination in animals is not only determined by karyotype but can also be modulated by environmental cues like temperature via unclear transduction mechanisms. Moreover, in contrast to earlier views that sex may exclusively be determined by either karyotype or temperature, recent observations suggest that these factors rather co-regulate sex, posing another mechanistic mystery. Here, we discovered that certain wild-isolated and mutant C. elegans strains displayed genotypic germline sex determination (GGSD), but with a temperature-override mechanism. Further, we found that BiP, an ER chaperone, transduces temperature information into a germline sex-governing signal, thereby enabling the coexistence of GGSD and temperature-dependent germline sex determination (TGSD). At the molecular level, increased ER protein-folding requirements upon increased temperatures lead to BiP sequestration, resulting in ERAD-dependent degradation of the oocyte fate-driving factor, TRA-2, thus promoting male germline fate. Remarkably, experimentally manipulating BiP or TRA-2 expression allows to switch between GGSD and TGSD. Physiologically, TGSD allows C. elegans hermaphrodites to maintain brood size at warmer temperatures. Moreover, BiP can also influence germline sex determination in a different, non-hermaphroditic nematode species. Collectively, our findings identify thermosensitive BiP as a conserved temperature sensor in TGSD, and provide mechanistic insights into the transition between GGSD and TGSD. Synopsis: Temperature has long been known to modulate sex in various animals, but the mechanism for transducing temperature into a sex reversal signal is still a mystery. This work identifies BiP as a sensor that translates ambient temperature cues into the germline sex determination signal in C. elegans. Genotypic germline sex determination (GGSD) in wild-isolated and mutant C. elegans strains can be overridden by temperature changes. BiP sequestration for increased ER protein folding burden upon temperature elevation causes ERAD-mediated downregulation of the oocyte fate-driving factor, TRA-2. BiP's role in germline sex determination is conserved in a dioecious nematode species. Manipulation of BiP-dependent transduction allows switching between GGSD and temperature-dependent germline sex determination (TGSD). TGSD facilitates brood size maintenance in C. elegans hermaphrodites at elevated temperatures. Masculinization of the C. elegans germline in response to temperature elevation is mediated by BiP, which can override genotypic sex determination. [ABSTRACT FROM AUTHOR]

Litchi exhibits a large number of flowers, many flowering batches, and an inconsistent ratio of male and female flowers, frequently leading to a low fruit-setting rate. Floral sexual differentiation is a crucial phase in perennial trees to ensure optimal fruit production. However, the mechanism behind floral differentiation remains unclear. The objective of the study was to identify the role of auxin in floral differentiation at the transcriptional level. The results showed that the ratio of female flowers treated with naphthalene acetic acid (NAA) was significantly lower than that of the control stage (M0/F0). The levels of endogenous auxin and auxin metabolites were measured in male and female flowers at different stages of development. It was found that the levels of IAA, IAA-Glu, IAA-Asp, and IAA-Ala were significantly higher in male flowers compared to female flowers. Next-generation sequencing and modeling were employed to perform an in-depth transcriptome analysis on all flower buds in litchi 'Feizixiao' cultivars (Litchi chinensis Sonn.). Plant hormones were found to exert a significant impact on the litchi flowering process and flower proliferation. Specifically, a majority of differentially expressed genes (DEGs) related to the auxin pathway were noticeably increased during male flower bud differentiation. The current findings will enhance our comprehension of the process and control mechanism of litchi floral sexual differentiation. It also offers a theoretical foundation for implementing strategies to regulate flowering and enhance fruit production in litchi cultivation. [ABSTRACT FROM AUTHOR]

