Search Results (36)

In recent years, gender medicine has emerged as a field of research analyzing sex-related differences in health and disease. Biological sex, depending on sex chromosome complement, sex steroid hormones, and reproductive organs, has been demonstrated to influence human susceptibility to infections, immune responses against pathogens, the clinical severity of infectious diseases, and responses to the available treatments. Men and women differ in their chromosome set, with men having one X chromosome (XY) and women two (XX). This different genetic composition results in a sex-dimorphic expression of genes and pathways involved in immune regulation, as well as in shaping immune responses to infectious agents. Moreover, estrogen, progesterone, and testosterone, impacting cells and pathways involved in both innate and adaptive immunity, have been shown to drive sex dimorphism in infectious diseases. This narrative review aims to explore the sex-related differences in responses to infections, specifically focusing on the underlying genetic and hormonal mechanisms. Hence, aging-related changes in the immune system and their potential impact on immune responses against pathogens will be discussed. Understanding sex differences and stratifying the population according to them will open the door to precision medicine and personalized patient care. Full article

Nile tilapia, as an ideal model for studying sex differentiation, is a popular farmed fish worldwide with a stable XX/XY sex-determination system. In tilapia, ovarian differentiation is triggered by estradiol-17β (E2) production in undifferentiated gonads. In a previous study, we suggested that follicle-stimulating hormone (FSH) signaling might be involved in ovarian differentiation in Nile tilapia. In this study, we further investigated the role of FSH signaling in ovarian differentiation via aromatase expression, which converts testosterone to E2. Masculinization of XX fry by aromatase inhibitor or 17α-methyltestosterone leads to suppression of fshr expression. Feminization of XY fry by E2 treatment increased fshr expression from 15 days after hatching, when E2 treatment was terminated. XX tilapia developed ovaries harboring aromatase expression if fsh and fshr were double knockdowns by morpholino-oligo injections. Finally, the transcriptional activity in the upstream region of the aromatase gene (cyp19a1a) was further increased by FSH stimulation when HEK293T cells were co-transfected with foxl2 and ad4bp/sf1. Collectively, this study suggests that the role of FSH signaling is not critical in tilapia ovarian differentiation; however, FSH signaling may have a compensatory role in ovarian differentiation by increasing cyp19a1a transcription in cooperation with foxl2 and ad4bp/sf1 in Nile tilapia. Full article

Background: Argyrosomus japonicus, a member of the Sciaenidae family, is widely distributed across the sea areas near China, Japan, Australia, and South Africa. The aim of this study is to provide a high-quality genome with new technology and to understand the sex determination mechanism of this species. Methods: We generated a high-quality chromosome-level genome for Argyrosomus japonicus using PacBio HiFi and Hi-C sequencing technologies. To map the sex determination region, we employed re-sequencing data from 38 A. japonicus and conducted genome-wide association studies (GWASs) on sex phenotypes. Results: Utilizing Hifiasm, we assembled a 708.8 Mb genome with a contig N50 length of 30 Mb. Based on Hi-C data, these contigs were organized into 24 chromosomes. The completeness of the assembly was assessed to be 99% using BUSCO, and over 98% according to Merqury. We identified a total of 174.57 Mb of repetitive elements and annotated 24,726 protein-coding genes in the genome. We mapped a 2.8 Mb sex determination region on chromosome 9, within which we found two sex-linked markers. Furthermore, we confirmed that the XX-XY sex determination system is adopted in A. japonicus. Conclusions: The findings of this study provide significant insights into genetic breeding, genome evolution research, and sex control breeding in A. japonicus. Full article

