Mitochondrial Genes Reveal The Plateau Adaptability Of Wolves

High-altitude adaptation refers to huamn and animals inhabit on plateau arise irreversible and heritable changes of morphological, physiological and biochemical aspects in order to adapt to the high altitude hypoxia, extremely cold environment, thus they can survive and breed well in the high-altitude environment. Qinghai-Tibetan Plateau is the highest and largest high-altitude ecosystems in the world, because of its geographical isolation, animals living on the Qinghai-Tibet Plateau have had a better adaption to the harsh plateau environment,such as low temperature, low oxygen, strong ultraviolet radiation, and produced a stable, heritable variation.Mitochondrion provides energy for animals’ vital movements and generate heat to maintain body temperature. Due to the particularity function of mitochondrion, natural selection plays an important role in mitochondrial genome’s evolution. Research by Luo Y et al.(2008) on Ochotona Curzoniae’s mitochondrial genome found fifteen novel mitochondrial DNA-encoded amino acid changes in Ochotona Curzoniae, including three in the subunits of cytochrome c oxidase.These amino acid substitutions potentially function in modulation of mitochondrial complexes and electron transport efficiency during cold and hypoxia adaptation.Therefore, we analysis mitochondrial genes in order to reveal high-altitude adaptation of Chinese wolf.Canis lupus which is generally called gray wolf, is the largest canidae in the world. Because of its strong adaptability, Canis lupus once widely distributed in north of latitude 20° Eurasia and most areas of the North American continent except the tropical rainforest and desert(Mech, 1974).In China, in recent years, due to the serious damage of the habitat and human’s hunting, distribution area of Canis lupus are being greatly reduced,and the population declined extremely.Due to the special high-altitude environment of Qinghai-Tibetan Plateau and repeated glacial activity in history, Canis lupus inhabit on plateau has a very complex evolutionary history. Our research analysised the genetic diversity、genetic distance and phylogenetic relationship within different geographical groups of Chinese Canis lupus based on mitochondrial DNA Control region sequence. We compared the difference of selective pressures that high-altitude groups and low-altitude groups based on mitochondrial ATPase gene and COX gene, in order to reveal the differences and find Genetic evidence of high-altitude adaptation of Canis lupus.The results reveal that, Compared with other populations of the world, Chinese wolf has higher rate of genetic diversity and more abundance of genetic resources. However, The rates of genetic diversity within some geographical groups are low,which might bring negative affect on breeding and evolution. Phylogenetic analysis showed that there are significant genetic differentiations between populations at low-altitude and high-altitude. Evolutionary divergence time within groups is consistant to the time of the formation of Qinghai-Tibetan Plateau and highland climate, so we suggest that climate changing and geographic isolation mainly caused the genetic differentiation of Chinese wolf.By analysing selection pressure on Chinese wolf,we found a number of positively selected sites and negatively selected sites,of those variations may be associated with energy metabolism.High-altitude adaptation of Canis lupus is very complex,not only because of climate changing and geographic isolation. Our research found ample evidence of high-altitude adaptive evolution of canis lupus. In future research, we will collect more samples of Canis lupus,and use more powerful methods to analysis the influence of climate change on the evolution of Canis lupus, and reveal the molecular mechanism of evolution.We devote to propose feasible countermeasures for Canis lupus’ management and protection.