Sexual Development最新文献

Introduction: Previous research has shown substantial variation in sexual dimorphism of facial structure and skin color across human populations. This study investigates sexual dimorphism in both facial shape and skin color in understudied populations from the Horn of Africa - Somalis and Ethiopians - focusing on the relationship between facial morphology and pigmentation traits.

Methods: Standardized frontal and profile photographs were collected from participants and analyzed using geometric morphometrics. Sexual shape dimorphism (SShD) was calculated by projecting each individual's facial shape onto a vector connecting average male and female shapes in Procrustes-aligned morphospace; higher values indicate more masculine morphology. Sexual color dimorphism (SCoD) was computed similarly, by projecting individual skin color values (from forehead and cheeks) onto a vector defined by average male-female difference in the CIE Lab* color space. Trajectory analysis and Bayesian hierarchical modelling were performed to examine associations between SShD and SCoD.

Results: Significant sexual dimorphism was detected in both facial shape and skin color across both populations. Male faces tended to be more robust and darker, while female faces were more gracile and lighter-skinned. However, despite group-level sex differences, individual-level associations between facial structure and skin pigmentation were weak or absent. Somali participants exhibited greater dimorphism in skin color compared to Ethiopians, while facial shape dimorphism remained consistent between groups.

Conclusion: Both target populations revealed significant sexual dimorphism in both structural and pigmentation facial traits. However, in contrast to previous findings reported in certain West African populations, we found no statistically reliable association between these two traits at the individual level. This decoupling may indicate distinct evolutionary or ecological pressures shaping morphological and pigmentation traits. Our findings suggest that no universal trade-off or consistent relationship exists between morphological and pigmentation components of sexual dimorphism across human populations.

Introduction: Sexual conflict is pervasive and can favor the evolution of differential gene expression patterns between males and females. The evolution of such sex-biased expression patterns is constrained by pleiotropic functions of differentially expressed genes, such as widespread expression across tissues.

Methods: We investigated sex-biased gene expression and its relationship to tissue specificity in reproductive and somatic organs in the Northern pipefish, Syngnathus fuscus, a polygynandrous species with extreme paternal care and no evidence of sex chromosomes - conditions ripe for intra-locus sexual conflict.

Results: We found patterns of sex-biased expression in the gonads, liver, and gills of the Northern pipefish, with the largest number of sex-biased genes identified in the gonads. In general, sex-biased genes were only more tissue-specific in the reproductive tissues (gonads), but not in either of the somatic tissues (liver or gills). Sex-biased genes with evidence of branch-specific selection were also more tissue specific.

Discussion: We highlight the potential for different sex-specific selection pressures to be acting on each tissue type as there were widespread differences in the protein classes represented by sex-biased genes across both organs and sexes, although sex-biased genes did not experience stronger episodic selection than unbiased genes. Furthermore, our results support the hypothesis that broad expression can constrain the molecular evolution of a gene. The work presented here supports the potential for sex-biased gene expression to act as a mechanism for phenotypic differentiation between the sexes and increases our knowledge of patterns of gene expression in an unusual group of fishes.

Introduction: The Y chromosome-linked gene sult1st6y (a homolog of the estrogen sulfotransferase gene) has recently been identified in Thunnus, a genus characterized by an XX/XY sex determination system. This study examined whether sult1st6y is a sex-determining gene in bluefin tuna (T. orientalis).

Methods: The expression of sult1st6y was examined using polymerase chain reaction analyses and in situ hybridization. Sult1st6y expression in masculinized XX testes produced by aromatase inhibitor administration and the expression profile of the sult1st6y mutant, which was produced using CRISPR/Cas9, were examined.

Results: Sult1st6y was specifically expressed in XY gonads during sex differentiation. The onset of sult1st6y expression preceded that of other genes promoting sex differentiation. Sult1st6y expression was not detected in masculinized XX testes, indicating that gonads can differentiate into testes without sult1st6y if estrogens are depleted. The Sult1st6y mutant XY gonad showed a gene expression pattern similar to that of wild-type XX gonads.

Discussion/conclusion: Our results collectively suggest that sult1st6y is at the top of the molecular cascade that regulates gonadal sex differentiation. Sult1st6y may trigger testicular differentiation by deactivating estrogens, although its biochemical activity should be examined. This study provides evidence that sult1st6y is a major candidate sex-determining gene in tuna.

Introduction: Sex-specific genotype and early organization can influence the expression of sexually dimorphic traits in vertebrates. We tested these hypotheses in male-typical behaviour and rapid change to bright colouration in the veiled chameleon (Chamaeleo calyptratus) with XX/XY sex chromosomes.

