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Sexing bird species with monomorphic plumage is generally challenging, and sexual size dimorphism (SSD) is often used to develop morphometric-based sexing tools, e.g., using discriminant functions. Within species, local selection pressures, age-related and season-related growth may, however, induce geographical and temporal variations in body size and SSD. Such variations may complicate the development of reliable morphometric-based sexing methods at a broad scale. We first investigated body size variations in a migratory shorebird species with wide breeding and wintering ranges, the Sanderling Calidris alba, within the two breeding populations (Greenland and Russia) and three staging/wintering populations (United Kingdom, Iceland and Mauritania), which belong to the same flyway. Then, for samples from each region, we tested whether site-specific (i.e., "regional") functions performed better than functions developed for birds from the other sites (i.e., "foreign" functions) or than an overall ("flyway") function that combined all sampled individuals. We found minor variations in SSD between regions, but significant differences in body size between sexes and regions. Females were larger than males and, for instance, breeders had longer wings than staging and wintering birds. Regional functions had similar sexing efficiency as any other functions applied to sample from each region, except for Western Africa where the regional function performed slightly better than some of the other functions. Furthermore, the flyway function developed after merging all subsamples had a similar efficiency than the regional functions, i.e., from 75.4% to 90% of correct sex assignment depending on the region. Given the small or lack of benefit in using regional functions, we conclude that the flyway function can be used reliably to sex Sanderlings measured at different sites, years or seasons within the East Atlantic flyway. Our results may help to develop global sexing function for other bird species. [ABSTRACT FROM AUTHOR]

Simple Summary: The process of acquiring sexed sperm involves the separation of sperm with X and Y chromosomes, allowing for the production of offspring of the desired sex. However, this process can negatively affect the quality of semen due to biochemical and physical stresses. ProAKAP4 is a major component of the sperm flagellum structure. In this study, sexed bull semen samples were evaluated using the proAKAP4 biomarker for the first time. Based on CASA and flow cytometry analysis of spermatozoa after thawing and incubation for 3 h, proAKAP4 is considered a practical biomarker for estimating the longevity of sexed sperm quality. ProAKAP4 is a sperm structural protein that regulates motility through the PKA-dependent cAMP signaling pathway, which is synthesized as an X chromosome-linked member of the gene family. This study aims to determine the optimal level of proAKAP4 for evaluating sexed semen through investigating its relationship with the longevity of sperm quality in sexed Holstein bull sperm. A total of 30 sexed sperm samples (bearing X chromosomes) from 30 distinct Holstein bulls (n = 30) were analyzed. The frozen bull sperm samples were assessed for their proAKAP4 levels, mitochondrial membrane potential, plasma membrane and acrosome integrity (PMAI), and spermatozoa movement parameters at hours 0 and 3 after thawing. The proAKAP4 levels in the sexed sperm samples ranged from 16.35 to 72.10 ng/10 M spz, with an average of 37.18 ± 15.1 ng/10 M spz. A strong positive correlation was observed between proAKAP4 levels and total motility, progressive motility, PMAI, high mitochondrial membrane potential, VAP, and VCL values after 3 h of incubation, when compared to post-thaw analyses. The results also reveal that spermatozoa with proAKAP4 levels of ≥40 ng/10 M spz exhibit higher quality. In conclusion, the level of proAKAP4 in sexed sperm aligns with previous studies and shows potential as a biomarker for assessing the longevity of sexed sperm quality. [ABSTRACT FROM AUTHOR]

The Koi fish (Cyprinus carpio var. koi) is an ornamental fish with a high selling value because of its attractive colors, color patterns, body shape, and swimming motion. Koi fish is extensively traded in the international fish market because of their popularity among hobbyists from numerous countries worldwide. This review discusses various aspects of Koi fish cultivation, including genetic involvement, selective breeding strategies, and management systems. By examining crucial factors such as water parameters, technological innovations, and evolving cultivation methods, this review explored their influence on the quality of Koi fish. Breakthrough technologies, such as ornamental fish warehousing and recirculation aquaculture systems, enhance breeding efficiency and profitability. Molecular sexing, feed optimization, and color enhancement strategies are central to pursuing superior Koi fish. Reproduction management, disease prevention, and risk reduction during transport underscore ongoing efforts to ensure their survival. Despite notable progress, several challenges remain, including limited genetic studies, gaps in disease research, and unexplored herbal alternatives. The active involvement of hobbyists and breeders in research initiatives is a pivotal force in unlocking the untapped potential. The holistic approaches to enhance production efficiency and improve care standards require further exploration, paving the way for a sustainable future in the evolving management of Koi fish cultivation. [ABSTRACT FROM AUTHOR]

1. Male and female Chukar partridges are difficult to differentiate based on their morphology or by the Chromobox-Helicase-DNA binding (CHD) during early growth. 2. The current study developed a novel, simple, low-cost and rapid sexing protocol for Chukar partridges based on the newly defined sexing gene ubiquitin-associated protein 2 (UBAP2). 3. The length of polymorphism between UBAP2-W and UBAP2-Z homologous genes allows for easy sex discrimination in this species. Molecular sexing analysis was based on the simultaneous amplification of both genes, resulting in two distinct amplicons (947 bp and 535 bp) in heterogametic females and only a single band (535 bp) in homogametic males, which is easy to detect with agarose gel electrophoresis. 4. This technique is simple and convenient for genetic sex determination in Chukar partridges. [ABSTRACT FROM AUTHOR]

Since the commercial beginning of sperm sexing in artificial insemination, the adoption of this technology by the livestock industry (producers, veterinarians, and genetics companies) has been a reality in cattle production, mainly in dairy cattle. This review describes the beginnings of sperm sexing, its development, commercial application, and evolution to the present. The most significant events were undoubtedly the determination of the difference in DNA content between spermatozoa carrying the "Y" or "X" chromosome, the flow of these in the cytometer, and their separation into the so-called "Y" and "X" spermatozoa. The subsequent achievements that favored the application of this technology commercially were the determination of the optimal concentration and the successful cryopreservation of sexed semen; since then, research to try to reduce the deleterious effects of the sexing process has not stopped, leading to the emergence of new sperm sexing technologies where this effect is minimal. The most widely used technique commercially is the ultrasexing of 4 million spermatozoa (SexedULTRA-4M™), in which the method, media, and cytometers were completely modified so that this technology has results very similar to those obtained with unsexed semen (conventional semen). There is another sperm sexing technology called Sexcel™ that is offered commercially, in which they have obtained similar results to those obtained with conventional semen, but only in heifers. With these advances, sperm sexing is shown to be a technology in constant development and of high impact on cattle farming. [ABSTRACT FROM AUTHOR]

Sex determination in monomorphic birds is a precondition for captive breeding programs and management and conservation strategies for threatened species. Most species of the order Psittaciformes often present complications since these birds lack external sexual phenotypic traits, making it impossible to differentiate males and females. In the present study, we used molecular techniques to determine the sex of 31 individuals belonging to nine species of the order Psittaciformes kept under human care at the Akumal Monkey Sanctuary & Rescued Animals in Quintana Roo, Mexico. This is a useful and low-cost methodology based on the analysis of the conserved region of the CHD1 gene, which was amplified by PCR with two sets of primers: P8/P2 and 2550F/2718 R. All individuals were successfully sexed with the first set of primers, while only 28 out of 31 samples (90%) could be amplified with the second set. Out of the 31 individuals analyzed, fifteen are female, and seventeen are male. This information represents a handy tool for adequately managing birds under human care, resulting in their reproduction and eventual reintegration into their natural habitat. [ABSTRACT FROM AUTHOR]

Sex determination by DNA-based molecular techniques in Sumatran tigers needs to be investigated and developed for forensic and population genetic purposes. The amelogenin gene is a marker commonly used for sex determination. In some species, the difference between the AMELX and AMELY sequences has been reported to be in the intron region. However, the difference between the AMELX and AMELY sequences in the Sumatran tiger is unknown. Therefore, it is necessary to investigate the sequence differences in introns between AMELX and AMELY Sumatran tigers to determine the specific differences between male and female samples. This study aimed to analyse the sequence of nucleotide bases in the Sumatran tiger amelogenin gene introns based on the nucleotide base sequences in the amelogenin gene introns. The method in this research is descriptive, with a molecular observation of the AMELX and AMELY Sumatran tiger sequences. The amplified samples were sequenced, and it was found that the lengths of the AMELX and AMELY Sumatran tiger sequences were 215 bp and 194 bp, respectively, with a 21 bp deletion in the AMELY sequence. [ABSTRACT FROM AUTHOR]

