Role In Sex Determination Research Articles

The microevolutionary response to male-limited X-chromosome evolution in Drosophila melanogaster reflects macroevolutionary patterns.

Due to its hemizygous inheritance and role in sex determination, the X-chromosome is expected to play an important role in the evolution of sexual dimorphism and to be enriched for sexually antagonistic genetic variation. By forcing the X-chromosome to only be expressed in males over >40 generations, we changed the selection pressures on the X to become similar to those experienced by the Y. This releases the X from any constraints arising from selection in females and should lead to specialization for male fitness, which could occur either via direct effects of X-linked loci or trans-regulation of autosomal loci by the X. We found evidence of masculinization via up-regulation of male-benefit sexually antagonistic genes and down-regulation of X-linked female-benefit genes. Potential artefacts of the experimental evolution protocol are discussed and cannot be wholly discounted, leading to several caveats. Interestingly, we could detect evidence of microevolutionary changes consistent with previously documented macroevolutionary patterns, such as changes in expression consistent with previously established patterns of sexual dimorphism, an increase in the expression of metabolic genes related to mito-nuclear conflict and evidence that dosage compensation effects can be rapidly altered. These results confirm the importance of the X in the evolution of sexual dimorphism and as a source for sexually antagonistic genetic variation and demonstrate that experimental evolution can be a fruitful method for testing theories of sex chromosome evolution.

Palatoscopy and odontometrics' potential role in sex determination among an adult Egyptian population sample: A pilot study.

Background: Sex determination is the first step in personal identification in the forensic field. This study aimed to evaluate sexual dimorphism by using palatal rugae pattern and odontometrics, construct an Egyptian equation for sex determination using the discriminant function analysis. Participants and methods: The study sample included 200 participants of both sexes. Maxillary arch impressions were taken with alginate impression material using stainless steel impression tray. Identification and measurements were done to study the palatal rugae pattern, dental arch dimensions, and maxillary canine. Results: There was a highly statistically significant difference between males and females with higher male values regarding the total palatal rugae number, wavy rugae number, primary rugae number, arch length, width, maxillary canine right width, maxillary canine left width, intercanine distance, and maxillary canine right index while there was a highly statistically significant difference with higher female value regarding the straight rugae numbers. Four Egyptian equations were constructed using discriminant function analysis to determine the sex of an unidentified person. Conclusions: Palatal rugae pattern, dental arch dimensions, and maxillary canine index can be considered as useful tools for sex determination in the forensic field.

Mandibular ramus and gonial angle—Identification tool in age estimation and sex determination: A digital panoramic radiographic study in north indian population

Background: Identification of the skeletal remains is of paramount importance in forensic dentistry and medico-legal investigations. Mandible may play a vital role in sex determination, as it is the most dimorphic bone of skull, which is often recovered intact. Mandibular ramus and gonial angle can be used to differentiate between sexes and age estimation. Aims and Objectives: The aim of the study was to assess the usefulness of digital panoramic radiographs to determine sex and age using linear measurements made with respect to gonial angle and ramus region in the population of north Indians. Materials and Methods: A total of 400 patients (North Indians: Males and females in equal number) were further divided into age groups 10-40 years. The linear measurements were made in ramus and gonial angle region, which were calculated by using Adobe Acrobat Reader, and findings were statistically analyzed. Results: Males showed a higher average value in terms of ramus breadth, condylar and coronoid ramus height than females. In addition, a significant positive correlation was seen between age and ramus linear measurements. Males have higher gonial angle than females and with increase in age, gonial angle decreases. In relation to gonial angle, females showed a higher gonial angle. “In addition, as age increases, decrease in gonial angle was found.”. Conclusion: In selected north Indian populace, mandibular ramus showed higher sexual dimorphism in relation with age and sex estimation. However, gonial angle can only be used as an additional tool to establish the identity of a person.

Mutation of doublesex in Hyphantria cunea results in sex-specific sterility.

