XI’AN – Surviving at a harsh 5,000meter-altitude is almost impossible for the majority of living organisms, but not for Himalayan marmots.
This encouraged biologists from Xi’an Jiaotong University in China to sequence the first complete Himalayan marmot genome, to help them better explain how the marmots live in such extremes, Science Daily reported on December 20.
“As one of the highest-altitude-dwelling mammals, the Himalayan marmot is chronically exposed to cold temperature, hypoxia, and intense UV radiation,” said Enqi Liu of the university’s Health Science Center.
The findings, which appeared in the journal iScience, hint at the genetic mechanisms underlying high-altitude adaptation and hibernation. They also serve as a valuable resource for researchers studying evolution, highland disease, and cold adaptation.
Striking biological features of Himalayan marmots like hibernating for more than six months during the wintertime led the research team to study the molecular mechanisms of adaptation to extreme environments.
They sequenced and assembled a complete draft genome of a male Himalayan marmot. They also re-sequenced 20 other Himalayan marmots, including individuals living at high and low altitudes, and four other marmot species.
Then, the researchers managed to sequence the marmot RNA as well to compare gene-expression differences between marmots in a state of torpor and awake marmots.
Key to Survival
Allah Almighty says in the Holy Qur’an: {Behold! in the creation of the heavens and the earth, and the alternation of night and day,- there are indeed Signs for men of understanding,-} (Surat Ali ‘Imran 3: 190).
The Chinese team of geneticists identified two genes, Slc25a14 and Aamp (a processed pseudogene), that have been selected in different directions in marmots living at low versus high altitudes, suggesting they are related to survival in high-altitude populations under conditions of extremely low oxygen.
They suggest that Slc25a14 may have an important neuroprotective role. The shift in Aamp affects the stability of RNA encoding the gene Aamp, which may be a protective strategy to prevent the excess growth of new blood vessels under extremely low-oxygen conditions.
The RNA sequencing data show that gene-expression changes occur in the liver and brain during hibernation. These include genes in the fatty acid metabolism pathway as well as blood clotting and stem cell differentiation.