VEGF-A loci plausibly associated with high altitude adaptation in yak is completely fixed in cattle population from high and low altitude environments

Abstract

Vascular endothelial growth factor-Alpha (VEGF-A) is essential for the growth of new blood vessels promoting angiogenesis and plays an important role in high altitude adaptation. In the present study, an effort was made to undertake comparative screening of SNPs at two specific positions in VEGF-A gene (g.8430T C and g.14853GA) in high altitude adapted Ladakhi cattle, cross bred maintained at high altitude, tropically adapted native cattle breeds and yak. The PCR amplified product of corresponding region harbouring the two SNPs was investigated by PCR-RFLP approach to ascertain the allelic/genotypic distribution of VEGF-A variants across Indian cattle and yak. PCR- RFLP was performed in a total of 337 animals comprising 6 native cattle breeds, 1 cattle population from high altitude and 1 population of yak from north-eastern part of India. In addition, 60 samples of yak and native cattle were sequenced to detect any additional variation in the amplified region of VEGF gene. In yak, the genotyping at locus g.8430TC revealed three genotypes viz. CC (245bp), CT (245+215bp) and TT (215bp) while at locus g.14853GA, the genotypes identified were; GG (241bp), GA (241+143+98 bp) and AA (143+98 bp). Interestingly, in cattle breeds, at both these positions, only homozygous genotype (CC and GG respectively) was observed. Overall, the data showed complete fixation of C allele; CC genotype at locus g.8430TC and G allele, GG genotype at locus g.14853GA of VEGF-A gene in cattle breeds from both high and low altitude environments. Thus, the result of the present study indicated that both these loci of VEGF-A gene are not associated with high altitude adaptation trait of cattle population from Leh and Ladakh region of India.