Simple Summary: A lot of avian species are morphologically monomorphic, and thus, sex determination is difficult if it is based only on their external examination. Molecular sex identification has become a crucial tool in various fields of biology, including ornithology. This non-invasive method used to determine the genetic sex of birds of any age, in our case, Eudromia elegans (Paleognathae, Tinamiformes), can proceed with regard to the differences between avian male (ZZ) and female (ZW) chromosomes. According to our experience, the other molecular methods failed in the sex determination of this exact species. The new test was designed to be reliable, fast, and simple to determine the sex of the individuals of E. elegans. Molecular sexing has significant implications for understanding various aspects of its biology, including mating systems, population genetics, and conservation strategies. By accurately determining the sex of individuals within a population, researchers can investigate sex ratio patterns, reproductive success, and gene flow. Sex determination based just on morphological traits such as plumage dichromatism, sexual size dimorphism, behavior, or vocalizations is really challenging because of the sexual monomorphism present in more than half of avian species. Currently, a lot of them can be tested through DNA-based procedures, but they do not fit all the avian species, such as Eudromia elegans. The aim of this study was to design a new molecular method suitable for routine sex determination for that species that is fast, simple, and cost- and time- effective. DNA was isolated from dry blood stain and/or chest feather samples of E. elegans species. We used two sets of sex-specific primers (ZF/ZR and WF/WR) to amplify the expected fragments localized on the highly conserved CHD1 gene to distinguish between sexes due to the W-specific DNA sequence present only in females. We confirmed the accuracy and consistency of the PCR-based method based on length differences to distinguish between the sexes of E. elegans, which amplified two fragments in females and one fragment in males. [ABSTRACT FROM AUTHOR]

The Great Knot is a species from the Scolopacidae family of waders migrating within the East Asian-Australasian Flyway, and studies on this species have contributed greatly to understanding of migration ecophysiology and migration strategies in long-distance migrants. In this paper, we provide the first description of biometric variability and sexual size dimorphism in Great Knots. During the study on the Kamchatka Peninsula, 683 adults and 229 juveniles were measured and sexed molecularly. In adults, the mean measurements of females were larger than in males, except for tarsus length. In juveniles, at the early stage of migration from breeding to wintering grounds, apparently growth was not complete. Sexual dimorphism was small, with only wing length being significantly longer in females than in males. All dimensions of juveniles were smaller than those of adults, especially in bill length. The most sexually dimorphic trait in both adults and juveniles was wing length, and the most effective discriminant function with wing length as a single predictor correctly identified the sex of 76% of birds in both age classes. However, molecular sexing is the method of choice for reliable sexing, especially in juveniles. [ABSTRACT FROM AUTHOR]

The ability to sex individuals is an important component of many behavioural and ecological investigations and provides information for demographic models used in conservation and species management. However, many birds are difficult to sex using morphological characters or traditional molecular sexing methods. In this study, we developed probabilistic models for sexing birds using quantitative PCR (qPCR) data. First, we quantified distributions of gene copy numbers at a set of six sex‐linked genes, including the sex‐determining gene DMRT1, for individuals across 17 species and seven orders of birds (n = 150). Using these data, we built predictive logistic models for sex identification and tested their performance with independent samples from 51 species and 13 orders (n = 209). Models using the two loci most highly correlated with sex had greater accuracy than models using the full set of sex‐linked loci, across all taxonomic levels of analysis. Sex identification was highly accurate when individuals to be assigned were of species used in model building. Our analytical approach was widely applicable across diverse neognath bird lineages spanning millions of years of evolutionary divergence. Unlike previous methods, our probabilistic framework incorporates uncertainty around qPCR measurements as well as biological variation within species into decision‐making rules. We anticipate that this method will be useful for sexing birds, including those of high conservation concern and/or subsistence value, that have proven difficult to sex using traditional approaches. Additionally, the general analytical framework presented in this paper may also be applicable to other organisms with sex chromosomes. [ABSTRACT FROM AUTHOR]

South Africa is home to numerous indigenous and locally developed sheep (Nguni Pedi, Zulu, and Namaqua Afrikaner, Afrino, Africander, Bezuidenhout Africander, Damara, Dorper, Döhne Merino, Meat Master, South African Merino, South African Mutton Merino, Van Rooy, and Dorper), goat (SA veld, Tankwa, Imbuzi, Bantu, Boer, and Savanna) and cattle (Afrigus, Afrikaner, Bolowana, Bonsmara, Bovelder, Drakensberger, South African Angus, South African Dairy Swiss, South African Friesland, South African Red, and Veld Master) animals. These breeds require less veterinary service, feed, management efforts, provide income to rural and or poor owners. However, most of themare under extinction risks and some with unknown status hence, require immediate conservation intervention. To allow faster genetic progress on the endangered animals, it is important to generate productive animals while reducing wastages and this can be achieved through sex-sorted semen. Therefore, this systematic review is aimed to evaluate the prospects of X and Y-sexed semen in ruminant livestock and some solutions that can be used to address poor sex-sorted semen and its fertility. This review was incorporated through gathering and assessing relevant articles and through the data fromthe DAD-IS database. The keywords that were used to search articles online were pre-gender selection, indigenous ecotypes, fertility, flow cytometry, artificial insemination, conservation, and improving sexed semen. Following a careful review of all articles, PRISMA guidelines were used to find the articles that are suitable to address the aim of this review. Sex-sorted semen is a recently introduced technology gaining more attention from researchers particularly, in the conservation programs. Preselection of semen based on the sex chromosomes (X- and or Y-bearing chromosomes) is of paramount importance to obtain desired sex of the offspring and avoid animal wastage as much as possible. However, diverse factors can affect quality of semen of different animal species especially after sex-sorting. Flow cytometry is a common method used to select male and female sperm cells and discard dead and abnormal sperm cells during the process. Thus, sperm sexing is a good advanced reproductive technology (ART) however, it is associated with the production of oxidative stress (OS) and DNA fragmentation (SDF). These findings, therefore, necessitates more innovation studies to come up with a sexing technology that will protect sperm cell injuries during sorting in frozen-thawed. [ABSTRACT FROM AUTHOR]

Background: Recently implemented research policies requiring the inclusion of females and males have created an urgent need for effective training in how to account for sex, and in some cases gender, in biomedical studies. Methods: Here, we evaluated three sets of publicly available online training materials on this topic: (1) Integrating Sex & Gender in Health Research from the Canadian Institutes of Health Research (CIHR); (2) Sex as a Biological Variable: A Primer from the United States National Institutes of Health (NIH); and (3) The Sex and Gender Dimension in Biomedical Research, developed as part of "Leading Innovative measures to reach gender Balance in Research Activities" (LIBRA) from the European Commission. We reviewed each course with respect to their coverage of (1) What is required by the policy; (2) Rationale for the policy; (3) Handling of the concepts "sex" and "gender;" (4) Research design and analysis; and (5) Interpreting and reporting data. Results: All three courses discussed the importance of including males and females to better generalize results, discover potential sex differences, and tailor treatments to men and women. The entangled nature of sex and gender, operationalization of sex, and potential downsides of focusing on sex more than other sources of variation were minimally discussed. Notably, all three courses explicitly endorsed invalid analytical approaches that produce bias toward false positive discoveries of difference. Conclusions: Our analysis suggests a need for revised or new training materials that incorporate four major topics: precise operationalization of sex, potential risks of over-emphasis on sex as a category, recognition of gender and sex as complex and entangled, and rigorous study design and data analysis. Plain english summary: Recently implemented research policies requiring the inclusion of females and males have created an urgent need for effective training in how to account for sex, and in some cases gender, in biomedical studies. We evaluated three publicly available online trainings on this topic: (1) Integrating Sex & Gender in Health Research from the Canadian Institutes of Health Research; (2) Sex as a Biological Variable: A Primer from the United States National Institutes of Health; and (3) The Sex and Gender Dimension in Biomedical Research, developed as part of "Leading Innovative Measures to Reach Gender Balance in Research Activities (LIBRA)" from the European Commission. We reviewed each course with respect to their coverage of (1) What is required by the policy; (2) Rationale for the policy; (3) Handling of the concepts "sex" and "gender;" (4) Research design and analysis; and (5) Interpreting and reporting data. All three discussed the importance of including males and females to better generalize results, discover potential sex differences, and tailor treatments to men and women. The interconnectedness of sex and gender, how to operationalize sex, and potential downsides of focusing on sex more than other sources of variation were minimally discussed. Notably, all three courses explicitly endorsed invalid analytical approaches that lead to incorrect findings of differences. Our analysis suggests a need for revised or new training materials that cover four major topics: precise operationalization of sex, attention to potential risks of over-emphasizing sex, consideration of gender and sex as complex and intertwined, and rigorous study design and data analysis. Highlights: Three major online trainings on implementing sex and gender research policies from Canada, the United States, and the European Union covered much of the same content. A common theme among the trainings was the importance of including males and females to better generalize results, discover potential sex differences, and tailor treatments to men and women. Topics that were not substantially addressed in the trainings included the extent to which sex and gender are inextricably entangled, the operationalization of sex using concrete, measurable variables, and the potential risks of focusing on sex more than other sources of variation. All three courses explicitly endorsed invalid analytical approaches that produce bias toward false positive discoveries of difference. Key areas for improved or new materials are: precise operationalization of sex, attention to the downsides of over-emphasis on sex as a category, recognition of gender and sex as complex and entangled entities, and rigorous study design and data analysis. [ABSTRACT FROM AUTHOR]

