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Drosophila prolongata is a member of the melanogaster species group and rhopaloa subgroup native to the subtropical highlands of southeast Asia. This species exhibits an array of recently evolved male-specific morphological, physiological, and behavioral traits that distinguish it from its closest relatives, making it an attractive model for studying the evolution of sexual dimorphism and testing theories of sexual selection. The lack of genomic resources has impeded the dissection of the molecular basis of sex-specific development and behavior in this species. To address this, we assembled the genome of D. prolongata using long-read sequencing and Hi-C scaffolding, resulting in a highly complete and contiguous (scaffold N50 2.2Mb) genome assembly of 220Mb. The repetitive content of the genome is 24.6%, the plurality of which are LTR retrotransposons (33.2%). Annotations based on RNA-seq data and homology to related species revealed a total of 19,330 genes, of which 16,170 are protein-coding. The assembly includes 98.5% of Diptera BUSCO genes, including 93.8% present as a single copy. Despite some likely regional duplications, the completeness of this genome suggests that it can be readily used for gene expression, GWAS, and other genomic analyses.

Houseflies (Musca domestica) (Diptera: Muscidae) are medically important insect species because they serve as vectors of pathogens. The study generally described the sexual dimorphism of M. domestica based on their wing size and wing shape. This study examined 25 males and 25 females of F1 offspring from wild-caught M. domestica parents. The wings were digitized and 17 landmarks were obtained, scaled, translated, and rotated in General Procrustes Analysis. The wing size (centroid size) of male M. domestica species was significantly larger compared to females (t = - 2.38, df = 48, p = 0.0200). Principal Component Analysis (PCA) and Relative Warp Analysis (RWA) revealed that 29.72% of shape variation from the original data was attributed to a narrow wing shape, and 14.60% toa broad wing shape. Discriminant Function Analysis (DFA) successfully distinguished female and male species based on wing shape, in which males have narrower wings compared to females, indicating the occurrence of sexual dimorphism in wings. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to conduct a thorough characterization of hand morphology. Employing a 2D geometric morphometric approach, we scrutinize individual fingers and the palm, delineating the ontogenetic trajectories for each biological sex and investigating the alterations that take place at various stages of human development. Materials and methods: A set of thirty‐two 2D anatomical landmarks were assessed in a sex‐balanced sample of human hands (F = 275, M = 250 males), spanning all stages of human development. Following Procrustes registration, the data on size and shape for individual fingers and the palm were examined for each biological sex and age group. Regression analysis was utilized to quantify ontogenetic trajectories for each biological sex. Results: The findings suggest a gradual escalation in sexual dimorphism throughout human development, with statistically noteworthy distinctions becoming apparent in size starting at the age of 3, and in shape from the age of 7 onwards. Additionally, our analyses uncover a distinctive sigmoid pattern between sexes, indicating that biological male hands exhibit a sturdier build compared to biological female hands from early childhood onward. Conclusions: In conclusion, this study enriches our insights into sexual dimorphism in human hands, stressing the importance of considering both size and shape across different ontogenetic stages. These findings not only expand our understanding of human biological variation but also lay the foundation for future interdisciplinary research in diverse scientific domains. [ABSTRACT FROM AUTHOR]

Scapula shape is highly variable across humans and appears to be sexually dimorphic—differing significantly between biological males and females. However, previous investigations of sexual dimorphism in scapula shape have not considered the effects of allometry (the relationship between size and shape). Disentangling allometry from sexual dimorphism is necessary because apparent sex‐based differences in shape could be due to inherent differences in body size. This study aimed to investigate sexual dimorphism in scapula shape and examine the role of allometry in sex‐based variation. We used three‐dimensional geometric morphometrics with Procrustes ANOVA to quantify scapula shape variation associated with sex and size in 125 scapulae. Scapula shape significantly differed between males and females, and males tended to have larger scapulae than females for the same body height. We found that males and females exhibited distinct allometric relationships, and sexually dimorphic shape changes did not align with male‐ or female‐specific allometry. A secondary test revealed that sexual dimorphism in scapula shape persisted between males and females of similar body heights. Overall, our findings indicate that there are sex‐based differences in scapula shape that cannot be attributed to size‐shape relationships. Our results shed light on the potential role of sexual selection in human shoulder evolution, present new hypotheses for biomechanical differences in shoulder function between sexes, and identify relevant traits for improving sex classification accuracy in forensic analyses. [ABSTRACT FROM AUTHOR]