Background: Blotched snakehead (Channa maculata) displays significant sexual dimorphism, with males exhibiting faster growth rates and larger body sizes compared to females. The cultivation of the all-male population of snakeheads holds substantial economic and ecological value. Nonetheless, the intricate processes governing the development of bipotential gonads into either testis or ovary in C. maculata remain inadequately elucidated. Therefore, it is necessary to determine the critical time window of sex differentiation in C. maculata, providing a theoretical basis for sex control in production practices. Methods: The body length and weight of male and female C. maculata were measured at different developmental stages to reveal when sexual dimorphism in growth initially appears. Histological observations and spatiotemporal comparative transcriptome analyses were performed on ovaries and testes across various developmental stages to determine the crucial time windows for sex differentiation in each sex and the sex-related genes. Additionally, qPCR and MG2C were utilized to validate and locate sex-related genes, and levels of E2 and T were quantified to understand sex steroid synthesis. Results: Sexual dimorphism in growth became evident starting from 90 dpf. Histological observations revealed that morphological sex differentiation in females and males occurred between 20 and 25 dpf or earlier and 30–35 dpf or earlier, respectively, corresponding to the appearance of the ovarian cavity or efferent duct anlage. Transcriptome analyses revealed divergent gene expression patterns in testes and ovaries after 30 dpf. The periods of 40–60 dpf and 60–90 dpf marked the initiation of molecular sex differentiation in females and males, respectively. Male-biased genes (Sox11a, Dmrt1, Amh, Amhr2, Gsdf, Ar, Cyp17a2) likely play crucial roles in male sex differentiation and spermatogenesis, while female-biased genes (Foxl2, Cyp19a1a, Bmp15, Figla, Er) could be pivotal in ovarian differentiation and development. Numerous biological pathways linked to sex differentiation and gametogenesis were also identified. Additionally, E2 and T exhibited sexual dimorphism during sex differentiation and gonadal development. Based on these results, it is hypothesized that in C. maculata, the potential male sex differentiation pathway, Sox11a–Dmrt1–Sox9b, activates downstream sex-related genes (Amh, Amhr2, Gsdf, Ar, Cyp17a2) for testicular development, while the antagonistic pathway, Foxl2/Cyp19a1a, activates downstream sex-related genes (Bmp15, Figla, Er) for ovarian development. Conclusions: This study provides a comprehensive overview of gonadal dynamic changes during sex differentiation and gametogenesis in C. maculata, establishing a scientific foundation for sex control in this species. Plain language summary: Blotched snakehead (Channa maculata) exhibits significant sexual dimorphism, as males display faster growth rates and larger body sizes compared to females. The cultivation of the all-male population of snakeheads holds substantial economic and ecological value. However, the mechanisms underlying sex determination and differentiation in C. maculata remain insufficiently elucidated. In this study, sexual dimorphism in growth became evident starting from 90 dpf through the measurement of body length and weight of male and female C. maculata at different developmental stages. Histological observations indicated that morphological sex differentiation in females and males occurred at 20–25 dpf or earlier and 30–35 dpf or earlier, respectively, corresponding to the appearance of the ovarian cavity or efferent duct anlage. Transcriptome analyses revealed divergent gene expression patterns in male and female gonads after 30 dpf, suggesting that the period preceding 30 dpf might be the critical time window for sex control in C. maculata. The periods of 40–60 dpf and 60–90 dpf marked the initiation of molecular sex differentiation in females and males, respectively. Male-biased genes (Sox11a, Dmrt1, Amh, Amhr2, Gsdf, Ar, Cyp17a2) likely play crucial roles in testicular differentiation and spermatogenesis, while female-biased genes (Foxl2, Cyp19a1a, Bmp15, Figla, Er) could be pivotal in ovarian differentiation and oogenesis. Additionally, numerous biological pathways linked to sex differentiation and gametogenesis were identified. Moreover, sexual dimorphism was observed in the levels of E2 and T during gonadal differentiation and development. Based on these findings, it is hypothesized that in C. maculata, the potential male sex differentiation pathway, Sox11a–Dmrt1–Sox9b, activates downstream sex-related genes (Amh, Amhr2, Gsdf, Ar, Cyp17a2) for testicular development, while the antagonistic pathway, Foxl2/Cyp19a1a, activates downstream sex-related genes (Bmp15, Figla, Er) for ovarian development. This study provides a comprehensive overview of gonadal dynamic changes during sex differentiation and gametogenesis in C. maculata, thereby establishing a scientific foundation for sex control in this species. Highlights: Sexual dimorphism in growth became apparent starting from 90 dpf. The morphological differentiation of ovary and testis occurred at 20–25 dpf or earlier and 30–35 dpf or earlier, respectively, and the period preceding 30 dpf may be the critical time for sex control in C. maculata. Male-biased genes (Sox11a, Dmrt1, Amh, Amhr2, Gsdf, Ar, Cyp17a2) likely play crucial roles in testicular differentiation and spermatogenesis, whereas female-biased genes (Foxl2, Cyp19a1a, Bmp15, Figla, Er) could be pivotal in ovarian differentiation and oogenesis. The fate of undifferentiated primordial gonads in C. maculata may be determined by the antagonistic action of the Sox11a–Dmrt1–Sox9b and Foxl2/Cyp19a1a pathways. [ABSTRACT FROM AUTHOR]