To understand the biology of a species, it is often crucial to be able to differentiate males and females. However, many species lack easily identifiable sexually dimorphic traits. In those that possess sex chromosomes, molecular sexing offers a good alternative, and molecular sexing assays can be developed through the comparison of male and female genomic sequences. However, in many nonmodel species, sex chromosomes are poorly differentiated, and identifying sex-linked sequences and developing sexing assays can be challenging. In this study, we highlight a simple transcriptome-based procedure for the detection of sex-linked markers suitable for the development of sexing assays that circumvents limitations of more commonly used approaches. We apply it to the spotted snow skink Carinascincus ocellatus , a viviparous lizard with homomorphic XY chromosomes that has environmentally induced sex reversal. With transcriptomes from three males and three females alone, we identify thousands of putative Y-linked sequences. We confirm linkage through alignment of assembled transcripts to a distantly related lizard genome and readily design multiple single locus polymerase chain reaction primers to sex C. ocellatus and related species. Our approach also facilitates valuable comparisons of sex determining systems on a broad taxonomic scale. [ABSTRACT FROM AUTHOR]

Cancer survivors may experience long-term cardiovascular complications due to chemotherapeutic drugs such as doxorubicin (DOX). The exact mechanism of delayed DOX-induced cardiotoxicity has not been fully elucidated. Sex is an important risk factor for DOX-induced cardiotoxicity. In the current study, we identified sex differences in delayed DOX-induced cardiotoxicity and determined the underlying molecular determinants of the observed sexual dimorphism. Five-week-old male and female mice were administered intraperitoneal injections of DOX (4 mg/kg/week) or saline for 6 weeks. Echocardiography was performed 5 weeks after the last dose of DOX to evaluate cardiac function. Thereafter, mice were sacrificed and gene expression of markers of apoptosis, senescence, and inflammation was measured by PCR in hearts and livers. Proteomic profiling of the heart from both sexes was conducted to determine differentially expressed proteins (DEPs). Only DOX-treated male, but not female, mice demonstrated cardiac dysfunction, cardiac atrophy, and upregulated cardiac expression of Nppb and Myh7. No sex-related differences were observed in DOX-induced expression of most apoptotic, senescence, and pro-inflammatory markers. However, the gene expression of Trp53 was significantly reduced in hearts of DOX-treated female mice only. The anti-inflammatory marker Il-10 was significantly reduced in hearts of DOX-treated male mice only, while the pro-inflammatory marker Il-1α was significantly reduced in livers of DOX-treated female mice only. Gene expression of Tnf-α was reduced in hearts of both DOX-treated male and female mice. Proteomic analysis identified several DEPs after DOX treatment in a sex-specific manner, including anti-inflammatory acute phase proteins. This is the first study to assess sex-specific proteomic changes in a mouse model of delayed DOX-induced cardiotoxicity. Our proteomic analysis identified several sexually dimorphic DEPs, many of which are associated with the anti-inflammatory marker Il-10. [ABSTRACT FROM AUTHOR]

The identification of sex‐linked scaffolds and the genetic sex of individuals, i.e. their sex karyotype, is a fundamental step in population genomic studies. If sex‐linked scaffolds are known, single individuals may be sexed based on read counts of next‐generation sequencing data. If both sex‐linked scaffolds as well as sex karyotypes are unknown, as is often the case for non‐model organisms, they have to be jointly inferred. For both cases, current methods rely on arbitrary thresholds, which limits their power for low‐depth data. In addition, most current methods are limited to euploid sex karyotypes (XX and XY). Here we develop BeXY, a fully Bayesian method to jointly infer the posterior probabilities for each scaffold to be autosomal, X‐ or Y‐linked and for each individual to be any of the sex karyotypes XX, XY, X0, XXX, XXY, XYY and XXYY. If the sex‐linked scaffolds are known, it also identifies autosomal trisomies and estimates the sex karyotype posterior probabilities for single individuals. As we show with downsampling experiments, BeXY has higher power than all existing methods. It accurately infers the sex karyotype of ancient human samples with as few as 20,000 reads and accurately infers sex‐linked scaffolds from data sets of just a handful of samples or with highly imbalanced sex ratios, also in the case of low‐quality reference assemblies. We illustrate the power of BeXY by applying it to both whole‐genome shotgun and target enrichment sequencing data of ancient and modern humans, as well as several non‐model organisms. [ABSTRACT FROM AUTHOR]

Transgenic insect strains with tetracycline repressible (Tet-Off) female-lethal genes provide significant advantages over traditional sterile insect techniques for insect population control, such as reduced diet and labor costs and more efficient population suppression. Tet-Off systems are suppressed by tetracycline-class antibiotics, most commonly tetracycline (Tc) or doxycycline (Dox), allowing for equal sex ratio colonies of transgenic insects when reared with Tc or Dox and male-only generations in their absence. Dox is a more stable molecule and has increased uptake than Tc, which could be advantageous in some insect mass-rearing systems. Here, we evaluated the suitability of Dox for rearing Tet-Off female-lethal strains of Australian sheep blowfly, Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae), and New World screwworm, Cochliomyia hominivorax (Coquerel, 1858) (Diptera: Calliphoridae), and the effects of dosage on strain performance. For both species, colonies were able to be maintained with mixed-sex ratios at much lower dosages of Dox than Tc. Biological yields of C. hominivorax on either antibiotic were not significantly different. Reduction of Dox dosages in C. hominivorax diet did not affect biological performance, though rearing with 10 or 25 μg/mL was more productive than 50 μg/mL. Additionally, C. hominivorax mating performance and longevity were equal on all Dox dosages. Overall, Dox was a suitable antibiotic for mass-rearing Tet-Off female-lethal L. cuprina and C. hominivorax and was functional at much lower dosages than Tc. [ABSTRACT FROM AUTHOR]

The Long-eared Owl (Asio otus) is one of few owl species with sexually dimorphic plumage coloration, with males displaying a light phenotype and females displaying a dark phenotype. This dichromatism can be a useful tool for sexing these owls in the field; however, we observed that some individuals display an intermediate phenotype, which is neither distinctly light nor dark and limits confidence in identifying sex. In this study, we used plumage coloration of the underwing, face, and legs to predict the sex of Long-eared Owls banded during spring migration at Whitefish Point, Michigan, USA, from 2016 to 2022 (n = 1967) and summarized differences between measurements of size such as body mass, wing length, and tail length among the three phenotypes. We found that Long-eared Owls with light plumage (classified as male) were the smallest, owls with dark plumage (classified as female) were the largest, and owls with intermediate plumage (classified as unknown sex) were intermediate in size. Using molecular sexing on a subsample of these owls (n = 116), we found that only 1 of 76 (1.3%) owls with light or dark plumage had its sex incorrectly predicted using plumage color, and of the 40 unknown sex individuals with intermediate plumage, 35 (87.5%) were female and 5 (12.5%) were male. This study reinforces previous findings that distinctly light or dark plumage is a reliable indicator of sex in Long-eared Owls, and provides new evidence that Long-eared Owls with intermediate plumage are likely small females but may also be large males. We conclude that Long-eared Owls migrating through the Great Lakes region of the United States display significant differences in both size and plumage between the sexes, and that these two measures of dimorphism are correlated. Asio otus es una de las pocas especies de búhos con una coloración del plumaje con dimorfismo sexual, donde los machos muestran un fenotipo claro y las hembras muestran un fenotipo oscuro. Este dicromatismo puede ser una herramienta útil para determinar el sexo de estos búhos en el campo; sin embargo, observamos que algunos individuos muestran un fenotipo intermedio, que no es distintivamente claro ni oscuro, lo que limita la confianza en la identificación del sexo. En este estudio, utilizamos la coloración del plumaje de la parte inferior del ala, la cara y las patas para predecir el sexo de individuos de A. otus anillados durante la migración de primavera en Whitefish Point, Michigan, EEUU, de 2016 a 2022 (n = 1967) y resumimos las diferencias entre las medidas de tamaño, como masa corporal, longitud de las alas y longitud de la cola, entre los tres fenotipos. Descubrimos que los individuos de A. otus con plumaje claro (clasificados como machos) eran los más pequeños, los individuos con plumaje oscuro (clasificados como hembras) eran los más grandes, y los individuos con plumaje intermedio (clasificados como sexo desconocido) tenían un tamaño intermedio. Utilizando determinación molecular del sexo en una sub-muestra de estos búhos (n = 116), encontramos que solo 1 de 76 (1.3%) búhos con plumaje claro u oscuro tuvo su sexo incorrectamente predicho utilizando el color del plumaje, y de los 40 individuos de sexo desconocido con plumaje intermedio, 35 (87.5%) eran hembras y 5 (12.5%) eran machos. Este estudio refuerza hallazgos previos de que un plumaje distintivamente claro u oscuro es un indicador confiable del sexo en A. otus y proporciona nueva evidencia de que los individuos de A. otus con plumaje intermedio son probablemente hembras pequeñas, pero también pueden ser machos grandes. Concluimos que los individuos de A. otus que migran a través de la región de los Grandes Lagos en los Estados Unidos muestran diferencias significativas tanto en tamaño como en plumaje entre los sexos, y que estas dos medidas de dimorfismo están correlacionadas. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