Sexual dimorphism in prevalence, severity and genetic susceptibility exists for most common diseases. However, most genetic and clinical outcome studies are designed in sex-combined framework considering sex as a covariate. Few sex-specific studies have analyzed males and females separately, which failed to identify gene-by-sex interaction. Here, we propose a novel unified biologically interpretable deep learning-based framework (named SPIN) for sexual dimorphism analysis. We demonstrate that SPIN significantly improved the C-index up to 23.6% in TCGA cancer datasets, and it was further validated using asthma datasets. In addition, SPIN identifies sex-specific and -shared risk loci that are often missed in previous sex-combined/-separate analysis. We also show that SPIN is interpretable for explaining how biological pathways contribute to sexual dimorphism and improve risk prediction in an individual level, which can result in the development of precision medicine tailored to a specific individual's characteristics. [ABSTRACT FROM AUTHOR]

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects men more than women, with severity increasing post menopause, indicating sex-based disparities in MASLD prevalence and progression. Estrogen protects women from MASLD, while the effects of testosterone vary among men and women. This indicates that different sex-dimorphic mechanisms are involved in sex-hormone signaling. Innate immune cells display significant sexual dimorphism in their response to MASLD, wherein male immune cells evidence a more migratory and proinflammatory phenotype. Sex-specific genetic variants and gut microbiota influence MASLD risk, highlighting the opportunity for developing personalized treatments based on individual genetic or microbiome profiles. Current preclinical MASLD models are male biased, indicating the challenges in translating research findings into clinical therapies for developing gender-specific MASLD treatment. Growing evidence suggests that metabolic dysfunction-associated steatotic liver disease (MASLD) is significantly higher in men versus women. Increased prevalence is observed in postmenopausal women, suggesting that age and sex (hormones) influence MASLD development and progression. Molecular data further reveal that sex regulates the innate immune responses with an essential role in MASLD progression. To date, there has been limited focus on the role of innate immune sexual dimorphism in MASLD, and differences between men and women are not considered in the current drug discovery landscape. In this review, we summarize the sex disparities and innate immune sexual dimorphism in MASLD pathogenesis. We further highlight the importance of harnessing sexual dimorphism in identifying therapeutic targets, developing pharmacological therapies, and designing (pre-) clinical studies for the personalized treatment for MASLD. [ABSTRACT FROM AUTHOR]

Subcutaneous white adipose tissue (scWAT) is a dynamic storage and secretory organ that regulates systemic homeostasis, yet the impact of endurance exercise training (ExT) and sex on its molecular landscape is not fully established. Utilizing an integrative multi-omics approach, and leveraging data generated by the Molecular Transducers of Physical Activity Consortium (MoTrPAC), we show profound sexual dimorphism in the scWAT of sedentary rats and in the dynamic response of this tissue to ExT. Specifically, the scWAT of sedentary females displays -omic signatures related to insulin signaling and adipogenesis, whereas the scWAT of sedentary males is enriched in terms related to aerobic metabolism. These sex-specific -omic signatures are preserved or amplified with ExT. Integration of multi-omic analyses with phenotypic measures identifies molecular hubs predicted to drive sexually distinct responses to training. Overall, this study underscores the powerful impact of sex on adipose tissue biology and provides a rich resource to investigate the scWAT response to ExT.

Cranial sexual dimorphism in grey wolf (Canis lupus Linnaeus, 1758) from Bulgaria has not been studied so far. Skulls from adult individuals from across the country were studied. Thirty-six parameters (35 craniodental measurements and a volumetric one) of each skull were measured. The Bulgarian wolf population exhibits weak craniodental sexual dimorphism, which is male-biased, as is typical in canids with a monogamous social system. However, the sexual dimorphism is more pronounced than in the studied more northern populations.

Plumage pigmentation and ornamentation can indicate male phenotypic quality in many avian species and represent traits that are often selected for by females. Melanins are some of the most widespread classes of pigments in the animal kingdom and form the many shades of black and brown feather colors across raptor taxa. Eumelanin is responsible for the darker shades of black and brown, whereas pheomelanin is responsible for the lighter brown shades and rusty red coloration that are found in many buteonine raptors, including Swainson's Hawks (Buteo swainsoni). Plumage polymorphism has been examined in various raptor species along with morphometric differences as a basis for sexual dimorphism; however, the potential for sexual dimorphism in the form of pheomelanin-pigmented plumage has rarely been discussed. We examined this phenomenon in Swainson's Hawks by digitally sampling breast feathers from adult museum specimens, and we utilized an imaging toolbox for multispectral image analysis in the open-source ImageJ software to compare red pixel values between sexes. We found a significant difference in normalized red pixel value means between male and female birds, with higher redness values strongly correlating with male individuals, regardless of morph type. This indicates a relationship between pheomelanin pigmentation and sex, illustrating a basis for sexual dimorphism within the species, as well as the potential for sexual selection of redder males. [ABSTRACT FROM AUTHOR]