The gene doublesex (dsx) plays pivotal roles in sex determination and controls sexually dimorphic development in certain insects. Importantly, it also displays a potential candidate target for pest management due to its sex-specific splicing. Therefore, we used CRISPR/Cas9-mediated gene disruption to investigate the function of dsx in Hyphantria cunea, an invasive forest pest. In the present study, we identified the dsx gene from H. cunea which showed a sex-biased expression pattern that was different from other lepidopteran insects. Referring to sex-specific functional analyses in Bombyx mori, we performed a site-specific knockout of the Hcdsx gene by using a CRISPR/Cas9 system, which induced severe abnormalities in external genitalia and some incomplete sex reversal phenotypes, which in turn led to reduced sex-specific fecundity. An alternative splicing pattern of Hcdsx was altered by CRISPR/Cas9-induced mutation, and alterations in splicing affected expression of downstream genes encoding pheromone binding protein 1, vg1 and vg2 (encoding vitellogenin), which contributed to the sex-specific sterility phenotypes in the Hcdsx mutants. The Hcdsx gene plays important roles in sexual differentiation in H. cunea. Disruption of Hcdsx induced sex-specific sterility, demonstrating a potential application in control of this pest. © 2019 Society of Chemical Industry.

Putative Mitochondrial Sex Determination in the Bivalvia: Insights From a Hybrid Transcriptome Assembly in Freshwater Mussels.

Bivalves exhibit an astonishing diversity of sexual systems, with genetic and environmental determinants of sex, and possibly the only example of mitochondrial genes influencing sex determination pathways in animals. In contrast to all other animal species in which strict maternal inheritance (SMI) of mitochondria is the rule, bivalves possess a system known as doubly uniparental inheritance (DUI) of mitochondria in which maternal and paternal mitochondria (and their corresponding female-transmitted or F mtDNA and male-transmitted or M mtDNA genomes) are transmitted within a species. Species with DUI also possess sex-associated mtDNA-encoded proteins (in addition to the typical set of 13), which have been hypothesized to play a role in sex determination. In this study, we analyzed the sex-biased transcriptome in gonads of two closely-related freshwater mussel species with different reproductive and mitochondrial transmission modes: the gonochoric, DUI species, Utterbackia peninsularis, and the hermaphroditic, SMI species, Utterbackia imbecillis. Through comparative analysis with other DUI and non-DUI bivalve transcriptomes already available, we identify common male and female-specific genes, as well as SMI and DUI-related genes, that are probably involved in sex determination and mitochondrial inheritance in this animal group. Our results contribute to the understanding of what could be the first animal sex determination system involving the mitochondrial genome.

Integrated analysis of proteomics and metabolomics reveals the potential sex determination mechanism in Odontobutis potamophila

Odontobutis potamophila is a valuable species for aquaculture in China, which shows asexually dimorphic growth pattern. In this study, the integrated proteomics and metabolomics were used to analyze the sex determination mechanism. A total of 2781 significantly different regulated proteins were identified by proteomics and 2693 significantly different expressed metabolites were identified by metabolomics. Among them, 2560 proteins and 1701 metabolites were significantly up-regulated in testes, whereas 221 proteins and 992 metabolites were significantly up-regulated in ovaries. Venn diagram analysis showed 513 proteins were differentially regulated at both protein and metabolite levels. Correlation analysis of differentially-regulated proteins and metabolites were identified by Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analysis. The results showed lipid metabolism plays an important role in sex determination. The metabolites decanoyl-CoA, leukotriene, 3-dehydrosphinganine, and arachidonate were the biomarkers in testes, whereas estrone and taurocholate were the biomarkers in ovaries. Interaction networks of the significant differentially co-regulated proteins and metabolites in the process of lipid metabolism showed arachidonic acid metabolism and steroid hormone biosynthesis were the most important pathways in sex determination. The findings of this study provide valuable information for selective breeding of O. potamophila. Significance of the studyThe male O. potamophila grows substantially larger and at a quicker rate than the female. Thus, males have greater economic value than females. However, limited research was done to analyze the sex determination mechanism of O. potamophila, which seriously hindered the development of whole-male O. potamophila breeding. In this study, four key proteins (Ctnnb1, Piwil1, Hsd17b1, and Dnali1), six most important biomarkers (decanoyl-CoA, leukotriene, 3-dehydrosphinganine, arachidonate, estrone, and taurocholate) and two key pathways (arachidonic acid metabolism and steroid hormone biosynthesis) in sex determination of O. potamophila were found by integrated application of iTRAQ and LC-MS techniques. The results give valuable information for molecular breeding of O. potamophila in aquaculture.