BACKGROUND: Mythimna loreyi is an important agricultural pest with a sensitive sex pheromone communication system. To clarify the pheromone binding proteins (PBPs) and pheromone receptors (PRs) involved in sex pheromone perception is important for both understanding the molecular olfactory mechanism and developing a new pest control strategy in M. loreyi. RESULTS: First, the electroantennogram (EAG) assay showed that male M. loreyi displayed the highest response to the major sex pheromone component Z9‐14:Ac, and higher responses to two minor components, Z7‐12:Ac and Z11‐16:Ac. Second, the fluorescence competition binding assay showed that PBP1 bound all three pheromones and other tested compounds with high or moderate affinity, while PBP2 and PBP3 each bound only one pheromone component and few other compounds. Third, functional study using the Xenopus oocyte system demonstrated that, of the six candidate PRs, PR2 was weakly sensitive to the major pheromone Z9‐14:Ac, but was strongly sensitive to pheromone analog Z9‐14:OH; PR3 was strongly and specifically sensitive to a minor component Z7‐12:Ac; PR4 and OR33 were both weakly sensitive to another minor component, Z11‐16:Ac. Finally, phylogenetic relationship and ligand profiles of PRs were compared among six species from two closely related genera Mythimna and Spodoptera, suggesting functional shifts of M. loreyi PRs toward Spodoptera PRs. CONCLUSION: Functional differentiations were revealed among three PBPs and six PRs in sex pheromone perception, laying an important basis for understanding the molecular mechanism of sex pheromone perception and for developing new control strategies in M. loreyi. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: Due to limited proteomic data for rabbit spermatozoa and less comprehensive databases compared to humans, we conducted a combined bioinformatic analysis of the proteome of rabbit X (RX) and human X and Y (HX and HY) chromosomes to identify membrane-associated proteins, particularly those accessible from the cell surface, for potential applications in sperm sexing techniques. Our analysis found 100 (RX), 211 (HX), and 3 (HY) plasma membrane or cell surface-associated proteins, of which 61, 132, and 3 are potentially accessible from the cell surface. Notably, among the HX targets, 60 could serve as additional RX targets not previously identified, bringing the total to 121 RX targets. Furthermore, at least 53 out of the 114 potential common HX and RX targets chromosomes have been previously identified in human spermatozoa, emphasizing their potential as targets of X-chromosome-bearing spermatozoa. The utility of these proteins as targets of rabbit X-chromosome-bearing spermatozoa warrants further exploration. Studying proteins associated with sex chromosomes can provide insights into sex-specific proteins. Membrane proteins accessible through the cell surface may serve as excellent targets for diagnostic, therapeutic, or even technological purposes, such as sperm sexing technologies. In this context, proteins encoded by sex chromosomes have the potential to become targets for X- or Y-chromosome-bearing spermatozoa. Due to the limited availability of proteomic studies on rabbit spermatozoa and poorly annotated databases for rabbits compared to humans, a bioinformatic analysis of the available rabbit X chromosome proteome (RX), as well as the human X (HX) and Y (HY) chromosomes proteome, was conducted to identify potential targets that could be accessible from the cell surface and predict which of the potential targets identified in humans might also exist in rabbits. We identified 100, 211, and 3 proteins associated with the plasma membrane or cell surface for RX, HX, and HY, respectively, of which 61, 132, and 3 proteins exhibit potential as targets as they were predicted to be accessible from the cell surface. Cross-referencing the potential HX targets with the rabbit proteome revealed an additional 60 proteins with the potential to be RX targets, resulting in a total of 121 potential RX targets. In addition, at least 53 possible common HX and RX targets have been previously identified in human spermatozoa, emphasizing their potential as targets of X-chromosome-bearing spermatozoa. Further proteomic studies on rabbit sperm will be essential to identify and validate the usefulness of these proteins for application in rabbit sperm sorting techniques as targets of X-chromosome-bearing spermatozoa. [ABSTRACT FROM AUTHOR]

Macrobrachium nipponense is gonochoristic and sexually dimorphic. The male prawn grows faster and usually has a larger size than the female. Therefore, a higher male proportion in stock usually results in higher yield. To investigate the impact of temperature on sexual differentiation in M. nipponense, two temperature treatments (26 °C and 31 °C) were conducted. The results showed that compared to the 31 °C treatment (3.20 ± 0.12), the 26 °C treatment displayed a lower female/male ratio (2.20 ± 0.11), which implied that a lower temperature could induce masculinization in M. nipponense. The temperature-sensitive sex differentiation phase was 25–35 days post hatching (DPH) at 26 °C while 15–20 DPH at 31 °C. Transcriptome and qPCR analysis revealed that a lower temperature up-regulated the expression of genes related to androgen secretion, and down-regulated the expressions of genes related to oogonia differentiation. Thirty-one temperature-regulated sex-differentiation genes were identified and the molecular mechanism of temperature-regulated sex differentiation was suggested. The finding of this study indicates that temperature regulation can be proposed as an innovative strategy for improving the culture yield of M. nipponense. [ABSTRACT FROM AUTHOR]

Psittacine beak and feather disease virus (PBFDV) is a significant viral pathogen affecting the development of beak and feather cells, leading to feather abnormalities in avian species. This study aimed to investigate the molecular detection rate of PBFDV among Psittaciformes in Iran and to evaluate the influence of factors such as sex, species, season, and bird origin on PBFDV prevalence. Feather samples were collected from 1335 Psittaciformes, including Agapornis roseicollis, Pyrrhura molinae, Myiopsitta monachus, Aratinga solstitialis, Nymphicus hollandicus, Psittacula krameri, Psittacus erithacus, Poicephalus senegalus, Eos bornea, and Agapornis fischeri, and subjected to polymerase chain reaction (PCR) for PBFDV detection. The overall PBFDV detection rate across all species was 56.2% (751/1335, 95% CI: 53.6%-58.9%). The results showed that Agapornis roseicollis had a 2.23-fold higher likelihood of PBFDV infection compared to the reference species, Myiopsitta monachus (95% CI: 1.36-3.66). Furthermore, a significant interaction effect between season and species was observed. During autumn, Aratinga solstitialis and Pyrrhura molinae were 10.00 (95% CI: 5.10-20.59) and 3.72 (95% CI: 2.28-6.08) times more likely to be infected with PBFDV compared to spring, respectively. These findings underscore a high prevalence of PBFDV in Iran's psittacine population. The study emphasizes the importance of such investigations and the exploration of various risk factors for disease control and prevention strategies. It also underscores the necessity of virological assessments prior to bird export and import. [ABSTRACT FROM AUTHOR]

Brain‐derived extracellular vesicles (EVs) play an active role in Alzheimer's disease (AD), relaying important physiological information about their host tissues. The internal cargo of EVs is protected from degradation, making EVs attractive AD biomarkers. However, it is unclear how circulating EVs relate to EVs isolated from disease‐vulnerable brain regions. We developed a novel method for collecting EVs from the hippocampal interstitial fluid (ISF) of live mice. EVs (EVISF) were isolated via ultracentrifugation and characterized by nanoparticle tracking analysis, immunogold labelling, and flow cytometry. Mass spectrometry and proteomic analyses were performed on EVISF cargo. EVISF were 40–150 nm in size and expressed CD63, CD9, and CD81. Using a model of cerebral amyloidosis (e.g., APPswe, PSEN1dE9 mice), we found protein concentration increased but protein diversity decreased with Aβ deposition. Genotype, age, and Aβ deposition modulated proteostasis‐ and immunometabolic‐related pathways. Changes in the microglial EVISF proteome were sexually dimorphic and associated with a differential response of plaque associated microglia. We found that female APP/PS1 mice have more amyloid plaques, less plaque associated microglia, and a less robust‐ and diverse‐ EVISF microglial proteome. Thus, in vivo microdialysis is a novel technique for collecting EVISF and offers a unique opportunity to explore the role of EVs in AD. [ABSTRACT FROM AUTHOR]