Chiroptera is the only mammalian order that has adapted to active flight, offering a unique platform to study ecomorphological adaptations. While bats exhibit a diverse diet, the focus of this study is on insectivorous bats, specifically four species: Myotis daubentonii, Nyctalus noctula, Plecotus austriacus and Rhinolophus ferrumequinum. It is important to note that despite sharing an insectivorous diet, these species occupy different ecological niches, perform distinct feeding strategies and explore varied habitats to capture prey. Using 2‐D geometric morphometrics, we analysed a sample of mandibles to identify differences in size and shape among these species. We also investigated ecogeographical variation within their overlapping distribution across continental Europe. Significant differences in both mandibular size and shape were found among the four species. Sexual dimorphism influenced only the mandibular shape of R. ferrumequinum. A latitudinal gradient in mandibular size was found solely in N. noctula, while longitude significantly explained shape variation in M. daubentonii. These findings suggest that even within the ecological guild of insectivorous bats, there exists a diverse range of morphological adaptations that allow these species to occupy distinct ecological niches. [ABSTRACT FROM AUTHOR]

Sexual dimorphism arises because of divergent fitness optima between the sexes. Phenotypic divergence between sexes can range from mild to extreme. Fireflies, bioluminescent beetles, present various degrees of sexual dimorphism, with species showing very mild sexual dimorphism to species presenting female-specific neoteny, posing a unique framework to investigate the evolution of sexually dimorphic traits across species. In this work, we present novel assembled genomes of two firefly species, Lamprohiza splendidula and Luciola italica, species with different degrees of sexual dimorphism. We uncover high synteny conservation of the X-chromosome across ~ 180 Mya and find full X-chromosome dosage compensation in our two fireflies, hinting at common mechanism upregulating the single male X-chromosome. Different degrees of sex-biased expressed genes were found across two body parts showing different proportions of expression conservation between species. Interestingly, we do not find X-chromosome enrichment of sex-biased genes, but retrieve autosomal enrichment of sex-biased genes. We further uncover higher nucleotide diversity in the intronic regions of sex-biased genes, hinting at a maintenance of heterozygosity through sexual selection. We identify different levels of sex-biased gene expression divergence including a set of genes showing conserved sex-biased gene expression between species. Divergent and conserved sex-biased genes are good candidates to test their role in the maintenance of sexually dimorphic traits. Sexual dimorphism reflects divergent requirements between the sexes. We explore gene expression between two fireflies that show mild and extreme dimorphism. We uncover conserved and divergent gene expression, including complete dosage compensation. [ABSTRACT FROM AUTHOR]

Sexual dimorphism affects various biological functions, including immune responses. However, the mechanisms by which sex alters immunity remain largely unknown. Using Caenorhabditis elegans as a model species, we showed that males exhibit enhanced immunity against various pathogenic bacteria through the upregulation of HLH-30 (Helix Loop Helix 30/TFEB (transcription factor EB)), a transcription factor crucial for macroautophagy/autophagy. Compared with hermaphroditic C. elegans, males displayed increased activity of HLH-30/TFEB, which contributed to enhanced antibacterial immunity. atg-2 (AuTophaGy (yeast Atg homolog) 2) upregulated by HLH-30/TFEB mediated increased immunity in male C. elegans. Thus, the males appear to be equipped with enhanced HLH-30/TFEB-mediated autophagy, which increases pathogen resistance, and this may functionally prolong mate-searching ability with reduced risk of infection.Abbreviations: atg-2: AuTophaGy (yeast Atg homolog) 2; FUDR: 5-fluoro-2’-deoxyuridine; GSEA: gene set enrichment analysis; HLH-30: Helix Loop Helix 30; LC3: microtubule associated protein 1 light chain 3; NGM: nematode growth media; RNA-seq: RNA sequencing; SEM: standard error of the mean; TFEB: transcription factor EB; WT: wild-type [ABSTRACT FROM AUTHOR]