Characterization of deoxyribonucleic methylation and transcript abundance of sex-related genes during tempera ture-dependent sex determination in Mauremys reevesii†.

A number of genes relevant for sex determination have been found in species with temperature-dependent sex determination. Epigenetics play a key role in sex determination, but characterization of deoxyribonucleic acid methylation of sex-related genes on temperature-dependent sex determination remains unclear. Mauremys reevesii is a typical species with temperature-dependent sex determination. In this study, we analyzed the Cytosine Guanine (CpG) methylation status of the proximal promoters, the messenger ribonucleic acid expression patterns and the correlation between methylation and expression levels of Aromatase, Forkhead box protein L2, Doublesex and mab3-related transcription factor 1, sex-determining region on Y chromosome-box 9, and anti-Müllerian hormone, which are key genes in sex determination in other species. We also analyzed the expression level of genes that encode enzymes involved in methylation and demethylation. The expression levels of Aromatase and Forkhead box protein L2 at the female producing temperature were higher than those at the male producing temperature; the expression levels of Doublesex and mab3-related transcription factor 1, sex-determining region on Y chromosome-box 9, and anti-Müllerian hormone were higher at MPT. The expression of some genes involved in methylation and demethylation is significantly different between male producing temperature and female producing temperature. The expression of messenger ribonucleic acid of genes involved in deoxyribonucleic acid methylation and demethylation affected by temperature, together with other factors, may change the methylation level of the regulatory regions of sex-related genes, which may further lead to temperature-specific expression of sex-related genes, and eventually affect the differentiation of the gonads.

Mutation of doublesex induces sex-specific sterility of the diamondback moth Plutella xylostella

Doublesex (dsx)the downstream gene in the insect sex determination pathway, plays a critical role in sexual differentiation and development. The functions of dsx have been characterized in several model insect species. However, the molecular mechanism and functions of sex determination of dsx in Plutella xylostella, an agricultural pest, are still unknown. In present study, we identified a male-specific and three female-specific Pxdsx transcripts in P. xylostella. Phylogenetic analyses and multiple sequence alignment revealed that Pxdsx is highly conserved in lepidopterans. The CRISPR/Cas9 technology was used to induce mutations in the male-specific isoform, the female-specific isoform, and common regions of Pxdsx. Disruptions of Pxdsx sex-specific isoforms caused sex-specific defects in external genitals and partial sexual reversal. In addition, we found that female specific transcripts were detected in PxdsxM male mutants and male-specific transcripts were detected in PxdsxF female mutants. Mutations also caused changes in expression of several sex-biased genes and induced sex-specific sterility. This study demonstrates that Pxdsx plays a key role in sex determination of P. xylostella and suggests novel genetic control approaches for the management of P. xylostella.

Phylogenetic analysis and embryonic expression of panarthropod Dmrt genes

BackgroundOne set of the developmentally important Doublesex and Male-abnormal-3 Related Transcription factors (Dmrt) is subject of intense research, because of their role in sex-determination and sexual differentiation. This likely non-monophyletic group of Dmrt genes is represented by the Drosophila melanogaster gene Doublesex (Dsx), the Caenorhabditis elegans Male-abnormal-3 (Mab-3) gene, and vertebrate Dmrt1 genes. However, other members of the Dmrt family are much less well studied, and in arthropods, including the model organism Drosophila melanogaster, data on these genes are virtually absent with respect to their embryonic expression and function.ResultsHere we investigate the complete set of Dmrt genes in members of all main groups of Arthropoda and a member of Onychophora, extending our data to Panarthropoda as a whole. We confirm the presence of at least four families of Dmrt genes (including Dsx-like genes) in Panarthropoda and study their expression profiles during embryogenesis. Our work shows that the expression patterns of Dmrt11E, Dmrt93B, and Dmrt99B orthologs are highly conserved among panarthropods. Embryonic expression of Dsx-like genes, however, is more derived, likely as a result of neo-functionalization after duplication.ConclusionsOur data suggest deep homology of most of the panarthropod Dmrt genes with respect to their function that likely dates back to their last common ancestor. The function of Dsx and Dsx-like genes which are critical for sexual differentiation in animals, however, appears to be much less conserved.

