Preliminary Study On The Identification And Function Of Sex-related Genes Sox9,Dmrt1 And Foxl2

Sexual reproduction is widespread in animals.The focus of this research area is gender determination and differentiation.The former is the process of establishing gender under the influence of genetic or environmental factors,and the latter is the process of transforming undifferentiated gonads into ovaries or testes.Gender development has a complex process in which various sex determinants initiate and mediate the expression of sex-differentiated genes,ultimately leading to phenotypic differences between genders.Sex determination is a critical period before sex differentiation,in which the primary signal initiates a pathway that allows the gonad to eventually differentiate into the testis or ovary.There are three main gender determination systems in gender: genetic gender determination(GSD),environmental gender determination(ESD),and a mix of GSD and ESD.In the most frequently studied mammalian mammals,this pathway of sex-differentiation involves a range of genes,such as Wt1,Sf1,SRY,Sox9,Gata4,Dmrt1 and MIH in males;WNT4,Rspo1,DAX1 and Foxl2 in females.There are many types of mollusks and there are different ways of reproduction.In bivalve molluscs,there are dioecious and hermaphroditic species,as well as species that can change gender.The main factors for sex determination can be genetic,environmental or both.Several key sex-related genes in model organisms have been identified in bivalves,including Foxl2,WNT4,FST,?-catenin,DMRT,DAX1 and SOXE.Most of them show a pattern of sexual dimorphism in the gonads and are considered to be related genes in sex differentiation.At the same time,gonad transcriptome analysis identified key candidate genes for sex determination or differentiation,such as Foxl2,WNT4,?-catenin,DMRT,DAX1,SOXE,and SOXH.These studies suggest that sex determination and differentiation genes may be veryconserved in animals.Hyriopsis cumingii is endemic to China,and more than 70% of the world's freshwater pearls are produced from Hyriopsis cumingii.The study found that male parthenogenesis has great potential in the production of Hyriopsis cumingii.In this study,Foxl2,Dmrt1 and Sox9 of Hyriopsis cumingii were used as the research object,and the full-length sequences of HcFoxl2,HcDmrt1 and HcSox9 genes were obtained by cDNA cloning.The amino acid sequences of each gene were sequenced and phylogenetically analyzed.q-PCR revealed that HcFoxl2 gene was specifically expressed in female gonads,which may be related to female sex determination and differentiation;HcDmrt1 gene was significantly expressed in male and female gonads,and was highly expressed in male gonads,suggesting that the gene may be male.Sex determination and differentiation-related genes;HcSox9 gene expression in male and female gonads is not significantly different,it is speculated that HcSox9 is not a key gene for sex determination and differentiation.The results of in situ hybridization showed that HcSox9 was signaled in male and female gonads.In the female gonads,strong signals were detected mainly in the cell membrane of the egg cells.In male gonads,the signals were mainly from sperm cells in the testis.In the female gonads,HcDmrt1 detected an expression signal on the cell membrane of the oocyte;indicating that the expression of the HcDmrt1 gene is in mature egg cells.In the male gonads,a staining signal was observed in the sperm cells in the follicular cavity;it is speculated that this gene is involved in the sperm formation process.Studies have shown that the expression of Dmrt1 gene in the gonad tissue of Pinctada margaritifera is related to the male and female gonadal differentiation,similar to our results.It is speculated that the HcDmrt1 gene is involved in the gonadal development of the Hyriopsis cumingii.HcFoxl2 has strong expression in the cell membrane,cytoplasm and follicular sac of oocytes in female gonads.These results indicate that HcFoxl2 plays a role in the development of egg blast cells,which is related to many species of Foxl2 in mammals.The results in the hypothetical follicle development in adults are consistent.Such as Oreochromis niloticus and Oryzias latipes.Significant expression signals were also detected in primary oocyteson the follicle and follicular walls;this expression of Foxl2 in cells was identical to that of follicular cells mentioned in most species.It is speculated that the HcFoxl2 gene plays an important role in the process of female sex development and differentiation.In the male gonads,a staining signal was observed in the testis,but it was not very obvious.This observed male expression is essentially consistent with that observed in other species,including hermaphrodites,where Foxl2 expression is higher in adult ovaries than in adult testes.In combination with the difference in expression of male and female gonads,it is speculated that the HcFoxl2 gene is a female-specific gene.The results of RNA interference initially tested in this experiment indicated that the interference chains obtained by the screening could effectively inhibit the expression of Foxl2 gene in female gonads of Hyriopsis cumingii.The inhibitory effect in male gonads was not obvious,This provides some theoretical and experimental basis for further study of the HcFoxl2 gene.