Abstract Introduction Sexual dimorphism significantly influences cancer incidence and prognosis. Notably, females exhibit a lower risk and favorable prognosis for non-reproductive cancers compared to males, a pattern observable beyond the scope of risk behaviors such as alcohol consumption and smoking. Colorectal cancer, ranking third in global prevalence and second in mortality, disproportionately affects men. Sex steroid hormones, particularly estrogens and androgens, play crucial roles in cancer progression, considering epidemiological in vivo and in vitro, in general estrogens imparting a protective effect in females and androgens correlating with an increasing risk of colorectal cancer development. Main body The hormonal impact on immune response is mediated by receptor interactions, resulting in heightened inflammation, modulation of NF-kB, and fostering an environment conducive to cancer progression and metastasis. These molecules also influence the enteric nervous system, that is a pivotal in neuromodulator release and intestinal neuron stimulation, also contributes to cancer development, as evidenced by nerve infiltration into tumors. Microbiota diversity further intersects with immune, hormonal, and neural mechanisms, influencing colorectal cancer dynamics. A comprehensive understanding of hormonal influences on colorectal cancer progression, coupled with the complex interplay between immune responses, microbiota diversity and neurotransmitter imbalances, underpins the development of more targeted and effective therapies. Conclusions Estrogens mitigate colorectal cancer risk by modulating anti-tumor immune responses, enhancing microbial diversity, and curbing the pro-tumor actions of the sympathetic and enteric nervous systems. Conversely, androgens escalate tumor growth by dampening anti-tumor immune activity, reducing microbial diversity, and facilitating the release of tumor-promoting factors by the nervous system. These findings hold significant potential for the strategic purposing of drugs to fine-tune the extensive impacts of sex hormones within the tumor microenvironment, promising advancements in colorectal cancer therapies.

Abstract Background In day-old Hungarian white goose goslings, there is a noticeable difference in dorsal down coloration between males and females, with females having darker dorsal plumage and males having lighter plumage. The ability to autosex day-old goslings based on their dorsal down coloration is important for managing them efficiently and planning their nutrition in the poultry industry. The aim of this study was to determine the biological and genetic factors underlying this difference in dorsal down colorationthrough histological analysis, biochemical assays, transcriptomic profiling, and q‒PCR analysis. Results Tissue analysis and biochemical assays revealed that compared with males, 17-day-old embryos and day-old goslings of female geese exhibited a greater density of melanin-containing feather follicles and a greater melanin concentration in these follicles during development. Both female and male goslings had lower melanin concentrations in their dorsal skin compared to 17-day-old embryos. Transcriptome analysis identified a set of differentially expressed genes (DEGs) (MC1R, TYR, TYRP1, DCT and MITF) associated with melanogenesis pathways that were downregulated or silenced specifically in the dorsal skin of day-old goslings compared to 17-day-old embryos, affecting melanin synthesis in feather follicles. Additionally, two key genes (MC1R and MITF) associated with feather coloration showed differences between males and females, with females having higher expression levels correlated with increased melanin synthesis and darker plumage. Conclusion The expression of multiple melanogenesis genes determines melanin synthesis in goose feather follicles. The dorsal down coloration of day-old Hungarian white goose goslings shows sexual dimorphism, likely due to differences in the expression of the MC1R and MITF genes between males and females. These results could help us better understand why male and female goslings exhibit different plumage patterns.

Background: Dermatoglyphics is the study of epidermal ridge patterns on the fingers, palms, and soles. Correlation of dermatoglyphic patterns with many chromosomal abnormalities and genetic predisposing diseases such as diabetes mellitus, hypertension, schizophrenia, and bronchial asthma is evidenced by many researchers. Literature on sexual dimorphism of dermatoglyphic patterns revealed it as an important characteristic feature. Aims and Objectives: The aim of the study is to study the variance of ridge patterns among male and female patients of Type 2 diabetes mellitus patients of West Bengal and determine the sex-specific digital and palmar ridge patterns in Type 2 Diabetes mellitus. Materials and Methods: A cross-sectional study has been done on 100 male and 100 female Type 2 diabetes mellitus patients. Digital and palmar prints were taken by the traditional ink method. Digital ridge pattern, pattern intensity index, total finger ridge count (TFRC), absolute finger ridge count (AFRC), and a-b ridge count were studied. The data on these patterns was recorded and statistically analyzed by Chi-square test and Student’s t-test. Results: The frequency of ulnar loop is higher in female diabetics in comparison to male diabetics. Statistically significant increase in mean TFRC and mean AFRC is seen in male diabetics. Conclusion: Our study exhibits that dermatoglyphic pattern significantly differs in male and female diabetics. The knowledge and reference range of dermatoglyphic parameters among male and female diabetics are essential in the use of this study as a screening tool or diagnostic tool in Type 2 diabetes mellitus.

