Screening Of Related Genes Regulating Gene-temperature Dependent Sex Determination In Nile Tilapia Based On Brain Transcriptome Data

The type of sex determination of vertebrates can be divided into two categories: genetic gender determination(GSD)and environmental gender determination(ESD).Temperature Sensitivity Determination(TSD)is called because temperature is the most influential factor for gender determination among various environmental factors.The sex determination of some fish is controlled by both genetics and temperature,and has a sex chromosome,called a mixed type of genetic sex determination and temperature sex determination(GSD+TSD).For example,Nile tilapia is a kind of GSD+TSD.Fish.Previous studies have found that high temperature can affect the expression of many female sex-related genes in the gonads such as Cyp19a1 a and male sex-related genes such as Dmrt1,however,few studies have conducted temperature treatment during the thermal phase(TSP)on the brain.The effect of related gene expression.In this study,three whole female families(F1-F3)were established.The male rates of three whole female families after high temperature treatment were 65%(F1),74%(F2)and87%(F3),respectively.From the above three families,the F3 family with the highest male rate after high temperature treatment was selected.At 21 dpf,the brain tissues of the control female fish group(FC)and the high temperature treatment group(FT)in the F3 family were used for transcriptome analysis.At the same time,a normal family was established.At 21 dpf,the male and female of the juvenile fish were identified by molecular marker technique,and the brain tissue of the male individual was selected as the control male fish group(MC)for transcriptome analysis.High-throughput analysis showed that 351,146,876 clean reads were obtained from the FC,FT,and MC groups.Comparing the three groups,the results showed that the number of differentially expressed genes(DEG)obtained in the FC/FT,FC/MC and MC/FT comparison groups were 105,3164 and 4666,respectively,of which FC/FT groupThere are 87 DEGs in the middle and up to 18 in the DEG;there are 1123 DEGs in the FC/MC group and 2041 DEG in the down-regulated DEG;3354 DEGs in the MC/FT group,and the DEG in the down-regulated 1312.The Venn plot shows that the number of DEGs for FC/FT and FC/MC,FC/FT and MC/FT,FC/MC and MC/FT overlap is 31,88 and 2534,respectively.In addition,the DEG of each comparison group was further analyzed and screened by GO,KEGG and trend analysis.Among them,GO analysis indicates that DEG mainly involves biological functions such as single-organism process,metabolic process,cellular process and Binding.Most DEGs are mainly enriched in biological pathways such as Cell adhesion molecules,Metabolic pathways,and Biosynthesis of antibiotics.A total of 16 DEGs were screened by trend analysis,and their mRNA expression levels showed significant down-or up-regulation after high-temperature treatment and reached a level similar to MC.Among the 16 DEGs,LOC100699848(lysine specific demethylase 6A)and Jarid2 both contain the JmjC domain,indicating that the JmjC domain may play an important role in the temperature treatment of Nile tilapia.Finally,9 differentially expressed genes were verified by real-time fluorescent quantitative PCR(qRT-PCR).The results of this study will provide important clues for studying the molecular mechanisms of fish GSD + TSD.