Runs of homozygosity and testicular cancer risk.

Testicular germ cell tumour (TGCT) is highly heritable but>50% of the genetic risk remains unexplained. Epidemiological observation of greater relative risk to brothers of men with TGCT compared to sons has long alluded to recessively acting TGCT genetic susceptibility factors, but to date none have been reported. Runs of homozygosity (RoH) are a signature indicating underlying recessively acting alleles and have been associated with increased risk of other cancer types. To examine whether RoH are associated with TGCT risk. We performed a genome-wide RoH analysis using GWAS data from 3206 TGCT cases and 7422 controls uniformly genotyped using the OncoArray platform. Global measures of homozygosity were not significantly different between cases and controls, and the frequency of individual consensus RoH was not significantly different between cases and controls, after correction for multiple testing. RoH at three regions, 11p13-11p14.3, 5q14.1-5q22.3 and 13q14.11-13q.14.13, were, however, nominally statistically significant at p<0.01. Intriguingly, RoH200 at 11p13-11p14.3 encompasses Wilms tumour 1 (WT1), a recognized cancer susceptibility gene with roles in sex determination and developmental transcriptional regulation, processes repeatedly implicated in TGCT aetiology. Overall, our data do not support a major role in the risk of TGCT for recessively acting alleles acting through homozygosity, as measured by RoH in outbred populations of cases and controls.

Consequences of Y chromosome microdeletions beyond male infertility

The human Y chromosome plays a central role in sex determination and spermatogenesis. The azoospermia factor (AZF) loci on the Y chromosome contain genes that were thought to be testis specific with their deletions leading to spermatogenic failure. However, beyond the testis, the AZF genes (mainly those in AZFa and AZFb loci) are widely expressed in multiple tissues. Further, these genes are predicted to play roles in processes such as gene regulation and protein synthesis. These observations suggest that the AZF genes may have functions beyond regulation of fertility. Three major areas have emerged where alternations in AZF genes have effects beyond infertility. (1) Poor-quality embryos are generated in assisted reproduction when sperm from men harboring Y chromosome microdeletions are used, (2) a higher preponderance of neuropsychiatry disorders is observed in men with deletions in AZF genes, and (3) copy number variations and altered expression of AZF genes are found in several cancers. While ourdata is preliminary and observational in nature, systematic studies are required to address how genetic alterations in the Y chromosome can affect the health of men beyond infertility. This information will provide a different perspective in the area of androgenetics and have implications in devising strategies for maintaining the overall well-being of infertile males.

Genomic organization and sexually dimorphic expression of the Dmrt1 gene in largemouth bass (Micropterus salmoides).

Doublesex and Mab-3 related transcription factor (Dmrt) genes play important roles in the process of sex determination and differentiation. In this study, a Dmrt1 gene open reading frame sequence was obtained from the gonadal transcriptome data of largemouth bass (Micropterus salmoides), and identified by cloning and sequencing. The ORF of Dmrt1 is 900 bp long, encodes 298 amino acids, and contains the DM region which is characteristic of Dmrt1. Full gDNA sequence of Dmrt1 was composed of five exons and four introns. RT-PCR and Q-PCR analysis of Dmrt1 were conducted in eight tissues and three developmental stages of mature male and female individuals. In situ hybridization was used to locate the expression of Dmrt1 in the testis and ovary of largemouth bass. The results showed that Dmrt1 was highly expressed in the testis of mature fish, but only weakly expressed in other tissues such as heart, liver, and brain, and exhibited gender dimorphism in the gonads of male and female fish at different stages. Furthermore, the expression level in female fish was very low and decreased gradually with ovary maturation. In situ hybridization indicated positive signals were found in early oocytes, but not in mature oocytes, while strong positive signals were found in all types of mature testis cells. The study showed that the sequence and structure of Dmrt1 were highly conserved and exhibited significant gender dimorphism in largemouth bass, as in other fish species. It is suggested that Dmrt1 plays an important role in sex determination and differentiation in largemouth bass.

