Hypoxia adaptations in the grey wolf (Canis lupus chanco) from Qinghai-Tibet Plateau

PLoS Genet. 2014 Jul 31;10(7):e1004466. doi: 10.1371/journal.pgen.1004466. eCollection 2014 Jul.

Abstract

The Tibetan grey wolf (Canis lupus chanco) occupies habitats on the Qinghai-Tibet Plateau, a high altitude (>3000 m) environment where low oxygen tension exerts unique selection pressure on individuals to adapt to hypoxic conditions. To identify genes involved in hypoxia adaptation, we generated complete genome sequences of nine Chinese wolves from high and low altitude populations at an average coverage of 25× coverage. We found that, beginning about 55,000 years ago, the highland Tibetan grey wolf suffered a more substantial population decline than lowland wolves. Positively selected hypoxia-related genes in highland wolves are enriched in the HIF signaling pathway (P = 1.57E-6), ATP binding (P = 5.62E-5), and response to an oxygen-containing compound (P≤5.30E-4). Of these positively selected hypoxia-related genes, three genes (EPAS1, ANGPT1, and RYR2) had at least one specific fixed non-synonymous SNP in highland wolves based on the nine genome data. Our re-sequencing studies on a large panel of individuals showed a frequency difference greater than 58% between highland and lowland wolves for these specific fixed non-synonymous SNPs and a high degree of LD surrounding the three genes, which imply strong selection. Past studies have shown that EPAS1 and ANGPT1 are important in the response to hypoxic stress, and RYR2 is involved in heart function. These three genes also exhibited significant signals of natural selection in high altitude human populations, which suggest similar evolutionary constraints on natural selection in wolves and humans of the Qinghai-Tibet Plateau.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acclimatization / genetics
  • Adaptation, Physiological / genetics*
  • Altitude
  • Animals
  • Genetics, Population
  • Humans
  • Hypoxia / genetics*
  • Oxygen Consumption / genetics
  • Polymorphism, Single Nucleotide
  • Selection, Genetic / genetics*
  • Tibet
  • Wolves / genetics*

Grants and funding

The project was supported by the Chengdu giant panda breeding research foundation (CPF-yan-2012-10), Chengdu research base of giant panda breeding, the State Scholarship Fund of China Scholarship Council, the National Key Technology R&D Program (2012BAC01B06), and National Science Foundation grant DEB-1021397 to RKW. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.