Analysis of two sequence variants in peroxisome proliferator-activated receptor gamma gene in a Tibetan population at high altitude and a Han population at low altitude in China.

Background: The Tibetan people in China have lived at high altitude for thousands of years, raising the possibility that the Tibetans are genetically adapted to high altitude. In this study we analyzed the Pro12Ala (C>G) polymorphism in exon 2 and the 161C>T polymorphism in exon 6 of peroxisome proliferator-activated receptor gamma gene (PPARγ) in a Tibetan population and a Han population.

Material/methods: We recruited 142 Tibetan volunteers who are permanent inhabitants in Qingzang plateau (higher elevation) and 266 Han volunteers who are permanent inhabitants in the plain (lower elevation). PCR/RFLP method was applied to examine the 2 polymorphisms in the 2 populations.

Results: Significantly higher Pro12Ala (C>G) CC genotype frequency and 161C>T CC genotype frequency were observed in the Tibetan population compared to the Han population (p<0.001). When the samples were stratified by sex, significant differences were only observed in females. The haplotypes constructed by Pro12Ala (C>G) and 161C>T were also analyzed. The frequency of the haplotype CC (p<0.0001) was significantly higher, while the frequency of the haplotype CT (p<0.0001) and GT (p<0.01) was significantly lower in the Tibetan population than in the Han population.

Conclusions: Our results suggested that PPARγ might be a candidate gene for high-altitude adaptation; the Pro12Ala (C>G) CC genotype and/or the 161C>T CC genotype are possibly advantageous factors in the female Tibetan population. Alternatively, the difference of the Pro12Ala (C>G) genotype distribution and /or the difference of the 161C>T genotype distribution in the 2 populations may be due to the racial difference.