A new genetic analysis shows that Tibetans’ EPAS1 gene has undergone the most rapid genetic change out of all human genes, according to an analysis conducted by researchers in China, Europe, and the United States. The team chalks the change up to Tibet’s high altitude.
Researchers discovered a handful of genetic mutations that were more common in the Tibetans.
When a human—living in low or moderate altitudes—heads to high altitudes, his body adjusts to the thin air by producing more red blood cells and hemoglobin. While this increased production compensates for the drastically decreased amount of oxygen, there’s a cost: chronic altitude sickness, headaches, and increased exhaustion. Unlike most humans, however, Tibetans are able to endure the thin air of high altitudes without increased red blood cell and hemoglobin production.
Relying on genomic data from 50 unrelated Tibetans, 40 Chinese, and 200 Danes, researchers discovered a handful of genetic mutations that were more common in the Tibetans. Many control how the body uses oxygen. The starkest genetic difference came in the form of an EPAS1 allele (a sort of “version” of a particular gene). The allele showed up in eighty-seven percent of Tibetans, compared to only nine percent of Chinese and nearly none of the Danes.
Based on the analysis, the researchers conclude Tibetans diverged from the main Chinese group about 2,750 years ago, which would make the EPAS1 mutation the most recent example of human evolution compared to other evolutionary estimates. But as with mice adapted for living in high altitudes (see item ), Tibetans’ adaptation for life in thin air can be understood within the framework of natural selection, which is fully compatible with young-earth creation. Given a distribution of EPAS1 alleles in an earlier population, those with the mutation for high-altitude living survive and reproduce more successfully than others in the plateaus of Tibet; eventually, the population overwhelmingly includes the high-altitude EPAS1 allele. Additionally, if the high-altitude EPAS1 allele results in some deficiency elsewhere in the body—and is therefore costly to have except in high altitudes—this explains why relatively few non-Tibetan Chinese, and virtually no Danes, carry the high-altitude allele. Natural selection, not molecules-to-man evolution, explains the change.
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