Study On Genetic Polymorphisms Of Four Hypoxia Adaptation Genes In Yak

Yak is a unique species of the Qinghai-Tibet Plateau.It survived at an altitude of 3,000 meters above the region,enjoy the “Plateau boat” praise.The yak has a strong adaptability to the ecological environment of the Qinghai-Tibet Plateau.The Shenzha yak,Pali yak,Leiwuqi yak,Sibu yak,Maiwa yak,Zhongdian yak and the Sanjiang cattle(reference cattle)were selected as the research object in this experiment.We selected the EPAS1?EGLN1?HOU1and HMBS genes as candidate genes and the DNA hybrid pool technique was used to combine the PCR-RFLP and direct sequencing,we also analyzed these four genes genetic polymorphisms of SNPs in yak.The molecular beacons of yak adapted to the plateau hypoxic environment were screened,so as to provide theoretical help for further study on the mechanism of hypoxia adaptation of yak.Get the following results:1.Three specific mutations(rs82125C?T?rs82138G?A and rs82140 A?C)were detected in the EPAS1 gene of yak.This three mutations were not detected in the Sanjiang cattle group.By genotyping,the CC genotype was dominant genotype in the Sibu yak and Zhongdian yak at the rs82125(C?T)mutation site,the heterozygous genotype TC was the dominant genotype in Shenzha yak,Pali yak,Leiwuqi yak and Maiwa yak;the GG genotypes were dominant in six yak populations at the rs82138(G?A)mutation sites;in addition to Zhongdian yak,the genotype AA were dominance genotype in the rest yak populations at the rs82140(A?C)locus.The chi-square suitability test showed that the Pali yak and Sibu yak were in an imbalance at the rs82125(C?T)locus;all other yak populations were in the Hardy-Weinberg equilibrium state.The haplotype Pearson's P value comparison analysis showed that the frequency of haplotype TGA in each yak group were significantly higher than that in other haploypes except for the low-altitude yak group(Zhongdian yak)and there is a very significant difference between the Pali yak and other yak groups.The haplotye TGA yak could be mare adaptation to the hypoxic environment of the plateau.The mutation of C?T in rs82125 could plays an important role in the process of yak adapting to the hypoxic environment of plateau.2.Two specific mutations(rs2900G?A and rs3386G?A)were detected in the EGLN1 gene of yak.This two mutations were not detected in the Sanjiang cattle group.By genotyping,the GG genotype was dominant genotype in the six yak groups at the rs2900(G?A)mutation site;the heterozygous genotype AG was dominant genotype in the Pali yak and Zhongdian yak and other yak groups were dominated by GG genotype at he rs3386(G?A)mutant locus.The chi-square suitability test showed that all yak groups were in the Hardy-Weinberg equilibrium state at the rs2900(G?A)locus and the Shenzha yak was in an unbalanced state at the rs3386(G?A)locus.The haplotype analysis showed that the frequency of haplotye GG in each yak group was significantly higher than that of other haplotypes.The haplotype GG yak may be more adaptating to the hypoxic environment of the plateau.The EGLN1 gene can be used as a molecular beacon for yak to adapt to the hypoxic environment of the plateau.3.Two specific mutations(rs19683C?T and rs20759G?A)were detected in the HYOU1 gene of yak.This two mutations were not detected in the Sanjiang cattle group.By genotyping,the heterozygous genotype TC was the dominant genotype in the Shenzha yak,Pali yak and Leiwuqi yak at the rs19683(C?T)mutation site,and the other yak groups were dominated by the CC genotype;In addition to the heterozygous genotype AG was the dominant genotype of the Shenzha yak,the genotype GG were dominant genotype in other yak groups at the rs20759(G?A)mutation site.The chi-square suitability test showed that all yak groups were in Hardy-Weinberg equilibrium state at the rs19683(C?T)and rs20759(G?A)locus.The haplotype analysis showed that the frequencies of haplotype CG were significantly higher than other haplotypes in Shenzha yak,Leiwuqi yak,Sibu yak,Maiwa yak and Zhongdian yak;the frequency of haplotype TG in Pali yak was significantly higher than other haplotypes.Pearson's P value comparison showed that there was a significant difference or very significant difference between at the high elevation of the Shenzha yak,Pali yak and Leiwuqi yak and the lower elevation of the Sibu yak,Maiwa yak and Zhongdian yak.Therefore,the haplotype CG yak may be more adapting to the hypoxic environment of plateau and rs19683 site C?T mutation to producing the advantages of haplotype TG may be more conducive to higher Pali yak to adapt to the long-term plateau hpoxic environment.4.Three specific mutatios(rs4161T?C?rs5819T?C and rs6068A?G)were detected in the HMBS gene of yak.This three mutations were not detected in the Sanjiang cattle group.By genotyping,we found there were significant differences or very significant differences between the high altitude of the Shenzha yak,Pali yak and Leiwuqi yak and the lower altitude of the Sibu yak,Maiwa yak and Zhongdian yak at the rs4161(T?C)locus.This results suggested that mutation in T?C may be beneficial to the adaptation of yak to the plateau hypoxic environment.The chi-square suitability test showed that the Leiwuqi yak was in an unbalanced state at the rs4161(T?C)locus;the Leiwuqi yak and Sibu yak were in an unbalanced state at the rs5819(T?C)locus;the Leiwuqu yak and Sibu yak were still in an unbalanced state at the rs6068(A?G)locus.The haplotpe analysis showed that the frequency of haplotype TTA was very significantly higher than other haplotypes in the Leiwuqi yak,Sibu yak and Maiwa yak and the frequency of haplotype CTA was significantly higher than other haplotypes in Shenzha yak and Pali yak.Pearson's P value comparison showed that P value had a very significant difference between the high altitude of the Shenzha yak and Pali yak and the lower elevation of the Sibu yak,Maiwa yak and Zhongdian yak.Therefore,the haplotype TTA yak may be more adapting to the hypoxic environment of plateau and the rs4161 site T?C mutation to producing the advantages of haplotype CTA may be more conducive to high altitude Shenzha yak and Pali yak to adapt to long-term plateau hypoxia.It is also speculated that the haplotype TCG of rs5819 site T?C and rs6068 site A?G mutation is not conducive to the better adaptation of yak to the plateau hypoxic environment.