Methods: Hormonal manipulations included castration with and without testosterone replacement and testosterone administration in females.

Results: Long-term testosterone treatment induced male-typical sexual behaviour and an ability to switch to bright colouration in females, while castration suppressed these traits in males. These observations document that elevated testosterone alone is sufficient for the expression of these traits in both males and females. Surprisingly, high testosterone levels led to indiscriminate courtship behaviour, with frequent mating attempts directed at conspecifics regardless of their sex and testosterone level in both home cages and neutral arenas. This unexpected behaviour suggests that visual cues, such as body and head-casque size, may not reliably guide sex recognition during short distance encounters.

Conclusion: The dependence of the male-typical sexual behaviour and colour change on the elevated androgen levels contrast sharply with earlier results on skeletal traits (body size and head-casque size), which are fully developed in castrated males, demonstrating that the ontogeny of the sex-typical phenotype involves different mechanisms in the emerging model species of chameleons.

Introduction: The SOX9 gene encodes a transcription factor that acts downstream of the Y-linked SRY gene and plays a pivotal role in fetal testis development. Duplication of SOX9 or its regulatory sequences is a known cause of testicular or ovotesticular disorder of sex development (DSD) in chromosomal females (XX DSD). Numerous reports have described canine XX DSD, characterized by virilization (e.g., enlarged clitoris) and the presence of testes or ovotestes. This study aimed to identify SOX9 variants in a cohort of French Bulldogs with XX (SRY-negative) DSD.

Methods: In total, 27 DSD dogs were studied, including 19 with abdominal, spermatogenetically inactive testes; four with inactive testis and ovotestis; one with inactive testis and ovary; one with ovotestes; and in two dogs, histological analysis could not be performed. Moreover, 24 control females of the same breed, all with normal external female genitalia, were included.

Results: Three known DNA variants were identified in SOX9: a 3 bp insertion/deletion (CCT/---, rs852828782), a T>C SNP (rs22704771) in the 5' UTR, and an intronic T>G SNP (rs9183825). These variants were rare, and their distribution was similar in both cohorts. Additionally, the number of SOX9 gene copies was assessed using ddPCR. A single XX DSD case with additional skeletal malformations carried three copies of SOX9, while all other cases and control females had two copies.

Conclusion: We conclude that SOX9 duplication is a rare cause of XX DSD in French Bulldogs, and that the identified sequence variants in this gene are not associated with the disorder.

Introduction: Gonadal development and reproduction are under the control of the endocrine system, which acts along the brain-pituitary-gonad (BPG) axis. Besides well-known regulators of the BPG axis, such as the gonadotropin-releasing hormone, follicle-stimulating hormone, and luteinizing hormone, the anti-Müllerian hormone (Amh) came into the focus of research on the BPG axis. Amh is expressed differently in the gonads of dominant and subordinate Nile tilapia (Oreochromis niloticus) males and could be involved in the regulation of the differently developed gonads. In addition, the regulatory networks and the control of gene expression depend on microRNAs (miRNAs), an often not considered epigenetic mechanism in hormonal research.

Methods: We used a long-term, stable social hierarchy of Nile tilapia males as an experimental system to identify differentially expressed (DE) miRNAs in the testes of dominant and subordinate animals. A Dual-Luciferase Reporter Assay and in vitro analysis of amh expression in primary testis cells were used to demonstrate predicted interactions.

Results: We identified 23 DE miRNAs in the testes of dominant and subordinate males and predicted the targets in the pools of DE genes. Using these data, we placed the identified GO terms and KEGG pathways in the context of differently developed gonads under social control. The most DE miRNA, oni-miR-499, is upregulated in the testes of dominants and regulates amh expression.

Conclusion: We conclude that oni-miR-499 affects testis development via amh expression in Nile tilapia. Many miRNAs and biological processes identified in our study could be conserved mechanisms of testis development.

Introduction: Monorchidism is a rarely described condition in the horse and is not to be confused with cryptorchidism. The diagnosis is challenging and confirmed by surgery and histology in combination with hormonal assays. This report describes, to the best of the author's knowledge, the first case of monorchidism and abdominal cryptorchidism of the developed testicle in a horse.

Methods: An Irish Cob underwent laparoscopic castration for removal of bilateral cryptorchid testicles. At surgery, the horse was diagnosed as a monorchid with the testicle retained intra-abdominally. Histopathological, hormonal, molecular and cytogenetic analysis was performed. This included measuring testosterone and anti-Mullerian hormone (AMH) in serum blood, isolating genomic DNA from EDTA- and heparin-treated blood, PCR amplification of the SRY gene, metaphase chromosome preparation, and DAPI banding before metaphase analysis with fluorescence in situ hybridisation (FISH) analysis.