The sex of the animals is of paramount importance in many animal production systems. This is particularly evident in the production of milk or in breeding programs focused on the production of female animals. In some cases, slaughter or euthanasia of animals of the unwanted sex becomes the only solution, highlighting ethical and economic concerns. As global demand for food continues to rise, the importance of addressing these issues becomes more evident. Reproductive technologies, such as sperm sexing techniques, may hold the key to addressing both animal welfare and the sustainability of animal production. The use of semen enriched with sperm capable of producing offspring of the desired sex can serve as a valuable tool for producers to exert greater control over production outcomes, not only helping to mitigate welfare issues related to the unnecessary premature death of unwanted offspring but also providing a possible ally in the face of stricter animal welfare guidelines. In addition, sexed semen can also contribute to financial gains and reduce greenhouse gas emissions and food waste associated with the less profitable part of the herd. This paper explores the positive impacts that sperm sexing can have on animal welfare, economy, and environment. It also discusses currently available options and strategies for more successful implementation of sexed semen. Partnerships between companies and scientists will be essential to find innovative ways to adapt current production systems and develop sperm sexing technologies that apply to most livestock industries. [ABSTRACT FROM AUTHOR]

• Mice lacking cyclooxygenase 2 enzyme had abnormal microglia morphology. • Microglia changes were sex-, brain region-, and stage- dependent. • Cyclooxygenase 2 knockin mice had increased microglia density and branch length. • Abnormal percentage of amoeboid and ramified microglia was also observed. • Males show more widespread changes compare to females. Prostaglandin E2 (PGE2) is a signaling molecule produced by cyclooxygenase-2 (COX-2) that is important in healthy brain development. Anomalies in the COX-2/PGE2 pathway due to genetic or environmental factors have been linked to Autism Spectrum Disorders (ASD). Our previous studies showed that COX-2 deficient (COX-2−KI) mice exhibit sex-dependent molecular changes in the brain and associated autism-related behaviors. Here, we aim to determine the effect of COX-2−KI on microglial density and morphology in the developing brain. Microglia normally transition between an amoeboid or ramified morphology depending on their surroundings and are important for the development of the healthy brain, assisting with synaptogenesis, synaptic pruning, and phagocytosis. We use COX-2−KI male and female mice to evaluate microglia density, morphology, and branch length and number in five brain regions (cerebellum, hippocampus, olfactory bulb, prefrontal cortex, and thalamus) at the gestational day 19 (G19) and postnatal day 25 (PN25). We discovered that COX2−KI females were affected at G19 with increased microglial density, altered percentage of amoeboid and ramified microglia, affected branch length, and decreased branching networks in a region-specific manner; these effects persisted to PN25 in select regions. Interestingly, while limited changes were found in G19 COX-2−KI males, at PN25 we found increased microglial density, higher percentages of ramified microglia, and increased branch counts, and length observed in nearly all brain regions tested. Overall, we show for the first time that the COX-2 deficiency in our ASD mouse model influences microglia morphology in a sex- and region- and stage-dependent manner. [ABSTRACT FROM AUTHOR]

Substantial evidence highlights divergences in immune responses between men and women. Women are more susceptible to autoimmunity, whereas men suffer from the more severe presentation of autoimmune disorders. The molecular mechanism of this sexual dimorphism remains elusive. Herein, we conducted a comprehensive analysis of sex differences in whole-blood gene expression focusing on alternative splicing (AS) events in systemic lupus erythematosus (SLE), which is a prototype sex-biased disease. This study included 79 SLE patients with active disease and 58 matched healthy controls who underwent whole-blood RNA sequencing. Sex differences in splicing events were widespread, existent in both SLE and a healthy state. However, we observed distinct gene sets and molecular pathways targeted by sex-dependent AS in SLE patients as compared to healthy subjects, as well as a notable sex dissimilarity in intron retention events. Sexually differential spliced genes specific to SLE patients were enriched for dynamic cellular processes including chromatin remodeling, stress and inflammatory responses. Remarkably, the extent of sexual differences in AS in the SLE patients and healthy individuals exceeded those in gene expression. Overall, this study reveals an unprecedent variation in sex-dependent splicing events in SLE and the healthy state, with potential implications for understanding the molecular basis of sexual dimorphism in autoimmunity. [ABSTRACT FROM AUTHOR]

Tephritid fruit fly pests pose an increasing threat to the agricultural industry due to their global dispersion and a highly invasive nature. Here we showcase the feasibility of an early-detection SEPARATOR sex sorting approach through using the non-model Tephritid pest, Ceratitis capitata. This system relies on female-only fluorescent marker expression, accomplished through the use of a sex-specific intron of the highly-conserved transformer gene from C. capitata and Anastrepha ludens. The herein characterized strains have 100% desired phenotype outcomes, allowing accurate male–female separation during early development. Overall, we describe an antibiotic and temperature-independent sex-sorting system in C. capitata, which, moving forward, may be implemented in other non-model Tephritid pest species. This strategy can facilitate the establishment of genetic sexing systems with endogenous elements exclusively, which, on a wider scale, can improve pest population control strategies like sterile insect technique. [ABSTRACT FROM AUTHOR]

Simple Summary: Over 50% of birds are monomorphic, showing no sexually dimorphic traits, and in nestlings, the percentage is even higher. Early sex determination can be of great value in the management of wild birds, breeding of different bird species, improvement of breeding programs of captive birds, and evolutionary studies fields, and also for bird owners. In this study, we performed molecular sexing of wild and companion birds from various orders, such as Falconiformes, Accipitriformes, Galliformes, Anseriformes, Passeriformes, and Psittaciformes. Samples of oral swabs, feathers, and blood were collected from 43 birds. Conventional PCR was used to amplify the CHD1-Z and CHD1-W genes. The obtained results show that all types of samples can be used for molecular sexing of the studied species of birds. In conclusion, instead of using blood samples, our recommendation is to use minimally invasive samples (oral swabs and feathers) and test both types of samples on each bird. Birds are highly social and must be paired in order to increase their welfare. Most bird species are monomorphic; therefore, molecular sexing helps provide appropriate welfare for birds. Moreover, early sex determination can be of great value for bird owners. The aim of this study was to demonstrate that sex identification in birds achieved using molecular methods and samples collected via minimally invasive methods is fast, efficient, and accurate. A total of 100 samples (29 paired samples of feathers and oral swabs and 14 tripled samples of feathers, oral swabs, and blood) from 43 birds were included in this study, as follows: wild birds (Falconiformes, Accipitriformes, landfowl—Galliformes, waterfowl—Anseriformes) and companion birds (Passeriformes, Psittaciformes—large-, medium-, and small-sized parrots). Amplification of CHD1-Z and CHD1-W genes was performed via conventional PCR. The results obtained from feathers were compared to those obtained from oral swabs and to those obtained from blood samples, where applicable. The obtained results show that all types of samples can be used for molecular sexing of all studied bird species. To the best of our knowledge, the present study reports, for the first time, molecular sex identification in Red Siskin (Carduelis cucullata) and Goldfinch (Carduelis carduelis major). For higher accuracy, our recommendation is to use minimally invasive samples (oral swabs and feathers) and to test both types of samples for each bird instead of blood samples. [ABSTRACT FROM AUTHOR]

Single‐nucleotide polymorphism (SNP) analysis is a powerful tool for population genetics, pedigree reconstruction and phenotypic trait mapping. However, the untapped potential of SNP markers to discriminate the sex of individuals in species with reduced sexual dimorphism or of individuals during immature stages remains a largely unexplored avenue. Here, we developed a novel protocol for molecular sexing of birds based on the detection of unique Z‐ and W‐linked SNP markers. Our method is based on the identification of two unique loci, one in each sexual chromosome. Individuals are considered males when they show no calls for the W‐linked SNP and are heterozygous or homozygous for the Z‐linked SNP, while females exhibit both Z‐ and W‐linked SNP calls. We validated the method in the Jackdaw (Corvus monedula). The reduced sexual dimorphism in this species makes it difficult to identify the sex of individuals in the wild. We assessed the reliability of the method using 36 individuals of known sex and found that their sex was correctly assigned in 100% of cases. The sex‐linked markers also proved to be widely applicable for discriminating males and females from a sample of 927 genotyped individuals at different maturity stages, with an accuracy of 99.5%. Since SNP markers are increasingly used in quantitative genetic analyses of wild populations, the approach we propose has great potential to be integrated into broader genetic research programmes without the need for additional sexing techniques. [ABSTRACT FROM AUTHOR]

Major depressive disorder (MDD) is one of the most important causes of disability worldwide. While recent work provides insights into the molecular alterations in the brain of patients with MDD, whether these molecular signatures can be associated with the expression of specific symptom domains remains unclear. Here, we identified sex-specific gene modules associated with the expression of MDD, combining differential gene expression and co-expression network analyses in six cortical and subcortical brain regions. Our results show varying levels of network homology between males and females across brain regions, although the associations between these structures and the expression of MDD remain highly sex specific. We refined these associations to several symptom domains and identified transcriptional signatures associated with distinct functional pathways, including GABAergic and glutamatergic neurotransmission, metabolic processes and intracellular signal transduction, across brain regions associated with distinct symptomatic profiles in a sex-specific fashion. In most cases, these associations were specific to males or to females with MDD, although a subset of gene modules associated with common symptomatic features in both sexes were also identified. Together, our findings suggest that the expression of distinct MDD symptom domains associates with sex-specific transcriptional structures across brain regions. Recent research sheds light on sex-specific molecular changes in the brains of MDD patients, but their association with specific symptoms is still uncertain. Here, the authors revealed the existence of gene signatures underlying the expression of distinct symptom domains in the brain of men and women with depression. [ABSTRACT FROM AUTHOR]