The sex determination system of largemouth bass (Micropterus salmoides, LMB) is XX/XY; however, the underlying molecular mechanisms involved in early sex differentiation, gonadal development, and exogenous hormone-induced sex reversal remain unknown. In this study, LMB at 15 days post-hatching (dph) were fed diets containing 20 mg/kg of 17a-methyltestosterone (17a-MT) or 30 mg/kg of 17ß-estradiol (17ß-E2) for 60 days, respectively. Serum steroid levels, histological observations of the gonads, and identification of sex-specific markers were employed to screen the gonads of 60-day-old normal female fish (XX-F), normal male fish (XY-M), 17ß-E2 induced pseudo-female fish (XY-F), and 17a-MT-induced pseudo-male fish (XX-M) for transcriptome sequencing in order to uncover genes and pathway involved in the process of sexual reversal. The results from histology and serum sex steroid hormone analysis showed that both 17a-MT and 17ß-E2 were capable of inducing sex reversal of LMB at 15 dph. Transcriptome results revealed a total of 2,753 genes exhibiting differential expression, and the expression pattern of these genes in the gonads of XX-M or XY-F resembled that of normal females or males. The male sex-biased genes that are upregulated in XX-M and downregulated in XY-F are referred to as key genes for male reversal, while the female sex-biased genes that are upregulated in XY-F and downregulated in XX-M are referred to as key genes for female reversal. Finally, 12 differentially expressed genes (DEGs) related to male sex reversal were screened, including star2, cyp17a, cyp11b1, dmrt1, amh, sox9a, katnal1, spata4, spata6l, spata7, spata18 and foxl3. 2DEGs (foxl2a and cyp19a1b) were found to be associated with female sex reversal. The changes in these genes collectively influence the direction of sex differentiation of LMB. Among them, star2, dmrt1 and cyp19a1b with significantly altered expression levels may play potentially crucial role in the process of gender reversal. The expression patterns of 21 randomly selected genes were verified using qRT-PCR which confirmed the reliability and accuracy of the RNA-seq results. These findings not only enhance our understanding of the molecular basis underlying sex reversal but also provide crucial data support for future breeding research on unisexual LMB. [ABSTRACT FROM AUTHOR]

Introduction: Endosymbiotic bacteria in the genus Wolbachia have evolved numerous strategies for manipulating host reproduction in order to promote their own transmission. This includes the feminization of males into functional females, a well-studied phenotype in the isopod Armadillidium vulgare. Despite an early description of this phenotype in isopods and the development of an evolutionary model of host sex determination in the presence of Wolbachia, the underlying genetic mechanisms remain elusive. Methods: Here we present the first complete genomes of the three feminizing Wolbachia (wVulC, wVulP, and wVulM) known to date in A. vulgare. These genomes, belonging to Wolbachia B supergroup, contain a large number of mobile elements such as WO prophages with eukaryotic association modules. Taking advantage of these data and those of another Wolbachia-derived feminizing factor integrated into the host genome (f element), we used a comparative genomics approach to identify putative feminizing factors. Results: This strategy has enabled us to identify three prophage-associated genes secreted by the Type IV Secretion System: one ankyrin repeat domaincontaining protein, one helix-turn-helix transcriptional regulator and one hypothetical protein. In addition, a latrotoxin-related protein, associated with phage relic genes, was shared by all three genomes and the f element. Conclusion: These putative feminization-inducing proteins shared canonical interaction features with eukaryotic proteins. These results pave the way for further research into the underlying functional interactions. [ABSTRACT FROM AUTHOR]

