Scientists from the Kunming Institute of Zoology announced on July 3 they have completed the genomic sequence of a female domestic yak (Bos grunniens). The goal of their research was to tease out genetic variations that enable some mammals to adapt to high-altitude living.
The scientists were working alongside colleagues from 16 different international research laboratories in order to reach their goal.
The first organism to have its genetic code sequenced was the Haemophilus influenzae bacterium in 1995. Since then more than 190 plant, animal and microorganism species, including humans, have had their DNA mapped.
Yaks were chosen because they are very closely related to domesticated cows that live at lower altitudes, allowing scientists to compare genetic differences between the two with relative ease.
The two species are as closely related genetically as humans are to chimpanzees. Yaks and cattle also diverged around the same time humans and chimpanzees did, approximately 4.9 million years ago.
Research conducted after Yak DNA was sequenced revealed the animal has specific genetic variations that allow it to grow to a size high altitude air usually does not allow.
Three genes specifically affect the way a yak's body processes thin air that lacks oxygen and commonly leads to hypoxia in other animals. Most mammals have an automatic reaction to low oxygen levels wherein blood vessels in their lungs constrict. Yaks do not have this reaction.
A separate set of five genes enables yaks to obtain maximum nutrition from scarce forage while optimizing energy metabolism. This enables them to grow much larger than similar animals could from the same diet.
The sequencing may lead to a broader understanding of how all mammals react to high altitude conditions. According to Esciencenews:
Researchers explained that the study on high-altitude adaptation may help to improve current understanding, treatment, and prevention of altitude sickness and other hypoxia-related diseases in humans.
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