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

The spotted scat (Scatophagus argus) is an important ornamental species with sexually biased ornamental values that favor males. Therefore, it makes sense to breed mono-male fingerlings as ornamental fish. The spotted scat has an XX/XY sex determination system; therefore, the first step in producing genetically all-male offspring should be the induction of a fertile sex-reversed XY pseudo-female, which would then be mated with a normal XY male to produce a YY super-male. However, the XY pseudo-female produced by estradiol (E₂) treatment failed due to ovarian malformations. Here, male to female sex reversal was induced in spotted scat through a combination of E₂ and an androgen inhibitor (trilostane, TR). Spotted scat fingerlings of approximately 2.8–3.5 cm were fed a diet containing both E₂ (300 µg/g) and TR (300 µg/g). The fish were treated for 90 days and then fed a normal diet until they reached one year of age, when they were sampled. Twenty-eight treated XY individuals were identified using sex-linked markers. According to their gonadal histological characteristics, these treated XY fish could be divided into three groups: males with testes (n = 21), intersex individuals with ovaries–testes (n = 3), and fully sex-reversed individuals with ovaries (n = 4). All treated XX fish (n = 8) developed into normal females. There were no obvious abnormalities in the ovaries of the XY sex-reversed fish compared to the treated XX fish. Serum 11-ketotestosterone (11-KT) levels were significantly lower in XY-reversed females and treated XX females than in XY males. Compared with XY male fish, the expression of female (42sp50, foxl2, figla, zar1, and zp2) and male (dmrt1, gsdf, amh and cyp11b2) biased genes was up- and down-regulated, respectively, in the gonads of XY-completely sex-reversed fish. Immunohistochemical results indicate that 42Sp50 was expressed in oocytes of XY-partially and completely sex-reversed fish, while strong Gsdf signals were mainly detectable in testicular somatic cells of XY-partially sex-reversed fish and XY male fish. XY females were successfully produced by the combined treatment of E₂ and TR in the spotted scat. Their fertility will be tested in the future. Full article

Jade perch (Scortum barcoo) has an XX/XY sex-determination system (SDS); however, its sex chromosomes and sex-determining region remain unknown. The recent availability of the jade perch chromosome-level genomic data provides a valuable resource for pinpointing the location of functional genes and the whole genomic structure. In this study, we conducted. In silico chromosome mapping of male-specific/linked loci of jade perch and identified a potential 11.18 Mb male-linked region localized on chromosome 19 (SBA19). Repeat annotations of the male-linked region revealed an abundance of transposable elements, particularly Ty3/Gypsy and novel repeats. Sequence analysis of this region identified a remnant of amh gene, which is considered a potential candidate for SDS in many teleosts. A duplicate copy of amh remnant was located at SBA6. These duplicated amh copies were highly similar to those of XX/XY SDS in teleosts, in which one copy of amh was identified on the Y sex chromosome. Taken all together, we hypothesize SBA19 as the putative sex chromosome and the 11.18 Mb male-linked region to be a potential male-determining region. Full article

Ancistrus is a highly diverse neotropical fish genus that exhibits extensive chromosomal variability, encompassing karyotypic morphology, diploid chromosome number (2n = 34–54), and the evolution of various types of sex chromosome systems. Robertsonian rearrangements related to unstable chromosomal sites are here described. Here, the karyotypes of two Ancistrus species were comparatively analyzed using classical cytogenetic techniques, in addition to isolation, cloning, sequencing, molecular characterization, and fluorescence in situ hybridization of repetitive sequences (i.e., 18S and 5S rDNA; U1, U2, and U5 snDNA; and telomere sequences). The species analyzed here have different karyotypes: Ancistrus sp. 1 (2n = 38, XX/XY) and Ancistrus cirrhosus (2n = 34, no heteromorphic sex chromosomes). Comparative mapping showed different organizations for the analyzed repetitive sequences: 18S and U1 sequences occurred in a single site in all populations of the analyzed species, while 5S and U2 sequences could occur in single or multiple sites. A sequencing analysis confirmed the identities of the U1, U2, and U5 snDNA sequences. Additionally, a syntenic condition for U2-U5 snDNA was found in Ancistrus. In a comparative analysis, the sequences of rDNA and U snDNA showed inter- and intraspecific chromosomal diversification. The occurrence of Robertsonian rearrangements and other dispersal mechanisms of repetitive sequences are discussed. Full article

The anti-Müllerian hormone (Amh) is a protein belonging to the TGF-β superfamily, the function of which has been considered important for male sex differentiation in vertebrates. The Japanese flounder (Paralichthys olivaceus) is a teleost fish that has an XX/XY sex determination system and temperature-dependent sex determination. In this species, amh expression is up-regulated in genetic males and in temperature-induced masculinization during the sex differentiation period. However, to the best of our knowledge, no reports on the Amh receptor (Amhr2) in flounder have been published, and the details of Amh signaling remain unclear. In this study, we produced amhr2-deficient mutants using the CRISPR/Cas9 system and analyzed the gonadal phenotypes and sex-related genes. The results revealed that the gonads of genetically male amhr2 mutants featured typical ovaries, and the sex differentiation-related genes showed a female expression pattern. Thus, the loss of Amhr2 function causes male-to-female sex reversal in Japanese flounder. Moreover, the treatment of genetically male amhr2 mutants with an aromatase inhibitor fadrozole, which inhibits estrogen synthesis, resulted in testicular formation. These results strongly suggest that Amh/Amhr2 signaling causes masculinization by inhibiting estrogen synthesis during gonadal sex differentiation in the flounder. Full article

