Genetic Diversity And Phylogenetic Analysis Of Yak In Karakoram-Pamir Area

The yak(Bos grunniens Linnaeus)is a rare animal resource,in the world,which is mainly distributed in China's Qinghai-Tibet Plateau and surrounding high altitude areas.It is known as the "boat of the plateau" and one of the main livestock species raised by plateau farmers and herdsmen.There are 17 local varieties and 1 cultivar in the variety classification.However,none of the above varieties covered the yak population distributed in the Karakoram-Pamir Plateau region of Xinjiang,and it has become a region not covered by the geographical distribution of yak.To further clarify the level of genetic diversity and phylogenetic status.In this paper,yaks distributed in the karakoram-pamir plateau region were taken as the research objects.PCR direct sequencing and bioinformatics analysis were used to analyze the genetic diversity of the mtDNA D-loop and mtDNA Cytb complete sequences of 156 individuals from 5 groups.Using GenBank to submit tatal 510 mtDNA D-loop to analyze their phylogenetic status.The full-length sequence of the measured mtDNA Cytb gene and 10 related species of Bovine in GenBank were analyzed to explore the taxonomic status of the yak.The main conclusions are as follows:1.The mtDNA D-loop sequence of the yak population in karakoram-pamir Plateau is 890-895 bp in length,and the average proportion of the four bases of T,C,A and G are 28.7%,25.2%,32.5% and 13.6%,respectively.The A+T content(61.2%)was higher than the G+C content(38.8%),indicating that the mtDNA D-loop region of yak is rich in A+T,which is consistent with the bias of mammalian mitochondrial DNA base composition.A total of 63 polymorphic loci were detected in 156 yak individuals,including 13 single polymorphic loci with 44 haplotypes.The haplotype diversity and nucleotide diversity of yaks in karakoram-pamir plateau were 0.806 and0.01528 respectively,indicating that the yaks in karakoram-pamir Plateau had rich genetic diversity.The NJ phylogenetic tree and Network network relationship constructed by 44 haplotypes clustered two branches,indicating that karakoram-pamir Plateau has two maternal origins.(AD)four small evolutionary branches,It indicatesthat the Yak in the Karakoram-Pamir Plateau has two maternal origins.2.Phylogenetic analysis indicated that 510 sequences downloaded from the GenBank database and the measured 2 tianzhu white yak sequences and 156karakoram-pamirs analyzed in this experiment Phylogenetic trees show that 140 haplotypes are clustered into three branches,which form five small branches(a-f).The yak mtDNA D-loop sequence was composed of two distinct evolutionary lineages,indicating that the yak population in China originated from the two lineages.No correlation was found between the species and the distribution pattern of yak.he yak in karakoram-pamir Plateau plateau is less Shared with other yak species,while karakoram-pamir Plateau in branch C has a large proportion of yak population and is Shared with wild yaks,which indicates that the yak population in karakoram-pamir Plateau is unique,and the yak in karakoram-pamir Plateau may directly originate from wild yaks.3.Research on the classification status of yak,110karakoram-pamir Plateau And download 82 yak mtDNA Cytb sequences with 42 sequences of bovine subfamily representative species,construct a phylogenetic tree.the results show that the yak is first clustered with the American bison,and the branches formed are clustered with the European bison,and then clustered with the branches of the Indian bison,gayal,forest cattle,Java buffalo and common cattle and the original cattle and zebu,and finally Buffaloes converge.