Several approaches to sperm sexing such as Albumin gradient, Identification of H-Y antigen, Free-flow electrophoresis, Detection of sex-specific proteins, Centrifugal counter current distribution, Volumetric differences, Percoll density gradient, Flow-cytometry, Laser ablation, etc were put forward by the scientists. However, the alteration in DNA content between X- and Y-sperm remains the key and only discriminating feature for sperm sorting based on which only Flow cytometry and Laser ablation techniques are being used commercially. Flow cytometry is based on precise staining of the DNA of sperm with the nucleic acid-specific dye, Hoechst 33342, to differentiate between the subpopulations of X- and Y-sperm. The fluorescently stained sperm are then sex-sorted using a specialized highspeed sorter. Laser ablation (LA) is a system and method for sorting a mixture of stained particles in a fluid flow path. It includes an electromagnetic radiation source for exciting fluorescence emissions from the stained particles, a photodetector for detecting the fluorescence emissions, a processor for classifying the stained particles, and a photo-damaging laser for damaging selected particles in the flow path. [ABSTRACT FROM AUTHOR]

Idesia polycarpa is a dioecious tree; in field surveys, there are rare sex conversions in I. polycarpa individuals with bisexual flowers. To identify the molecular mechanisms underlying sex conversion in this species, an integrative analysis of the proteome and transcriptome profiles of I. polycarpa male and bisexual flowers at key developmental stages was conducted in this study using isobaric tags for relative and absolute quantification and RNA-seq technology. A total of 15,003 proteins were identified; the differentially expressed proteins (DEPs) were enriched in metabolic pathways, biosynthesis of secondary metabolites, and flavonoid metabolism pathways in all comparison groups. A total of 290,442 unigenes were obtained; these were compared with seven databases, revealing 196,366 annotated unigenes. In general, the expression of proteins and genes tended to be positively correlated, with Spearman correlation coefficients in the ranges of 0.152–0.262 (all genes and all proteins) and 0.497–0.778 (DEPs and DEGs). The integrative analysis of DEPs and DEGs between male and bisexual flowers revealed that the most significantly enriched pathways were flavonoid pathways, metabolic pathways, and the biosynthesis of secondary metabolites. Finally, four co-expressed proteins and transcripts and one gene associated with the flavonoid biosynthesis pathway were screened out. The proteins identified were p-coumaroyl shikimate 3′-hydroxylase, and shikimate/quinate hydroxycinnamoyl transferase, and the gene was caffeoyl-CoA O-methyltransferase. The analysis has revealed key potential proteins and genes involved in sex conversion at the molecular level and has provided a basis for future investigations of artificial regulation of sex differentiation in I. polycarpa. [ABSTRACT FROM AUTHOR]

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Taking advantage of the unique system of doubly uniparental inheritance (DUI) of mitochondria, we developed a reliable molecular method to sex individuals of the marine bivalve Macoma balthica rubra. In species with DUI (~100 known bivalves), both sexes transmit their mitochondria: males bear both a male‐ and female‐type mitogenome, while females bear only the female type. Male and female mitotypes are sufficiently divergent to reliably PCR‐amplify them specifically. Loop‐mediated isothermal amplification (LAMP) is a precise, economical and portable alternative to PCR for molecular sexing and we demonstrate its application in this context. We used 154 individuals sampled along the Atlantic coast of France and sexed microscopically by gonad examination to test for the congruence among gamete type, PCR sexing and LAMP sexing. We show an exact match among the sexing results from these three methods using the male and female mt‐cox1 genes. DUI can be disrupted in inter‐specific hybrids, causing unexpected distribution of mitogenomes, such as homoplasmic males or heteroplasmic females. To our knowledge, DUI disruption at the intra‐specific scale has never been tested. We applied our sexing protocol to control for unexpected heteroplasmy caused by hybridization between divergent genetic lineages and found no evidence of disruption in the mode of mitochondrial inheritance in M. balthica rubra. We propose LAMP as a useful tool to accelerate eco‐evolutionary studies of DUI. It offers the opportunity to investigate the potential role of, previously unaccounted‐for, sex‐specific patterns such as sexual selection or sex‐specific dispersal bias in the evolution of free‐spawning benthic species. [ABSTRACT FROM AUTHOR]

Sperm sexing is a technology that can generate great economic benefits in the animal production sector. Techniques such as sex-sorting promise over 90% accuracy in sperm sexing. However, for the correct standardization of the technique, some laboratory methodologies are required. The present manuscript describes in detail a standardized equine sperm sex-sorting protocol using an absolute qPCR-based methodology. Furthermore, the results of absolute qPCR were implemented and validated by generating equine/bovine heterologous embryos by intracytoplasmic sperm injection (ICSI) of presumably sexed equine spermatozoa into bovine oocytes using a piezoelectric system (Piezo-ICSI). Our results indicated that equine sex-sorting spermatozoa had a 97% and 94% certainty for X and Y sperm, respectively, while presumptive female and male equine/bovine hybrid embryos, generated by Piezo-ICSI, had an accuracy of 92% with respect to the desired sex. Therefore, it is concluded that the presented methodology is a reliable, cost-effective, and relatively simple option for standardizing sex-sorting of equine spermatozoa. This is supported by the results of the correct sexing of Piezo-ICSI heterologous embryos generated with the sexed spermatozoa, validating the correct sexing and viability of these gametes. [ABSTRACT FROM AUTHOR]

Small but robust differences in cognition exist between the sexes in adult populations. Studying sex differences in children's cognition can bring insight into when, where and how these differences might emerge in development. Here, we focus on differences in working memory because of its importance in underpinning a wide range of complex cognitive tasks and developmental outcomes for children. Using two levels of difficulty on a standard test of working memory (N-Back), data from 104 6- to 7-year-olds in Cuba showed that boys have quicker reaction times, but girls provide more accurate responses. With a comparable true positive rate between boys and girls, the sex differences in both accuracy and reaction times were limited to false-positive responses. Sex differences were consistent across levels of task difficulty and persisted after speed-accuracy trade-offs were considered. We argue that avoiding false positives requires a particularly strong role for inhibitory control and that this emerges in development according to a different maturational schedule for girls than it does for boys, underpinned by quantitative and qualitative differences in the development of brain areas that support this function. [ABSTRACT FROM AUTHOR]

Simple Summary: The rabbit production industry would greatly benefit from a technology that allows producers to obtain a more predominantly male or female offspring, accordingly to the goals of each production farm. Our review highlights the current and future developments in rabbit sperm sexing technologies, as well as the potential impact of implementing these methods in cuniculture. Given the remarkable technological progress made in recent years, there remains a pressing need for further research aimed at developing a cutting-edge technology that not only exhibits high efficiency but also offers cost-effectiveness, thus enabling its widespread adoption across the cuniculture industry. Sperm sex selection is a longstanding challenge in the field of animal reproduction. The cuniculture industry, in particular producers of males or females for breeding purposes, would greatly benefit from the pre-selection of the offspring's sex. This review article overviews the current and future developments in rabbit sperm sexing technologies, as well as the implications of implementing these methodologies in cuniculture. The first attempts of sperm sexing were performed in rabbits; however, a both efficient and cost-effective methodology was not yet developed for this species. Those included sperm sexing according to differences in sperm density, surface electric charge, pH susceptibility, antisera reaction, and flow cytometry. Separation by flow cytometry has proven to be efficient in rabbits, yielding fractions with approximately 81% and 86% purity for X- and Y-sperm, respectively. However, it is not cost-effective for cuniculture and decreases sperm quality. The advantages, limitations, and practical considerations of each method are presented, highlighting their applicability and efficiency. Furthermore, herein we explore the potential of immunological-based techniques that overcome some of the limitations of earlier methods, as well as recent advancements in sperm sexing technologies in other animal models, which could be applied to rabbits. Finally, the challenges associated with the development and widespread implementation of rabbit sperm sexing technologies are addressed. By understanding the advantages and limitations of existing and emerging methods, researchers can direct their efforts towards the most promising directions, ultimately contributing to a more efficient, profitable, and sustainable cuniculture. [ABSTRACT FROM AUTHOR]