Objective: This study aims to evaluate the sexual dimorphism of maxillary sinuses (MS) using cone-beam computed tomography (CBCT). Method: A total of 80 CBCT scans were taken from Peruvian patients aged between 20 and 70 years-old. The dimensions (length, width, and height) of the MS were measured and evaluated. The data were analyzed using the Mann-Whitney U test with a significance level of p

Based on several earwigfly specimens with well‐preserved mouthparts of Meropeidae from mid‐Cretaceous Burmese amber, a detailed, initial analysis was conducted of the structure of Mesozoic meropeids. Compared to the singularly flattened mandible of modern meropeids, the new specimens reveal that Mesozoic representatives had two distinct types of mandibles: blade‐shaped and scoop‐shaped. Current fossil evidence indicates that during the Mesozoic Era, Meropeidae displayed sexual dimorphism that was reflected in the structure of their mandibles. This structural difference may indicate that about 99 million years ago, meropeids had a more complex diet than extant confamilial taxa. Phylogenetic results suggest that Torvimerope gen. nov., along with Burmomerope, two extinct genera, form a clade and that are the sister taxon to crown‐group Meropeidae. The new material offers new possibilities for inferring the feeding habits and mating behavior of early Meropeidae. [ABSTRACT FROM AUTHOR]

This paper presents information on the morphological, morphometric, and dental sex differences in the dwarf round ray Urotrygon nana. We recorded 12 morphological traits, sex, the distribution pattern of dermal denticles, the number of tooth rows, and the tooth shape of 466 individuals. The disc width of females ranged from 50 to 172 mm and that of males ranged from 53 to 135 mm. A neuronal classification model and a correspondence analysis showed that female disc width was 21.5% broader, and the distance from the rostrum to the anus was 17.7% longer than that of males, whereas males presented 19.5% greater distance between the nostrils, 9.7% greater preorbital snout length, 6.8% greater cloaca to caudal‐fin length, 2.7% greater interorbital distance, and 1.1% greater total length than females. The disc of adult males, including the abdominal cavity area, was densely covered with dermal denticles, which were slightly larger than those observed in females. Females presented homodont dentition with molariform teeth and a smooth lozenge‐shaped crown with rounded margins. Males exhibited homodonty but with tooth morphology variations in individuals of different sizes (from molariforms to sharper cusp teeth). There were changes in disc shape (from subcircular to oval), distribution and size of dermal denticles (more abundant and larger), and tooth shape (from molariform to monocuspid teeth) during male development, from neonates to adults. U. nana exhibited sexual dimorphism in size, disc shape, number and shape of teeth, and distribution and size of dermal denticles. [ABSTRACT FROM AUTHOR]

Background: Dermatoglyphics is the study of epidermal ridge patterns on the fingers, palms, and soles. Correlation of dermatoglyphic patterns with many chromosomal abnormalities and genetic predisposing diseases such as diabetes mellitus, hypertension, schizophrenia, and bronchial asthma is evidenced by many researchers. Literature on sexual dimorphism of dermatoglyphic patterns revealed it as an important characteristic feature. Aims and Objectives: The aim of the study is to study the variance of ridge patterns among male and female patients of Type 2 diabetes mellitus patients of West Bengal and determine the sex-specific digital and palmar ridge patterns in Type 2 Diabetes mellitus. Materials and Methods: A cross-sectional study has been done on 100 male and 100 female Type 2 diabetes mellitus patients. Digital and palmar prints were taken by the traditional ink method. Digital ridge pattern, pattern intensity index, total finger ridge count (TFRC), absolute finger ridge count (AFRC), and a-b ridge count were studied. The data on these patterns was recorded and statistically analyzed by Chi-square test and Student's t-test. Results: The frequency of ulnar loop is higher in female diabetics in comparison to male diabetics. Statistically significant increase in mean TFRC and mean AFRC is seen in male diabetics. Conclusion: Our study exhibits that dermatoglyphic pattern significantly differs in male and female diabetics. The knowledge and reference range of dermatoglyphic parameters among male and female diabetics are essential in the use of this study as a screening tool or diagnostic tool in Type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

