Most people are aware that altitude imposes constraints on individual performance and function. Much of this is flexible; athletes who train at high altitudes may gain a performance edge. But over the long term there are costs, just as there are with computers which are ‘overclocked.’ This is the point where you make the transition from physiology to evolution. Residence at high altitude entails strong selective pressures on populations. Over the past few years there has been a great deal of exploration of the genetics of long resident high altitude groups, the Tibetans,Peruvians, and Ethiopians.
Why is high altitude adaptation of interest? First, it’s clear and distinct. Coding the two phenotypes is not that difficult. Second, the adaptive value is clear. Though people can survive at high altitudes, most do not flourish. And third, you have several distinct populations which are phylogenetically diverse. In other words, you can test evolution across multiple lineages, and see if the phenotypic and genetic features resemble each other, or differ. To some extent we know the answer: though there are overlaps, altitude adaptations differ both in their physiological presentation, and in their genetic architecture. Because it is such a powerful force, the shape of adaptation to high altitudes gives us a better sense of the arc of evolution across diverse populations and times.
View the original article here: We don’t know why Ethiopians breathe easy