Sexual Dimorphism in Permanent Maxillary and Mandibular Canine of Medical Students in Gandaki Medical College, Nepal

Introduction: Gender determination is important for identification in forensic practice. Odontometrics plays an important role in sex determination in young individuals where secondary sexual characters are yet to be developed.&#x0D; Objective: The objective was to re-evaluate the previous finding of the sexual dimorphism in Mesiodistal (MD) and Buccolingual (BL) dimension of maxillary and mandibular canine in the study population being Medical Students of Medical College in province 4 of Nepal.&#x0D; Methodology: This is a cross sectional study conducted on the study cast of 40 male and 40 female medical students of academic year 2017/18 of Gandaki Medical College, Nepal, of age group 18-24 from October to December 2017. The MD and BL dimensions of all the four canines were measured using digital vernier's caliper. Data were compared using descriptive statistics, student's t-test and paired sample t test. P&lt;0.05 was found statistically significant.&#x0D; Results: Statistically significant sexual dimorphism was found in MD and BL dimension of maxillary and mandibular canine with males' canine measuring larger than females'. The left mandibular canine was found to be the most dimorphic in term of BL dimension among the canines.&#x0D; Conclusion: The present study exhibited the buccolingual dimension of the left mandibular canine as the most dimorphic tooth. Further studies using large representative sample from all the provinces has to be conducted to quantify and generalize the result among the Nepalese Dentition.

A novel approach for sex determination using palmar tri-radii: A pilot study

Palmprints are often encountered on the scene of crime. It can play a key role in sex determination (male or female), which may help in the process of elimination and hence in narrowing down the suspect pool during forensic investigation. In the present study, 300 bilateral palmprints collected from 150 healthy consenting adults (75 males and 75 females) belonging to heterogeneous population of central India were examined. The distance between the palmar tri-radii (deltas) 'a', 'b', 'c', 'd' to the axial tri-radius 't' were studied individually as well as combined. Applying t-test, the results were found to be statistically significant (p < 0.05). Probability densities for men and women derived from the frequency distribution were used to calculate the likelihood ratio and posterior probabilities of sex designation for the given combined abcd-t distance for subjects using Baye's theorem. For left as well as right palmprint, a combined distance of ≤30 cm will have a higher probability of belonging to a female donor (p = 0.99) while, a combined distance of ≥32.5 cm will be more indicative of the print belonging to a male donor (p = 0.99).

Differentiation roadmap of embryonic Sertoli cells derived from mouse embryonic stem cells

BackgroundEmbryonic Sertoli cells (eSCs) play an important role in sex determination and in male gonad development which makes them a very useful cell type for therapeutic applications. However, the deriving mechanism of Sertoli cells has been unclear and challenging to create a large number of quality eSCs. Therefore, this study aimed to create the eSCs induced from mouse embryonic stem (mES) cells by regulating defined factors and to explore the relevant regulatory mechanism.MethodsSix inducing factors, Sry, Sox9, SF1, WT1, GATA4, and Dmrt1, were respectively transduced into mES cells by lentiviral infection according to the experimental design. The test groups were identified by development stage-specific markers, AMH, Emx2, SF1, and FasL, using flow cytometry. Induced eSCs were determined by FasL and AMH biomarkers under immunofluorescence, immunocytochemistry, and flow cytometry. Moreover, the pluripotency markers, gonad development-related markers, epithelial markers and mesenchymal markers in test groups were transcriptionally determined by qPCR.ResultsIn this study, the co-overexpression of all the six factors effectively produced a large population of eSCs from mES cells in 35 days of culturing. These eSCs were capable of forming tubular-like and ring-like structures with functional performance. The results of flow cytometry indicated that the upregulation of GATA4 and WT1 contributed to the growth of somatic cells in the coelomic epithelium regarded as the main progenitor cells of eSCs. Whereas, SF1 facilitated the development of eSC precursor cells, and Sry and Sox9 promoted the determination of male development. Moreover, the overexpression of Dmrt1 was essential for the maintenance of eSCs and some of their specific surface biomarkers such as FasL. The cellular morphology, biomarker identification, and transcriptomic analysis aided in exploring the regulatory mechanism of deriving eSCs from mES cells.ConclusionConclusively, we have elucidated a differentiation roadmap of eSCs derived from mES cells with a relevant regulatory mechanism. Through co-overexpression of all these six factors, a large population of eSCs was successfully induced occupying 24% of the whole cell population (1 × 105 cells/cm2). By adopting this approach, a mass of embryonic Sertoli cells can be generated for the purpose of co-culture technique, organ transplantation, gonadal developmental and sex determination researches.