Objective: Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality, and its incidence is increasing due to endemic obesity. HCC is sexually dimorphic in both humans and rodents with higher incidence in males, although the mechanisms contributing to these correlations remain unclear. Here, we examined the role of sphingosine kinase 2 (SphK2), the enzyme that regulates the balance of bioactive sphingolipid metabolites, sphingosine-1-phosphate (S1P) and ceramide, in gender specific MASH-driven HCC. Methods: Male and female mice were fed a high fat diet with sugar water, a clinically relevant model that recapitulates MASH-driven HCC in humans followed by physiological, biochemical cellular and molecular analyses. In addition, correlations with increased risk of HCC recurrence were determined in patients. Results: Here, we report that deletion of SphK2 protects both male and female mice from Western diet-induced weight gain and metabolic dysfunction without affecting hepatic lipid accumulation or fibrosis. However, SphK2 deficiency decreases chronic diet-induced hepatocyte proliferation in males but increases it in females. Remarkably, SphK2 deficiency reverses the sexual dimorphism of HCC, as SphK2−/− male mice are protected whereas the females develop liver cancer. Only in male mice, chronic western diet induced accumulation of the autophagy receptor p62 and its downstream mediators, the antioxidant response target NQO1, and the oncogene c-Myc. SphK2 deletion repressed these known drivers of HCC development. Moreover, high p62 expression correlates with poor survival in male HCC patients but not in females. In hepatocytes, lipotoxicity-induced p62 accumulation is regulated by sex hormones and prevented by SphK2 deletion. Importantly, high SphK2 expression in male but not female HCC patients is associated with a more aggressive HCC differentiation status and increased risk of cancer recurrence. Conclusions: This work identifies SphK2 as a potential regulator of HCC sexual dimorphism and suggests SphK2 inhibitors now in clinical trials could have opposing, gender-specific effects in patients.

Individual identification is a critical focus of forensic research, aiming to achieve heightened accuracy in the identification process. Particularly in cases involving fragmented and damaged skeletal remains, sex determination plays a pivotal role. It is imperative to establish the precision of cadaver bones in such scenarios. This research aimed to evaluate sex-based differences and assess age using bimastoid width measured through digital computed tomography images. The study included a total of 153 adults (77 males and 76 females) aged between 15 and 50. Bimastoid breadth measurements were obtained from CT scan images of the skull base, revealing that bimastoid distance is larger in males compared to females. The study observed significant differences in bimastoid breadth between men and women, with an average mastoid width of 132.371 in men and 121.724 in women. The findings indicate that the measurement of bimastoid breadth does not significantly change with increasing age. However, substantial differences were found between men and women in bimastoid breadth measurements, which can be utilized to determine sex in forensic investigations.

IntroductionJapanese quail are of significant economic value, providing protein nutrition to humans through their reproductive activity; however, sexual dimorphism in this species remains relatively unexplored compared with other model species.MethodA total of 114 RNA sequencing datasets (18 and 96 samples for quail and chicken, respectively) were collected from existing studies to gain a comprehensive understanding of sexual dimorphism in quail. Cross-species integrated analyses were performed with transcriptome data from evolutionarily close chickens to identify sex-biased genes in the embryonic, adult brain, and gonadal tissues.ResultsOur findings indicate that the expression patterns of genes involved in sex-determination mechanisms during embryonic development, as well as those of most sex-biased genes in the adult brain and gonads, are identical between quails and chickens. Similar to most birds with a ZW sex determination system, quails lacked global dosage compensation for the Z chromosome, resulting in directional outcomes that supported the hypothesis that sex is determined by the individual dosage of Z-chromosomal genes, including long non-coding RNAs located in the male hypermethylated region. Furthermore, genes, such as WNT4 and VIP, reversed their sex-biased patterns at different points in embryonic development and/or in different adult tissues, suggesting a potential hurdle in breeding and transgenic experiments involving avian sex-related traits.DiscussionThe findings of this study are expected to enhance our understanding of sexual dimorphism in birds and subsequently facilitate insights into the field of breeding and transgenesis of sex-related traits that economically benefit humans.

BackgroundThe gut microbiome plays a key role in the formation of livestock and poultry traits via serum metabolites, and empirical evidence has indicated these traits are sex-linked.MethodsWe examined 106 chickens (54 male chickens and 52 female chickens) and analyzed cecal content samples and serum samples by 16S rRNA gene sequencing and non-targeted metabolomics, respectively.ResultsThe cecal microbiome of female chickens was more stable and more complex than that of the male chickens. Lactobacillus and Family XIII UCG-001 were enriched in male chickens, while Eubacterium_nodatum_group, Blautia, unclassified_Anaerovoraceae, Romboutsia, Lachnoclostridium, and norank_Muribaculaceae were enriched in female chickens. Thirty-seven differential metabolites were identified in positive mode and 13 in negative mode, showing sex differences. Sphingomyelin metabolites possessed the strongest association with cecal microbes, while 11β-hydroxytestosterone showed a negative correlation with Blautia.ConclusionThese results support the role of sexual dimorphism of the cecal microbiome and metabolome and implicate specific gender factors associated with production performance in chickens.