Genetic sex-determination features male (XX/XY) or female heterogamety (ZZ/ZW). To identify similarities and differences in the molecular evolution of sex-linked genes between these systems, we directly compared the sex chromosome systems existing in the frog Glandirana rugosa. The heteromorphic X/Y and Z/W sex chromosomes were derived from chromosomes 7 (2n = 26). RNA-Seq, de novo assembly, and BLASTP analyses identified 766 sex-linked genes. These genes were classified into three different clusters (XW/YZ, XY/ZW, and XZ/YW) based on sequence identities between the chromosomes, probably reflecting each step of the sex chromosome evolutionary history. The nucleotide substitution per site was significantly higher in the Y- and Z-genes than in the X- and W- genes, indicating male-driven mutation. The ratio of nonsynonymous to synonymous nucleotide substitution rates was higher in the X- and W-genes than in the Y- and Z-genes, with a female bias. Allelic expression in gonad, brain, and muscle was significantly higher in the Y- and W-genes than in the X- and Z-genes, favoring heterogametic sex. The same set of sex-linked genes showed parallel evolution across the two distinct systems. In contrast, the unique genomic region of the sex chromosomes demonstrated a difference between the two systems, with even and extremely high expression ratios of W/Z and Y/X, respectively. Full article

Yams (Dioscorea spp.) are a pantropical genus located worldwide that constitute an important source of nutrients and pharmaceutical substances. Some Dioscorea crop species are widely grown in West Africa. One species that is mainly cultivated in Cameroon is Dioscorea dumetorum. This is a dioecious root crop whose sex-determining system was unknown until now. To address the possible presence of sex chromosomes in D. dumetorum, we performed a karyotype characterization of male and female individuals using classical and molecular cytogenetic approaches. It was determined that 2n = 40 was the most common number of chromosomes in all of the investigated samples. One chromosome pair was longer than the others in the chromosome set and was a heteromorph in male and homomorph in female individuals. This pair corresponded to sex chromosomes, and we also confirmed this with molecular cytogenetic experiments. The results of chromomycin banding revealed the presence of strong positive signals on this chromosome pair. The signals, corresponding to GC-rich DNA regions, were similar in size on the chromosomes of the female individuals, whereas they were different in size in the male individuals. This size difference in the GC-rich heterochromatin regions was also apparent in the interphase nuclei as one small and one large fluorescent spot. The results of the in situ hybridization experiment showed that these chromomycin positive signals on the sex chromosomes also corresponded to the 35S rDNA cluster. The mean 2C DNA value (genome size) obtained for D. dumentorum was 0.71 pg (±0.012), which represents a small genome size. We found no difference in the genome size between the male and female individuals. The results of this study contribute to increasing our knowledge of sex determination in D. dumetorum (standard sex-determining XX/XY system) and may have some agronomic applications. Full article

Scincoidea, the reptilian clade that includes girdled lizards, night lizards, plated lizards and skinks, are considered as a lineage with diversity in sex-determining systems. Recently, the hypothesis on the variability in sex determination in skinks and even more the absence of sex chromosomes in some of them has been rivalling. Homologous, evolutionary stable XX/XY sex chromosomes were documented to be widespread across skinks. However, sex determination in the other scincoidean families is highly understudied. ZZ/ZW sex chromosomes have been identified only in night lizards and a single species of plated lizards. It seems that although there are different sex chromosome systems among scincoidean lineages, they share one common trait: they are mostly poorly differentiated and often undetectable by cytogenetic methods. Here, we report one of the exceptions, demonstrating for the first time ZZ/ZW sex chromosomes in the plated lizard Zonosaurus madagascariensis. Its sex chromosomes are morphologically similar, but the W is clearly detectable by comparative genomic hybridization (CGH), suggesting that the Z and W chromosomes highly differ in sequence content. Our findings confirm the presence of female heterogamety in plated lizards and provides novel insights to expand our understanding of sex chromosome evolution in scincoidean lizards. Full article