Sex biased expression of anti-Mullerian hormone (amh) gene in a live bearing fish, Gambusia holbrooki: Evolutionary implications and potential role in sex differentiation.

The amh, a member of transforming growth factor-β (TGF-β) family, is known to play a critical role in vertebrate male sex differentiation, with its paralogue/s evolving to determine sex in few heterogametic (XX/XY) teleosts. However, it remains relatively unexplored in the reproductively unique live bearing teleosts. Therefore, this study comparatively examined the structure and content of G. holbrooki amh as well as characterised its expression. A paralogous Y-specific amh (amhy) was not detected, suggesting an unlikely role in sex determination. Two transcripts (1.4 and 1.5 kb) were detected in adults: the larger (1.5 kb) retaining intron 5, coding for a truncated AMH-N and no TGF-β domain. The small (1.4 kb) transcript, had both domains intact and clustered with members of Poeciliidae. In contrast to other vertebrates, a higher conservation between the N- rather than the C- terminus of amh in Poeciliidae was observed, suggesting an adaptation that may be unique to live bearing teleosts. The amh expression was 6 times higher in brain of both sexes and testis compared with ovaries (p = .001). Intriguingly, female splenic tissues showed 10 times higher expression (p = .006) and such female bias splenic expression has not been reported in any teleosts. Ontogenic expression was 25 times higher in male embryos at gastrulation stage (p = .001), much earlier than those reported in egg-laying teleosts. Such heightened expression in male embryos suggests a repressive role associated with proliferation and migration of primordial germ cells (PGCs) that are known to occur earlier at blastulation in teleosts-potentially influencing gonadal fate.

Amelogenin (genetic marker) role in sex determination of human

The ability to determine the sex of an individual based on DNA evidence can be crucial in instances such as identification of victims of mass disaster, missing persons investigations, and sexual assault cases. The Y chromosome marker Amelogenin is currently in widespread use for determination of chromosomal sex of an unknown DNA donor and differentiating the relative contributions of male and female DNA in a mixed forensic sample. However, many cases of the failure of the Amelogenin marker to correctly determine the sex of DNA donors have been reported, causing the usefulness of the Amelogenin marker in forensics to be questioned. In this paper we review use of Amelogenin as a marker for sex identification in forensics and describe four additional Y chromosome markers, sex-determining region Y (SRY), chromosome or the presence of specific reproductive or secondary sex characteristics.

Oestrogen differentially modulates lymphoid and myeloid cells of the European sea bass in vitro by specifically regulating their redox biology