Obesity incidence is increasing worldwide with the urgent need to identify new therapeutics. Sex differences in immune cell activation drive obesity-mediated pathologies where males are more susceptible to obesity comorbidities and exacerbated inflammation. Here, we demonstrate that the macrophage-secreted protein RELMα critically protects females against high-fat diet (HFD)-induced obesity. Compared to male mice, serum RELMα levels were higher in both control and HFD-fed females and correlated with frequency of adipose macrophages and eosinophils. RELMα-deficient females gained more weight and had proinflammatory macrophage accumulation and eosinophil loss in the adipose stromal vascular fraction (SVF), while RELMα treatment or eosinophil transfer rescued this phenotype. Single-cell RNA-sequencing of the adipose SVF was performed and identified sex and RELMα-dependent changes. Genes involved in oxygen sensing and iron homeostasis, including hemoglobin and lncRNA Gm47283/Gm21887, correlated with increased obesity, while eosinophil chemotaxis and response to amyloid-beta were protective. Monocyte-to-macrophage transition was also dysregulated in RELMα-deficient animals. Collectively, these studies implicate a RELMα-macrophage-eosinophil axis in sex-specific protection against obesity and uncover new therapeutic targets for obesity.

Macrobrachium jelskii is an endemic shrimp species of South America, with a wide geographical distribution. Although there have been some studies on this organism, information regarding the relative growth of body structures has never been fully explored. In this regard, we aim to analyse the relative growth of this species, in order to investigate the developmental pattern between juveniles and adults, as well as to estimate the morphological sexual maturity (MSM). For morphometric analysis and MSM estimation, the following structures were measured: carapace length (CL); abdomen length (AL); propodus (CPL) and dactyl length (DL) of the second pair of pereopods; second pleonal pleuron width (SPW); and appendix masculina length (AML). We observed developmental differences between juveniles and adults, especially in males. The MSM size for males was estimated at 7.47 mm CL, while for females it was 8.77 mm CL. Females exhibit significantly larger sizes compared to males. Our study reveals divergent energy allocation between juvenile and adult M. jelskii, with males and females reaching MSM at different sizes. The development of these structures with varying allometric constants throughout life stages suggests a strong connection to reproductive behaviour, meeting the specific needs of each life stage’s behavioural repertoire. [ABSTRACT FROM AUTHOR]

IntroductionIn colorectal cancer, men exhibit a higher incidence than women, and there is a disturbance in the levels of sex steroids in serum in patients with this disease. Consistently, in animals, males have greater tumor growth than females in diverse models. Nevertheless, the role of sex steroids is not well established. For that, we analyzed the effect of the principal gonadal sex steroids in both sexes. We determined sex as a statistically risk factor for colorectal cancer with data obtained from GLOBOCAN database.MethodsTo induce colorectal tumors, we used the gold standard chemical method of azoxymethane and dextran sulphate of sodium. To evaluate the role of sex steroids, we gonadectomized independent males and female animals, reconstituting and substituting them with 17β estradiol and dihydrotestosterone. Finally, we determined, in vitro, the proliferation of a human cell line exposed to 17β estradiol, testosterone, or dihydrotestosterone. Sex, as a risk factor for colorectal cancer, showed a statistically significant susceptibility of men over 50 years old.ResultsIn vivo, males develop a greater number of tumors and with a larger size than females. In males, orchiectomy prevents tumor growth, whereas in females, ovariectomy promotes the development of neoplasms. DHT acts as a protumoral agent in both sexes. 17β estradiol reduces tumor growth in females but enhances it in males, showing a dimorphic effect. In vitro studies reveal that estradiol decreases the proliferation of the HCT-116 colon cancer cell line, while testosterone boosts proliferation in these cells. Interestingly, dihydrotestosterone does not influence proliferation.

The existence of adult sexual dimorphism is typically explained as a consequence of sexual selection, yet coevolutionary drivers of sexual dimorphism frequently remain untested. Here, I investigate the role of sexual dimorphism in host–parasite interactions of the brood parasitic diederik cuckoo, Chrysococcyx caprius. Female diederik cuckoos are more cryptic in appearance and pose a threat to the clutch, while male diederik cuckoos are conspicuous and not a direct threat. Specifically, I examine whether sexual dimorphism in diederik cuckoos provokes threat‐level sensitive responses in Southern red bishop, Euplectes orix, hosts. I use experimentally simulated nest intrusions to test whether hosts have the capacity to differentially (i) detect, and/or (ii) discriminate between, male and female diederik cuckoos, relative to harmless controls. Overall, I found no evidence that diederik cuckoos differ in detectability, since both sexes are comparable to controls in the probability and speed of host detection. Furthermore, neither male nor female hosts discriminate between sexually dimorphic diederik cuckoos when engaging in frontline nest defences. However, hosts that witnessed a male diederik cuckoo during the trial were more likely to reject odd eggs. Moreover, experimental eggs were significantly more likely to be rejected when female bishops observed a male compared to a female diederik cuckoo. While the cryptic appearance of female diederik cuckoos does not reduce detection by hosts, it does provide the benefit of anonymity given the egg rejection costs of conspicuous male‐like appearance in the nest vicinity. These findings have implications for the evolution and maintenance of sexual dimorphism across the Cuculidae, and highlight the value of testing assumptions about the ecological drivers of sexual dimorphism. [ABSTRACT FROM AUTHOR]