Odonata have holokinetic chromosomes. About 95% of species have an XX/X0 sex chromosome system, with heterogametic males. There are species with neo-XX/neo-XY sex chromosomes resulting from an X chromosome/autosome fusion. The genus Rhionaeschna includes 42 species found in the Americas. We analyzed the distribution of the nucleolar organizer region (NOR) using FISH with rDNA probes in Rhionaeschna bonariensis (n = 12 + neo-XY), R. planaltica (n = 7 + neo-XY), and Aeshna cyanea (n = 13 + X0). In R. bonariensis and A. cyanea, the NOR is located on a large pair of autosomes, which have a secondary constriction in the latter species. In R. planaltica, the NOR is located on the ancestral part of the neo-X chromosome. Meiotic analysis and FISH results in R. planaltica led to the conclusion that the neo-XY system arose by insertion of the ancestral X chromosome into an autosome. Genomic in situ hybridization, performed for the first time in Odonata, highlighted the entire neo-Y chromosome in meiosis of R. bonariensis, suggesting that it consists mainly of repetitive DNA. This feature and the terminal chiasma localization suggest an ancient origin of the neo-XY system. Our study provides new information on the origin and evolution of neo-sex chromosomes in Odonata, including new types of chromosomal rearrangements, NOR transposition, and heterochromatin accumulation. Full article

The veiled chameleon (Chamaeleo calyptratus) is a typical member of the family Chamaeleonidae and a promising object for comparative cytogenetics and genomics. The karyotype of C. calyptratus differs from the putative ancestral chameleon karyotype (2n = 36) due to a smaller chromosome number (2n = 24) resulting from multiple chromosome fusions. The homomorphic sex chromosomes of an XX/XY system were described recently using male-specific RADseq markers. However, the chromosomal pair carrying these markers was not identified. Here we obtained chromosome-specific DNA libraries of C. calyptratus by chromosome flow sorting that were assigned by FISH and sequenced. Sequence comparison with three squamate reptiles reference genomes revealed the ancestral syntenic regions in the C. calyptratus chromosomes. We demonstrated that reducing the chromosome number in the C. calyptratus karyotype occurred through two fusions between microchromosomes and four fusions between micro-and macrochromosomes. PCR-assisted mapping of a previously described Y-specific marker indicates that chromosome 5 may be the sex chromosome pair. One of the chromosome 5 conserved synteny blocks shares homology with the ancestral pleurodont X chromosome, assuming parallelism in the evolution of sex chromosomes from two basal Iguania clades (pleurodonts and acrodonts). The comparative chromosome map produced here can serve as the foundation for future genome assembly of chameleons and vertebrate-wide comparative genomic studies. Full article

Hemp (Cannabis sativa L., 2n = 20) is a valuable crop that is successfully used as a food, technical and medicinal crop. It is a dioecious plant with an XX\XY sex determination system. Some chromosomes of C. sativa have almost the same lengths and centromeric indexes. Cytogenetic markers help to distinguish similar plant chromosomes, including sex chromosomes, which is important for the breeding process. Two repeats (CS-1 and CS-237) were used to develop labeled oligo-probes for rapid and low-cost oligo-FISH. These oligos can be recommended for use as cytological markers to distinguish sex chromosomes (X and Y) and somatic chromosome pairs 3, 6, and 8 by rapid oligo-FISH in a short time. Full article

Mandarin fish has an XX/XY sex-determination system. The female mandarin fish is typically larger than the male. Sex identification and the discovery of genes related to sex determination in mandarin fish have important theoretical significance in the elucidation of the regulation and evolutionary mechanism of animal reproductive development. In this study, the chromosome-level genome of a female mandarin fish was assembled, and we found that LG24 of the genome was an X chromosome. A total of 61 genes on the X chromosome showed sex-biased expression. Only six gonadal genes (LG24G00426, LG24G003280, LG24G003300, LG24G003730, LG24G004200, and LG24G004770) were expressed in the testes, and the expression of the other gene LG24G003870 isoform 1 in the ovaries was significantly higher than that in the testes (p < 0.01). Five (except LG24G003280 and LG24G003300) of the seven aforementioned genes were expressed at the embryonic development stage, suggesting their involvement in early sex determination. The expression of LG24G004770 (encoding HS6ST 3-B-like) was also significantly higher in female muscles than in male muscles (p < 0.01), indicating other functions related to female growth. ZP3 encoded by LG24G003870 isoform 1 increased the C-terminal transmembrane domain, compared with that encoded by other fish zp3 isoforms, indicating their different functions in sex determination or differentiation. This study provides a foundation for the identification of sex-determining genes in mandarin fish. Full article