Results: The horse was positive for the SRY gene and had a mosaic 63,X/64,XY karyotype with the aneuploid cells being present in only 2% of metaphases. FISH showed that the missing sex chromosome of the aneuploid cell line was the Y chromosome embedded in micronuclei. An abnormal high rate of micronuclei (6.6%) was observed indicating genotoxic events and/or genome instability. Hormonal assay results confirmed that AMH was not significantly increased, suggesting that no further testicular tissue was present. Histopathology was consistent with testicular tissue displaying a Sertoli cell-only pattern with bipolar ductal structures.

Conclusion: The exact causes of monorchidism and cryptorchidism are unclear, but the elevated rate of micronuclei is clear evidence for genome instability which might have been involved in the failure of normal testicular development and descent. Future cases could further clarify the disease mechanism based on this report.

Background: 46,XX testicular/ovotesticular disorders of sexual development (T/OT DSD) are infrequent congenital conditions characterized by the presence of functional ovarian and testicular or only testicular parenchyma.

Objective: The aim of the study was to retrospectively describe clinical, hormonal, and genetic characteristics of 29 patients with 46,XX T/OT DSD (2000-2023), focusing on gonadal function, hormonal production, and long-term follow-up.

Results: Most patients (n = 25, 86.2%) presented with atypical genitalia that suggested DSD. Median age at first assessment was 0.38 years. Sex assignment was male in 21 patients without reports of discordant gender identity. Sex assignment was recommended before expert evaluation and without adequate studies in 64% of those patients with atypical genitalia (16/25). The median external masculinization score was 8 (range 4-12). During mini-puberty, LH, testosterone, AMH, and the LH/FSH ratio were above the female reference range and no different from the normal male reference range. Spontaneous puberty was observed in one female and 10 male-assigned subjects. Among the latter, pubertal virilization occurred with signs of hypergonadotropic hypogonadism and gynecomastia. Molecular studies identified the underlying mechanism in 7 patients: SRY gene was identified in two, WT1 gene variations were detected in three others, and 2 syndromic patients harbored complex chromosomal rearrangements.

Conclusion: Our findings underscore the clinical and biochemical variability in 46,XX T/OT DSD. Expert evaluation and accurate diagnostic work-up are essential prior to sex assignment and to prevent misdiagnosis and inappropriate treatments. Mini-puberty was characterized by a masculinized pattern of gonadotropin secretion. The potential for functional male pubertal development should be taken into account when making sex assignment decisions.

Introduction: The Dmrt1 gene is essential for sex determination and gonadal development across vertebrates. Despite its established role in model species, its functional dynamics and seasonal regulatory patterns remain uncharacterized in Gekko japonicus, a key species for understanding reptilian reproductive strategies. This study thus aimed to (1) elucidate its structural characteristics, (2) analyze seasonal expression profiles and sexual dimorphism of Dmrt1, and (3) define its physiological roles in reproductive cyclicity.

Methods: Total RNA was extracted from adult G. japonicus testes, and the full-length Dmrt1 transcript was obtained through 3' and 5' RACE. Bioinformatics predicted its properties, and phylogenetic analysis was conducted using PhyloSuite v1.2.3. RT-qPCR evaluated gjDmrt1 expression in male and female tissues and gonads.

Results: The gjDmrt1-encoded protein is a hydrophilic nuclear protein with a conserved 54-amino acid DM domain, exhibiting high conservation among vertebrates. RT-qPCR shows significant differential expression in male tissues, sex dimorphism favoring males, and expression peaks in April with notable periodic fluctuations.

Conclusion: This study offers critical insights into the characterization of the Dmrt1 gene in G. japonicus. The findings underscore its significant role in seasonal reproductive regulation and provide essential information for further investigation into the interactions between Dmrt1 and other candidate genes associated with gonad differentiation, as well as its regulatory mechanisms across varying environmental conditions.

Introduction: Although maternal microchimerism has been implicated in various disorders in children, its association with the risk of 46,XY disorders of sex development remains unknown.

Methods: We studied 22 boys with hypospadias using highly sensitive quantitative PCR assays. In seven cases with additional anomalies, microarray-based comparative genomic hybridization and whole-exome sequencing confirmed the lack of apparent pathogenic variants.

Results: Maternal microchimeric cells were detected in 2 patients (1.9 and 32.0 cells per 106 total cells). The results were comparable to our reference data.

Conclusion: This study argues against the significant role of maternal microchimerism in the risk of hypospadias.