Cranial measurements have been widely used in various studies in wildlife sciences, ranging from understanding predator ecology to wildlife forensics. However, detailed description of morphometry and sexual dimorphism of the skull of gaur Bos gaurus gaurus is lacking. The present study was undertaken to determine the sexual dimorphism based on the cranial measurements of gaur. A total of 12 individual gaur skulls of male (n = 6) and female (n = 6) were studied in the field from the naturally deceased animals between January 2018 and December 2021 in different ranges of Bandhavgarh tiger reserve (BTR), Madhya Pradesh, India. The skull measurements were analysed using univariate and multivariate statistics to determine whether cranial dimensions could be used to differentiate male and female skulls reliably. A total of 43 morphometrical parameters grouped into nine indices were calculated. Select morphometrical parameters viz PL, GFL, AKI, LBB, LFB, GBEE, GBAN, BPOP and GTCH were significantly different (p < 0.05) between sexes, whereas GBAN were significantly higher in female skulls. The measurements demonstrated that the skull of the gaur was dolichocephalic as the profile length and the otion to otion breath in both male and female were <75% of the length. Overall, 28 linear measurements of both the sexes were statistically significant (p < 0.05; <0.01). The calculated indices revealed that the foramen magnum index in the female gaur were significantly higher. In calculated cranial indices the facial index (a) was higher in female and facial index (b) were higher in males. The two important parameters, facial breadth in facial index (a) and the greatest breadth in facial index (b) were positively correlated, though facial index (a) was statistically not significant between the sexes. The greater inner length of the foramen magnum in female skull resulted in foramen being oval whereas it was circular in males. These parameters were decisive for sexual dimorphism, skull comparison and craniological studies. This study ascertained that the frontal index and skull index had no significant influence and were not good indices for discriminating skulls between male and female. Based on the Principal Component Analysis, it was found that skull of male and female gaurs exhibits differences in cranial morphology viz. cranial profile length or total length (PL) and the least inner height of the temporal groove (LIHT). The findings of the present study provide baseline information on various craniometrical measurements of skull of gaur, indices and parameters for sex identification that can be effectively used in understanding sex biased predation ecology, provide base line information to describe variation across its geographic range, and in identifying skulls recovered in wildlife offence cases. [ABSTRACT FROM AUTHOR]

Objectives: To document frontal sinus volume (FSV) in a sample of sub‐Saharan Africans with a view to evaluating claims that such populations exhibit comparatively small sinuses. This study also addresses questions related to sexual dimorphism, incidence of sinus aplasia, and the possibility that FSV continues to increase through adulthood. Materials and methods: FSV was measured from CT scans of adult crania from the Dart Collection. Sex and age were known for each individual. Linear cranial dimensions were used to compute a geometric mean from which a scaled FSV was computed for each cranium. Results: FSV does not differ significantly between sexes, but females exhibit a higher incidence of aplasia. There is considerable variation in FSV in this sample, with the average ranking among the higher means reported for other population samples. The incidence of FS aplasia falls within the range of values recorded for other population samples. Although our study is cross‐sectional rather than longitudinal, there is strong evidence that FSV continues to increase with age throughout adulthood. Discussion: The FSV mean of our sample contradicts the notion that sub‐Saharan Africans possess small sinuses. In a global context, geography (climate and altitude) does not appear to be related to FSV. The absence of sexual dimorphism in our sample is unexpected, as significant dimorphism has been reported for most other population samples. Our results support other indications that the frontal sinus continues to expand throughout adulthood, especially in females, and that it is likely due to bone resorption. Research Highlights: Frontal sinus volume in black South Africans is comparable to that in samples from other geographic regions.Frontal sinus volume is not sexually dimorphic among South Africans.The frontal sinus continues to expand throughout adulthood in this sample. [ABSTRACT FROM AUTHOR]