Study On The Variation Of EGLN1 And PPARA Genes And The Adaptability Of Plateau Hypoxia In Tibetan Sheep

EGLN1 and PPARA genes are the candidate genes for animals to adapt to high altitude hypoxia and mainly involved in hypoxia-inducible pathways.In order to explore the molecular mechanism of plateau hypoxia adaptation for Tibetan sheep,we used the EGLN1 and PPARA genes as the starting point for the reference to Hu sheep breeding at low altitude.PCR-SSCP and sequencing techniques were used to detect nucleotide variation in Tibetan sheep and Hu sheep populations in four different regions of EGLN1 gene and two different regions of PPARA gene,qRT-PCR was used to detect the relative expression of EGLN1 and PPARA genes in six different tissues of Tibetan sheep and Hu sheep.The main results of this study are as follows:1.The results of four amplified regions of EGLN1 gene in Tibetan sheep and Hu sheep:no mutation sites were detected in the third exon amplification region.One SNP was detected in the third intron amplification region.The dominant genotype of the two populations were both A₂A₂ and the dominant allele were A₂.Among them,the B₂B₂ genotype was not detected in the Hu sheep population.Two SNPs were detected in the amplification region of the sixth intron.The predominant genotype of Tibetan sheep was A₃B₃,the dominant genotype of Hu sheep was A₃A₃,and the dominant allele of two sheep populations was A₃.Five SNPs and one base insertion and one base deletion were detected in the fifth intron-sixth intron amplification region.The predominant genotype of Tibetan sheep was AB,the dominant allele was B,and the advantage genotype of Hu sheep was AA,the dominant allele was A,and the BD genotype was not detected in Hu sheep population.In the third intron and sixth intron amplification regions,both populations were moderately polymorphic?0.27<PIC<0.36?.But in the fifth intron-sixth intron amplification region,Tibetan sheep were highly polymorphic?PIC=0.63?and moderately polymorphic in Hu sheep?PIC=0.42?,indicating that Tibetan sheep have a high degree of genetic variation in the region and are more conducive to artificial selection.The frequency of the genes was statistically significant between the two groups?P<0.01?.It was speculated that the predominant genotypes of Tibetan sheep may be more suitable for adaptation to high altitude and hypoxia environment.2.The results of two amplification regions of PPARA gene in Tibetan sheep and Hu sheep:Two SNPs were detected in the third-fouth intron amplification region.The predominant genotype of Tibetan sheep was E₁F₁,and the predominant genotype of Hu sheep was E₁E₁,and the dominant alleles of both populations were E₁.Both populations in this region are moderately polymorphic,with PIC values of 0.36 and0.27,respectively,which have high genetic variation and are good for genetic selection.One SNP was detected in the fifth exon amplification region.the dominant genotypes of two sheep populations were E₂E₂,the dominant alleles were E₂,and genotype F₂F₂ was not detected in the Tibetan sheep population.In this amplified region,Tibetan sheep belonged to low polymorphism?PIC=0.06?and Hu sheep belonged to moderate polymorphism?PIC=0.31?.The genetic frequency of the two populations were statistically significant?P<0.01?.It was speculated that the predominant genotypes of Tibetan sheep may be more suitable for adaptation to high altitude and hypoxia environment.3.The mRNA expression levels of EGLN1 and PPARA genes were widely expressed in six tissues of Tibetan sheep and Hu sheep,and there were differences in expression.The mRNA expression of EGLN1 and PPARA genes in tissues of Tibetan sheep was lower than that of Hu sheep,especially in the heart,liver and lung tissues?P<0.01?.The results indicated that may be related to long-term adaptation to plateau hypoxia environment.In summary,by analyzing the polymorphism of EGLN1 and PPARA genes and tissue expression differences in Tibetan sheep.The partial alleles of EGLN1 and PPARA genes can be used as molecular markers for hypoxia adaptation in Tibetan sheep.