We live at high altitude here in Ecuador and are accustomed to going over 4,000 metres when we visit the sierra or even drive over the Eastern cordillera on our way to the Amazon jungle. Our bodies can become acclimatised to the thin air after a few weeks and months. The long-term inhabitants of the sierra of the Andes have physiological and anatomical adaptations that enable them to survive happily at these extreme altitudes, where air pressure can be a third lower than at sea level, thus making it so hard to obtain the oxygen they require. The phenotypic adaptations are the result of a small number of genetic differences between the people of the sierra and those who live lower.
Interestingly the people of the Tibetan Plateau, also living well above 4,000 metres, show significantly different physiological, anatomical and genotypic differences to their compatriots lower down the mountains. That raises interesting questions and takes us into the realm of human ancestry and evolution. The BBC article linked here describes research which suggests that the people of the Tibetan Plateau have unique genes which demonstrate origins, some 50-30,000 years ago, from early human ancestors called the Denisovans. Foot and hand prints found on the Tibetan Plateau a long time ago have always puzzled scientists and the general acceptance was that they were evidence of human occupation which coincided with the advent of an agricultural economy 5,000 to 3,000 years ago. It can now be proposed that early habitation of the high Tibetan Plateau began long before an agricultural economy appeared.
This research has been possible by the ease with which geneticists can now look at genomes and just shows how major improvements in scientific techniques help propel significant advances in knowledge and understanding. This is a repeating Nature of Science theme in the new IB syllabus in Biology.