One of the crucial steps in the process of identification of human remains is sex determination of an unknown individual. Sex can be determined using the human skeleton, especially by examining the pelvis and skull. Odontometric analysis and assessment of sexual dimorphism of the human dentition has been less investigated, especially in primary dentition. Hence, this research was designed to verify the presence of sexual dimorphism through odontometric approach in paediatric population of Tamil Nadu, India. The present study was performed on 229 females and 244 males between 3 and 6 years of age. Linear measurements such as maximum mesio distal width, maximum bucco lingual width and clinical crown length were measured in all the primary teeth. Statistical analysis was performed using the Statistical Package for Social Science version 20.0 software (SPSS Inc., Chicago, IL, USA). Mann–Whitney-U test was used to check the statistical significance of the differences observed between males and females. Six equations were derived by discriminant function analysis for practical use. Sexual dimorphism existed in odontometric parameters of primary dentition. The maximum sexual dimorphism was observed in maximum bucco lingual width of 51 and maximum bucco lingual width of 75. The equations derived using discriminant function analysis yielded a jackknife accuracy ranging between 87.5% and 99.8%. These equations may be used to assess the sex from the children of Tamil Nadu, India. [ABSTRACT FROM AUTHOR]

Sex assessment is one of the first steps of routine forensic anthropological examinations and it provides a crucial element to identify a set of human skeletal remains. In bioarchaeological contexts, this assessment is also important, as it helps in the reconstruction of past societies. Sex determination can be achieved by using several morphological or metric traits of the skull and postcranial skeleton, which have been found to have varying degrees of accuracy. In 1969 Phenice proposed a methodology focusing on three traits located on the pubis. These traits were described as either having a female or male morphology with ambiguity being rare. Phenice's method became regularly utilized as it was considered to be reliable. In 2012, Klales and colleagues published a revision of Phenice's method, as they found that it did not capture the variation in the expression of the three traits. Klales and co-authors created a visual ordinal scale of 1–5 for each of the three traits Phenice originally identified, thus adding three extra possible forms of expression. The purpose of the present research was to test both the original and revised methodologies on the same skeletal population in order to evaluate their suitability for the assessment of sex. The Luís Lopes Anthropological collection in Lisbon was used; 117 males and 117 females were scored using both methodologies. The results showed that the original method performed better (96.5% accuracy) than the revised method (92.7%). [ABSTRACT FROM AUTHOR]

In the present study, it is aimed to reveal the performances of different classification algorithms in sex determination from first cervical vertebra, that is, atlas measurements. The classification success of 4 different machine learning algorithms was comparatively examined for the purpose of sex determination by evaluating 22 atlas measurements on cone beam computed tomography (CBCT) images of 145 female and 145 male adults. Logistic regression (LR), classification and regression tree (CART), support vector machine (SVM) and neural network (NN) algorithms were used for sex diagnosis. Area under the ROC curve (AUC), classification accuracy (CA), Fl-ratio, Precision and Recall indexes were used for model performances. Except for 2 measurements, there was a significant difference between men and women in terms of 20 other parameters (p<0.05). The adjusted effects of these parameters on sex determination were examined with multivariate models and algorithms, and the success of all 4 algorithms was quite good. The success of the NN algorithm (Accuracy 91.3 %; 0.87 Specificity, 0.85 Sensitivity) in correctly classifying male and female was the highest, followed by the LR algorithm (Accuracy 90.9 %; 0.86 Specificity, 0.83 Sensitivity). It was found that the machine learning algorithm applied to the variables of the atlas gave high accuracy regarding sex and the NN model was highly effective in sex determination. In addition, a large morphometric database of atlas was presented in our results. [ABSTRACT FROM AUTHOR]