Glial Fibrillary Acidic Protein (GFAP) and Ubiquitin C-terminal hydrolase (UCH-L1) have been FDA-approved for clinical use in mild and moderate traumatic brain injury (TBI). Understanding sex differences in their diagnostic accuracy over time will help inform clinical practice. We sought to evaluate the sex differences in the temporal profile of GFAP and UCH-L1 in a large cohort of trauma patients presenting to the emergency department. To compare the biomarkers' diagnostic accuracy in male versus female patients for detecting mild TBI (MTBI), and traumatic intracranial lesions on head CT. This prospective cohort study enrolled female and male adult trauma patients presenting to a Level 1 Trauma Center. All patients underwent rigorous screening to determine whether or not they had experienced a MTBI. Of 3025 trauma patients assessed, 1030 met eligibility criteria and 446 declined. Initial blood samples were obtained in 584 patients enrolled within 4 h of injury. Repeated blood sampling was conducted at 4, 8, 12, 16, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180-h post-injury. The main outcomes included the diagnostic accuracy in detection of MTBI and traumatic intracranial lesions on head CT scan. A total of 1831 samples were drawn in 584 patients over 7 days, 362 (62%) were male and 222 (38%) were female. The pattern of elevation was similar in both sexes. Although the pattern of elevation was similar between male and female for both biomarkers, male patients had significantly higher concentrations of UCH-L1 compared to female patients at several timepoints post-injury, particularly within 24 h of injury. There were no significant differences in diagnostic accuracy for detecting MTBI or for detecting CT lesions between male and female patients at any timepoint for both GFAP and UCH-L1. Although patterns of GFAP and UCH-L1 release in trauma patients over a week post-injury was similar between the sexes, there were significantly higher concentrations of UCH-L1 in males at several timepoints post-injury. Despite this, the overall diagnostic accuracies of both GFAP and UCH-L1 over time for detecting MTBI and CT lesions were not significantly different between male and female trauma patients. [ABSTRACT FROM AUTHOR]

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, multi-symptom illness characterized by debilitating fatigue and post-exertional malaise (PEM). Numerous studies have reported sex differences at the epidemiological, cellular, and molecular levels between male and female ME/CFS patients. To gain further insight into these sex-dependent changes, we evaluated differential gene expression by RNA-sequencing (RNA-Seq) in 33 ME/CFS patients (20 female, 13 male) and 34 matched healthy controls (20 female and 14 male) before, during, and after an exercise challenge intended to provoke PEM. Our findings revealed that pathways related to immune-cell signaling (including IL-12) and natural killer cell cytotoxicity were activated as a result of exertion in the male ME/CFS cohort, while female ME/CFS patients did not show significant enough changes in gene expression to meet the criteria for the differential expression. Functional analysis during recovery from an exercise challenge showed that male ME/CFS patients had distinct changes in the regulation of specific cytokine signals (including IL-1β). Meanwhile, female ME/CFS patients had significant alterations in gene networks related to cell stress, response to herpes viruses, and NF-κβ signaling. The functional pathways and differentially expressed genes highlighted in this pilot project provide insight into the sex-specific pathophysiology of ME/CFS. [ABSTRACT FROM AUTHOR]

1. Sex chromosomes of emus are largely homomorphic. Therefore, the standard methodology for molecular sexing based on screening intron length variations in sex-linked genes is not applicable. However, emu sexing requires costly and time-consuming PCR-RFLP or multiplex PCR methods. 2. This experiment used a directed PCR amplification and capillary electrophoresis sexing protocol. Two distinct peaks were observed in females (ZW), while only one peak was observed in males (ZZ). 3. This sexing technique proved to be rapid, non-invasive, and highly sensitive and may be useful for verifying the sex ratio and breeding management of emus. [ABSTRACT FROM AUTHOR]

This review presents information on biochemical features of spermatozoa bearing X or Y chromosome, enabling production of a sperm fraction with pre-defined sex chromosome. The almost only technology currently used for such separation (called sexing) is based on the fluorescence-activated cell sorting of sperm depending on DNA content. In addition to the applied aspects, this technology made it possible to analyze properties of the isolated populations of spermatozoa bearing X or Y chromosome. In recent years, existence of the differences between these populations at the transcriptome and proteome level have been reported in a number of studies. It is noteworthy that these differences are primarily related to the energy metabolism and flagellar structural proteins. New methods of sperm enrichment with X or Y chromosome cells are based on the differences in motility between the spermatozoa with different sex chromosomes. Sperm sexing is a part of the widespread protocol of artificial insemination of cows with cryopreserved semen, it allows to increase proportion of the offspring with the required sex. In addition, advances in the separation of X and Y spermatozoa may allow this approach to be applied in clinical practice to avoid sex-linked diseases. [ABSTRACT FROM AUTHOR]

This study aimed to determine the optimum dosage and duration of diethylstilbestrol hormone (DES) required to produce the highest percentage of females and the use of short sequence repeats (SSRs) markers for the sexing of the Nile tilapia (Oreochromis niloticus). Fries with a total length of 9-11mm were used. DES hormone was added to the fries' feed in two concentrations (100 and 200mg/kg of feed) for 28 and 40 days, excluding the control feed (without DES). To differentiate between normal females (XX) and sex-reversed females (XY), progeny test and SSRs markers were used. The hormonal treatment of 200mg/kg feed for 28 and 40 days gave the highest females percentage, with a slight difference between them (85.51 and 86.54, respectively). While, the treatment for 28 days gave a higher percentage of survival than 40 days (23,00 and 17.33, respectively). From 22 tested females, three XY females were obtained by progeny test and SSRs markers. Production of sex-reversed females can be used as a first step for the production of supper male YY of the Nil tilapia, and SSRs markers can be considered as a promising molecular marker for sex determination that can be used to reduce the duration of the Nile tilapia breeding program. [ABSTRACT FROM AUTHOR]

Immune challenges during gestation are associated with neurodevelopmental disorders and can interact with stress later in life. The pituitary gland participates in endocrine- and immune-related processes that influence development, growth, and reproduction and can modulate physiological and behavioral responses to challenges. The objective of this study was to investigate the effect of stressors at different time points on the molecular mechanisms of the pituitary gland and detect sex differences. RNA sequencing was used to profile the pituitary glands of female and male pigs exposed to weaning stress and virally induced maternal immune activation (MIA), relative to unchallenged groups. Significant effects (FDR-adjusted p-value < 0.05) of MIA and weaning stress were detected in 1829 and 1014 genes, respectively. Of these, 1090 genes presented significant interactions between stressors and sex. The gene ontology biological process of the ensheathment of neurons (GO:0007272), substance abuse, and immuno-related pathways, including the measles disease (ssc05162), encompasses many genes with profiles impacted by MIA and weaning stress. A gene network analysis highlighted the under-expression of myelin protein zero (Mpz) and inhibitors of DNA binding 4 (Id4) among the non-stressed males exposed to MIA, relative to the control and non-MIA males exposed to weaning stress, relative to non-stressed pigs. The detection of changes in the molecular mechanisms of the pituitary gland could advance our understanding of disruptions in the formation of the myelin sheath and the transmission of neuron-to-neuron signals in behavioral disorders associated with maternal immune activation and stress. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explores the use of biometric analysis to identify the sex of Bonelli's eagles, a bird species with reverse sexual dimorphism where females are usually larger than males. By using linear discriminant analysis of biometric variables, we were able to obtain equations that accurately distinguished between male and female eagles, using just two measurements. The study included 137 Bonelli's eagles, 82 nestlings and 55 adults, sampled in eastern Spain from 2015 to 2022. The validation procedure reduced the number of variables used, increasing the accuracy of sexing and saving time. Results showed that the lateral tarsus length and dorso-ventral tarsus length measurements were the most effective in distinguishing between male and female eagles of all age classes, while other variables showed some overlap between sexes. This non-invasive method has multiple applications, including estimation of sex ratio for further studies on population dynamics and extinction risk assessments, which could contribute to the conservation of this endangered species. Biometric analysis allows the sexing of most vertebrates, particularly birds. Birds of prey, and, especially, the Bonelli's eagle (Aquila fasciata), show reverse sexual dimorphism (i.e., females are usually larger than males). In contrast to blood sampling, the use of morphometrics allows sex determination using a non-invasive method, and, therefore, it facilitates fieldwork. By means of a linear discriminant analysis of biometric variables, we obtained different equations that allow the sexing of nestlings and adult Bonelli's eagles. We sampled 137 Bonelli's eagles, 82 nestlings and 55 adults in eastern Spain during the period 2015–2022. The sexes obtained after linear discriminant analysis were compared with their molecular sexing. The validation procedure of the linear discriminant equations facilitated the reduction of the number of variables used and, consequently, optimised working time and sexing accuracy. After validation, some equations showed a 100% sexing efficiency for Bonelli's eagles, particularly for adults. Our results showed that the variables with smaller overlap between the sexes were the lateral tarsus length and dorso-ventral tarsus length, particularly in nestlings. The rest of the variables showed some overlap between the sexes in both age classes. The results we obtained enable the sexing of juvenile and adult Bonelli's eagles in the field using just these two measurements. Hence, this is an easy, accurate, quick and non-invasive method with multiple applications, including in studies on population dynamics, survival analysis or extinction risk assessments, which, ultimately, could contribute to the improvement of the conservation status of this endangered species. [ABSTRACT FROM AUTHOR]