Besides their obvious role in sex determination and reproduction, oestrogens display a prominent and complex immunomodulatory role across all vertebrates. To date, our knowledge on the oestrogenic immunomodulation in non-mammalian species is, however, scarce. In both teleosts and mammals, the direct immunomodulatory function of oestrogen is underscored by the presence of multiple oestrogen receptor subtypes in the various immune cells. For a better understanding of the regulatory processes, we investigated the oestrogen receptor expression in two major lymphoid organs of European sea bass: the head-kidney and the spleen. All oestrogen receptor subtypes, including nuclear and membrane oestrogen receptors, were present in both immune organs as well as in the isolated leucocytes. The same findings have been previously made for the thymus. To determine the oestrogen responsiveness of the different immune cell populations and to evaluate the importance of non-genomic and genomic pathways, we assessed the kinetics and the concentration dependent effects of 17β-oestradiol on isolated leucocytes from the head-kidney, the spleen and the thymus in vitro. Given the importance of reactive oxygen species as signalling and defence components in mammalian immune cells, the oxidative burst capacity, the redox status and the viability of both lymphoid and myeloid cells were measured by flow cytometry. The treatment with 17β-oestradiol specifically modulated these parameters depending on (1) the time kinetic, (2) the concentration of 17β-oestradiol, (3) the immune cell population (lymphoid and myeloid cells) as well as (4) the lymphoid organs from which they originated. The observed in vitro oestrogenic effects as well the presence of various oestrogen receptor subtypes in the immune cells of sea bass suggest a complex and direct oestrogenic action via multiple interconnected oestrogen-signalling pathways. Additionally, our study suggests that the oestrogenic regulation of the sea bass immune function involves a direct and tissue specific modulation of the immune cell redox biology comprising redox signalling, NADPH-oxidase activity and H2O2-permeability, thus changing oxidative burst capacity and immature T cell fate because oestrogen impacted thymocyte viability. Importantly, immune cells from both primary and secondary lymphoid organs have shown specific in vitro oestrogen-responsiveness. As established in mammals, oestrogen is likely to be specifically and directly involved in immature T cell differentiation and mature immunocompetent cell function in sea bass too.

RNA-Seq analysis of gynoecious and weak female cucumber revealing the cell cycle pathway may regulate sex determination in cucumber

This study aims to investigate key genes involved in molecular regulatory networks of cucumber sex determination. Genome-wide high-throughput RNA sequencing was performed for young apical buds of gynoecious and weak female cucumber at three growth stages (one-leaf one-bud, three-leaf one-bud, and five-leaf one-bud). Seven comparisons from the same cultivar at three different stages and at the same stage between the two cultivars were analyzed, and the results revealed that compared with differentially expressed genes (DEGs) in weak female cucumber, more genes were upregulated at the one-leaf one-bud stage and downregulated at the three-leaf one-bud stage in gynoecious cucumber. In addition, there were four kinds of gene expression trends (0, 1, 6, and 7), which were significantly enriched in gynoecious cucumber, while only two kinds of gene expression trends (5 and 6) were significantly enriched in weak female cucumber. Together with the data of the Gene Ontology (GO), pathway, gene expression trends and qRT-PCR, nine genes were identified and considered as candidate genes that may be involved in sex differentiation regulation in cucumber. These genes included Cs-MCM6, Cs-ACT3, Cs-XRCC4, Cs-MCM2, Cs-CDC45, Cs-Dpri, Cs-H2B, Cs-CDC20 and Cs-CNGC1. Among these genes, five genes (Cs-MCM6, Cs-MCM2, Cs-CDC45, Cs-Dpri, and Cs-CDC20) were involved in the cell cycle pathway, suggesting that the cell cycle pathway may play an important role in sex determination in cucumber.

Female Sex Development and Reproductive Duct Formation Depend on Wnt4a in Zebrafish.

In laboratory strains of zebrafish, sex determination occurs in the absence of a typical sex chromosome and it is not known what regulates the proportion of animals that develop as males or females. Many sex determination and gonad differentiation genes that act downstream of a sex chromosome are well conserved among vertebrates, but studies that test their contribution to this process have mostly been limited to mammalian models. In mammals, WNT4 is a signaling ligand that is essential for ovary and Müllerian duct development, where it antagonizes the male-promoting FGF9 signal. Wnt4 is well conserved across all vertebrates, but it is not known if Wnt4 plays a role in sex determination and/or the differentiation of sex organs in nonmammalian vertebrates. This question is especially interesting in teleosts, such as zebrafish, because they lack an Fgf9 ortholog. Here we show that wnt4a is the ortholog of mammalian Wnt4, and that wnt4b was present in the last common ancestor of humans and zebrafish, but was lost in mammals. We show that wnt4a loss-of-function mutants develop predominantly as males and conclude that wnt4a activity promotes female sex determination and/or differentiation in zebrafish. Additionally, both male and female wnt4a mutants are sterile due to defects in reproductive duct development. Together these results strongly argue that Wnt4a is a conserved regulator of female sex determination and reproductive duct development in mammalian and nonmammalian vertebrates.