Since the facial bone remains are mostly damaged or fractured in the crime scenes, the occipital bone (OB) is a possible skull bone to be used for sex determination in forensic sciences. The high accuracy of the use of the OB for sex estimation has been reported in many populations. This recent study attempted to modify and apply the 12 parameters on OB for such determination in the Northeastern Thai skulls. Discriminant function analyses and descriptive statistics were performed. The results showed that all parameters including the hormion-basion length, bi-lower part of temporo-occipital suture breadth, bi-asterios breadth, opisthion-lambda length, foramen magnum breadth, foramen magnum length, right-lower part of temporo-occipital suture to opisthion length, left-lower part of temporo-occipital suture to opisthion length, right-asterion to basion length, left-asterion to basion length, right-asterion to lambda length, and left-asterion to lambda length of males were significantly higher than those of females (P<0.01). Interestingly the discriminant equation analyzed from univariable showed that the temporo-occipital suture breadth (TOB) has the highest accuracy rate (75.4 %) among 12 parameters. For multivariable analysis via stepwise method, the hormion-basion length (HBL), temporo-occipital suture breadth (TOB), and left asterion to basion length (Lt. ABL) provided the highest rate of accuracy (78.8 %). In conclusion, this study suggested that TOB, HBL, and Lt. ABL are potential parameters to be used for sex determination on dry occipital bone remains of the Northeastern Thai population. [ABSTRACT FROM AUTHOR]

Y-chromosome–encoded master transcription factor SRY functions in the embryogenesis of therian mammals to initiate male development. Through interactions of its conserved highmobility group box within a widened DNA minor groove, SRY and related Sox factors induce sharp bends at specific DNA target sites. Here, we present the crystal structure of the SRY high-mobility group domain bound to a DNA site containing consensus element 50 -ATTGTT. The structure contains three complexes in the asymmetric unit; in each complex, SRY forms 10 hydrogen bonds with minor-groove base atoms in 50 - CATTGT/ACAATG-30, shifting the recognition sequence by one base pair (italics). These nucleobase interactions involve conserved residues Arg7, Asn10, and Tyr74 on one side of intercalated Ile13 (the cantilever) and Arg20, Asn32, and Ser36 on the other. Unlike the less-bent NMR structure, DNA bend angles (69–84) of the distinct box–DNA complexes are similar to those observed in homologous Sox domain-DNA structures. Electrophoretic studies indicate that respective substitutions of Asn32, Ser36, or Tyr74 by Ala exhibit slightly attenuated specific DNA-binding affinity and bend angles (70– 73) relative to WT (79). By contrast, respective substitutions of Arg7, Asn10, or Arg20 by Ala markedly impaired DNAbinding affinity in association with much smaller DNA bend angles (53–65). In a rodent cell-based model of the embryonic gonadal ridge, full-length SRY variants bearing these respective Ala substitutions exhibited significantly decreased transcriptional activation of SRY’s principal target gene (Sox9). Together, our findings suggest that nucleobase-specific hydrogen bonds by SRY are critical for specific DNA binding, bending, and transcriptional activation. [ABSTRACT FROM AUTHOR]

The fall armyworm (Spodoptera frugiperda) poses a substantial threat to many important crops worldwide, emphasizing the need to develop and implement advanced technologies for effective pest control. CRISPR/Cas9, derived from the bacterial adaptive immune system, is a prominent tool used for genome editing in living organisms. Due to its high specificity and adaptability, the CRISPR/Cas9 system has been used in various functional gene studies through gene knockout and applied in research to engineer phenotypes that may cause economical losses. The practical application of CRISPR/Cas9 in diverse insect orders has also provided opportunities for developing strategies for genetic pest control, such as gene drive and the precision-guided sterile insect technique (pgSIT). In this review, a comprehensive overview of the recent progress in the application of the CRISPR/Cas9 system for functional gene studies in S. frugiperda is presented. We outline the fundamental principles of applying CRISPR/Cas9 in S. frugiperda through embryonic microinjection and highlight the application of CRISPR/Cas9 in the study of genes associated with diverse biological aspects, including body color, insecticide resistance, olfactory behavior, sex determination, development, and RNAi. The ability of CRISPR/Cas9 technology to induce sterility, disrupt developmental stages, and influence mating behaviors illustrates its comprehensive roles in pest management strategies. Furthermore, this review addresses the limitations of the CRISPR/Cas9 system in studying gene function in S. frugiperda and explores its future potential as a promising tool for controlling this insect pest. [ABSTRACT FROM AUTHOR]