Study On The Variation Characteristics Of HIF-2α Gene Sequences In Gansu Alpine Merino And Hu Sheep

Hypoxia inducible factor(HIFs) is an oxygen dependent transcriptional activator,it is composed by a regulated expression subunit α(HIF-α) and a persistent expression subunit β(HIF-β). It plays a key role in the cellular hypoxia regulation. HIF-2α is a member of the HIFs gene family, which is closely related to the high altitude indigenous population and animal adaptation to high altitude hypoxia environment.We tested the SNPs about three different regions(exon 8, exon 9 and exon 11) in the Gansu Alpine Merino and Hu Sheep of HIF-2α gene by using PCR-SSCP technique. We analyzed the sequence variation and other molecular genetic characteristics in HIF-2α gene.The main results and conclusions are as follows:(1)There were 27 variable sites in the three detected regions in the Gansu Alpine Fine Wool Sheep and Hu Sheep of HIF-2α gene, two sites were base insertion and accounting for 7.4% of the mutations; there were twenty base transitions,accounting for 74.1% of the mutations; five sites occurred base transversion,accounting for 18.5% of the mutations. The PIC values of the 3 detection regions in the two sheep breeds of HIF-2α gene were all above 0.5, which were highly polymorphic.(2)We had the PCR-SSCP results of the 3 detection regions of HIF-2α gene in Gansu Alpine Fine Wool Sheep and Hu Sheep: There were 4 alleles detected,combined nine genotypes in exon8. The dominant alleles of the two sheep breeds were B(60.59%) and A(39.57%), and the dominant genotypes were BB(48.00%) and AB(23.56%). There were five alleles detected, combined eight genotypes in exon 9.The dominant alleles of the two sheep breeds were all B(61.50%) and B(50.00%),and the dominant genotypes were BD(43.00%) and BB(27.27%). There were 4alleles detected, combined ten genotypes in exon11. The dominant alleles of the two sheep breeds were A(43.50%) and B(32.15%), and the dominant genotypes were all AB, the genotype frequencies were respectively 34.50% and 16.47%.(3)The two sheep breeds had rich polymorphism in the 3 detection regions ofthe HIF-2α gene, and there is highly significant difference in allele and genotype frequencies between two breeds(P<0.01). It is speculated that the HIF-2α gene may be selected in the process of adaptation to hypoxia at high altitude. Along with the long-term high altitude hypoxia environment, genotype individuals that are beneficial to adapt to high altitude hypoxia are positively selected in high altitude sheep breed,and the frequency is increased; genotype individuals that are not conducive to adapt to high altitude hypoxia are negatively selected in high altitude sheep breed, resulting in allele frequency decreased.(4) The highest homology between sheep and goat in the exon 8, 9 of the HIF-2α gene, and the distance of them in the phylogenetic relationships were concordant.In summary, there is all highly polymorphism in 3 detection regions of HIF-2αgene in sheep, and the breeding potential is greater. By analyzing the polymorphism of the HIF-2α gene in two sheep populations, it can provide basic datas for the study of the study of the candidate genes in the plateau hypoxia environment.