Simple Summary: The gut microbiota forms a complex microecosystem in vertebrates and is affected by various factors. Wild and captive red deer currently live in the same region but have vastly different diets. In this study, the 16S rRNA sequencing technology was performed to evaluate variations in the fecal microbiota of wild and captive individuals of both sexes of red deer. It was found that the composition and function of fecal microbiota in wild and captive environments were significantly different. As a key intrinsic factor, sex has a persistent impact on the formation and development of gut microbiota. Overall, this study reveals differences in the in the fecal microbiota of red deer based on environment and sex. These data could guide future applications of population management in red deer conservation. Gut microbiota play an important role in impacting the host's metabolism, immunity, speciation, and many other functions. How sex and environment affect the structure and function of fecal microbiota in red deer (Cervus elaphus) is still unclear, particularly with regard to the intake of different diets. In this study, non-invasive molecular sexing techniques were used to determine the sex of fecal samples from both wild and captive red deer during the overwintering period. Fecal microbiota composition and diversity analyses were performed using amplicons from the V4–V5 region of the 16S rRNA gene sequenced on the Illumina HiSeq platform. Based on Picrust2 prediction software, potential function distribution information was evaluated by comparing the Kyoto Encyclopedia of Genes and Genome (KEGG). The results showed that the fecal microbiota of the wild deer (WF, n = 10; WM, n = 12) was significantly enriched in Firmicutes and decreased in Bacteroidetes, while the captive deer (CF, n = 8; CM, n = 3) had a significantly higher number of Bacteroidetes. The dominant species of fecal microbiota in the wild and captive red deer were similar at the genus level. The alpha diversity index shows significant difference in fecal microbiota diversity between the males and females in wild deer (p < 0.05). Beta diversity shows significant inter-group differences between wild and captive deer (p < 0.05) but no significant differences between female and male in wild or captive deer. The metabolism was the most important pathway at the first level of KEGG pathway analysis. In the secondary pathway of metabolism, glycan biosynthesis and metabolism, energy metabolism, and the metabolism of other amino acids were significantly different. In summary, these compositional and functional variations in the fecal microbiota of red deer may be helpful for guiding conservation management and policy decision-making, providing important information for future applications of population management and conservation. [ABSTRACT FROM AUTHOR]

Simple Summary: Most bird species have no distinct sexual dimorphic traits. Molecular genetic sexing is considered one of the most accurate methods for sex determination in monomorphic birds. The aim of this study was to compare the sexing results obtained by PCR method from paired samples of feathers and oral swabs collected from the same individuals. Oral swabs proved to be a more reliable sample for genetic sex determination in the species tested in this study, especially for featherless, newly hatched chicks. The early age determinism of the sex in case of monomorphic birds is very important, because most companion birds have no distinct sexual dimorphic traits. Molecular genetic sexing was proved to be one of the most accurate sex determinations in monomorphic birds. The aim of this study was to compare the results obtained by PCR performed on isolate genomic DNA from paired samples of feathers and oral swabs collected from the same individuals. Samples of oral swabs (n = 101) and feathers (n = 74) were collected from 101 companion birds from four different species (Columba livia domestica, Psittacula krameri, Neophema splendida and Agapornis spp.). The PCR was performed for the amplification of the CHD1W and CHD1Z genes in females and the CHD1Z gene in males. The overall PCR success rate of sex determination was significantly higher from oral swabs than from feathers. The PCR success rate from oral swabs was higher in juveniles and from feathers was significantly higher in adults. The similarity between the oral swab and feathers was obtained in 78.38% of the birds. Oral swabs proved to be a more reliable sample for genetic sex determination in the species tested in this study. [ABSTRACT FROM AUTHOR]

Incorporating sex ratios of nestlings into population viability studies increases knowledge of overall health of endangered populations. Currently, a reliable non-invasive method to identify the sex of golden eagle nestlings is not available; however, claims are commonly made based on morphology. Ten biometric measurements from 43 Scottish golden eagles aged 2–7.5 weeks were assessed to see if sex could actually be determined using this non-invasive methodology. Sex was confirmed via molecular analysis of blood samples. Discrete and principal component analyses of the different biometrics could not correctly determine individual nestling sex. Therefore, despite being more invasive, molecular sexing remains the recommended tool of choice for accurate sex identification of Scottish golden eagle nestlings younger than 7.5 weeks of age. This has important implications for golden eagle field studies where empirical morphological measurements are frequently and typically taken, but we have shown are not reliable in determining the sex of such young nestlings. [ABSTRACT FROM AUTHOR]

Differentiated sex chromosomes are believed to be evolutionarily stable, while poorly differentiated sex chromosomes are considered to be prone to turnovers. With around 1700 currently known species forming ca 15% of reptile species diversity, skinks (family Scincidae) are a very diverse group of squamates known for their large ecological and morphological variability. Skinks generally have poorly differentiated and cytogenetically indistinguishable sex chromosomes, and their sex determination was suggested to be highly variable. Here, we determined X-linked genes in the common sandfish (Scincus scincus) and demonstrate that skinks have shared the same homologous XX/XY sex chromosomes across their wide phylogenetic spectrum for at least 85 million years, approaching the age of the highly differentiated ZZ/ZW sex chromosomes of birds and advanced snakes. Skinks thus demonstrate that even poorly differentiated sex chromosomes can be evolutionarily stable. The conservation of sex chromosomes across skinks allows us to introduce the first molecular sexing method widely applicable in this group. [ABSTRACT FROM AUTHOR]

More than a half of bird species around the world are monomorphic, therefore they do not show distinct sexual dimorphic traits. The paper aims to present three molecular methods for sex identification of monomorphic companion birds. Samples of feathers, oral swabs and blood were collected from Psittaciformes (Ara ararauna, Psittacus erithacus and Psittacula krameri) and Columbiformes (Columba livia domestica). All samples were tested by three different PCR protocols in order to identify the chromo-helicase-DNA-binding (CHD1)-W gene and CHD1-Z genes in females and the CHD1-Z gene in males. Two protocols were conventional PCR, using P2 and P8, respectively P2 and NP primers, while the third protocol was a multiplex PCR using P0, P2 and P8 primers. As a conclusion, all three PCR protocols can be used for molecular sexing of monomorphic Psittaciformes and Columbiformes companion birds. Feather, oral swab and blood samples provided adequate DNA templates for the sex identification of birds. [ABSTRACT FROM AUTHOR]

The forces which shape avian species' vocalization and coloration continue to draw scientific attention. The White-throated Kingfisher, (Halcyon smyrnensis), is a non-passerine, resident, generalist predator characterized by elaborate colors and vocalizations and is highly abundant throughout its species range. However, despite these characteristics this species has been relatively unstudied. Here we studied the White-throated Kingfisher population in the Hula Valley, Israel, a population residing at the western edge of this species' range. Using individual marking, nest surveys, acoustic recordings, digital photography, spectrometry and molecular sexing we describe this resident species' breeding ecology, morphology and vocal repertoire. We further examine whether these traits are sexually dimorphic and whether they correlate with measures of reproductive success (clutch size). We show that the breeding ecology (e.g. incubation time) differs from some of the reported studies. We further demonstrate, for the first time, that this non-passerine species has a vocal repertoire of at least 13 distinct vocalizations; both males and females seem to produce the majority of these vocalizations. A specific vocalization (long trill) is sexually dimorphic, and the rate of the trill correlates with male reproductive success. The elaborate coloration also shows significant sexual dimorphism: males have brighter blueish dorsal feathers and darker saturated brown ventral feathers. Taken together, specifically with this species being non-passerine, the unique ecology of this western population and the various traits which show sexual dimorphism define this resident species as a unique abundant model species for examining various ecological and evolutionary processes. [ABSTRACT FROM AUTHOR]

Sperm sexing is a technique for spermatozoa sorting into populations enriched with X- or Y-chromosome-bearing cells and is widely used in the dairy industry. Investigation of the characteristics of sorted semen is of practical interest, because it could contribute to the enhancement of sexed semen fertility characteristics, which are currently lower than those of conventional semen. Comparison of a spermatozoa population enriched with X-chromosome-bearing cells to a mixed population is also intriguing in the context of potential differences that drive the mechanisms of primary sex-ratio determination. In this work, sexed (X spermatozoa) and conventional spermatozoa of Holstein bulls were analyzed for the content and enzymatic activity of GAPDHS, a sperm-specific isoform of glyceraldehyde-3-phosphate dehydrogenase that plays a significant role in the regulation of flagellar activity. No difference in the amount of this glycolysis enzyme per cell was revealed, but, notably, GAPDHS enzymatic activity in the sexed samples was significantly higher. Enzymatic activity among the group of sexed but not conventional sperm samples positively correlated with spermatozoa motility, which indicates the significant role of this enzyme for the sorted cells population. [ABSTRACT FROM AUTHOR]