Development Of SNP Markers And Population Genetics Analysis Of Schizothorax Curvilabiatus Based On SLAF-seq Technology

Schizothorax curvilabiatus belongs to the genus Schizothorax of the family Cyprinidae.It is distributed in the main tributaries of the lower reaches of the Yarlung Zangbo River and its tributary and the Chayu River,which is endemic to Tibet.In this study,we first constructed a SLAF library of Schizothorax curvilabiatus by using Specific-locus Amplified Fragment Sequencing technology(SLAF-seq),developed a large number of single nucleotide polymorphism(SNP)sites.Then we analyzed population genetic diversity of two Schizothorax curvilabiatus groups and kinship between them.And the function of the selected genes were excavated.The causes of the above results were analyzed.The main conclusions obtained are as follows:1.The experiment selected RsaI+Hae ? endonuclease combination to digest the arc-lip-bone fish genome,and used Oryza sativa ssp.japonica as a control group to sequence 20 Schizothorax curvilabiatus by Illumina sequencing platform.379129 SLAF tags were obtained,and the average sequencing depth of the tags was 147.94 x,of which 156262 were polymorphic SLAF tags.And a total of 506990 SNP sites were obtained.2.From the experimentally obtained 506990 SNP markers,according to the INT? 0.5,the MAF> 0.05,154224 highly consistent SNP markers were screened for population genetic analysis.The number of observed alleles,expected alleles,observed heterozygosity,expected heterozygosity,Nei's diversity index,Shannon index,and polymorphism information of Motuo and Yigonghu populations were respectively: 2.000,1.6077,0.3577,0.3586,0.4061,0.5371,0.2877 and 2.000,1.5149,0.2867,0.3149,0.3283,0.4842,0.2569.3.By using the above SNP markers to analyze the linkage disequilibrium,phylogenetic analysis,principal component analysis,population cluster analysis and selective clearance analysis of the two populations,the genetic diversity of the Motuo population was higher than Yigong's.And there is only moderate genetic differentiation between the two groups,the genetic relationship is relatively close.There may also be a small number of individuals communicating with each other between the two groups.4.By annotating the selectively selected genes from the KOG,GO,and KEGG databases and performing enrichment analysis,it was found that the protein function category with the largest number of genes in the KOG functional classification is the “Signal transduction mechanisms”.Mechanism,GO functional annotation enrichment shows that the most variable gene between the two populations is the “cellular metabolic process”,and the KEGG pathway functional annotation enrichment indicates that the biggest difference between the two populations is the digestion of “protein digestion and absorption”.We speculate that there may be a gap in feed abundance of the environment in which the two groups live,which is the main reason that the population genetic diversity of the fish in the Yigonghu is lower than that of the Motuo population.This gap may also be one of the reasons for the individual of the Schizothorax curvilabiatus in the Motuo to trace the Yigonghu.