“Tibetans live at altitudes of 13,000 feet, breathing air that has 40 percent less oxygen than is available at sea level, yet suffer very little mountain sickness.
The reason, according to a team of biologists in China, is human evolution, in what may be the most recent and fastest instance detected so far. Comparing the genomes of Tibetans and Han Chinese, the majority ethnic group in China, the biologists found that at least 30 genes had undergone evolutionary change in the Tibetans as they adapted to life on the high plateau. Tibetans and Han Chinese split apart as recently as 3,000 years ago, say the biologists, a group at the Beijing Genomics Institute led by Xin Yi and Jian Wang. The report appears in Friday’s issue of Science.
If confirmed, this would be the most recent known example of human evolutionary change. Until now, the most recent such change was the spread of lactose tolerance — the ability to digest milk in adulthood — among northern Europeans about 7,500 years ago. But archaeologists say that the Tibetan plateau was inhabited much earlier than 3,000 years ago and that the geneticists’ date is incorrect.
When lowlanders try to live at high altitudes, their blood thickens as the body tries to counteract the low oxygen levels by churning out more red blood cells. This overproduction of red blood cells leads to chronic mountain sickness and to lesser fertility — Han Chinese living in Tibet have three times the infant mortality of Tibetans.
The Beijing team analyzed the 3 percent of the human genome in which known genes lie in 50 Tibetans from two villages at an altitude of 14,000 feet and in 40 Han Chinese from Beijing, which is 160 feet above sea level. Many genes exist in a population in alternative versions. The biologists found about 30 genes in which a version rare among the Han had become common among the Tibetans. The most striking instance was a version of a gene possessed by 9 percent of Han but 87 percent of Tibetans.”
Read more at NYTimes (Thanks DG)
Hm, I wonder whether those tibetan people would start to suffer from sea altitude sickness if they need to live there for a while?
And what if you would raise a non tibetan child up there .. wouldn’t it adapt just as easy even though it would not have these altered genes. Can genes alter during life itself so not only over generations. I myself would not find that so weird.
Are the red blood cells enlarged of the Tibetans instead of higher in number? I myself we can trigger a simular state in our body, although we mostly wont trigger that from full conscious. Tibetan’s/chinese already have a different body systems than us e.g., we seem to be different attached to our bases, more direct. As if we should not be on top of all our body systems to cope with the climate. Can be seen in eyes.
If we combine this info with the recently discovered ‘fact’ that life experiences seem to affect the genes in sperm and therefore offspring, we have a model of evolution that is facilitated not just by random mutations but by active adaptation to an environment.
Survival of the fittest + children with rapid adaptations = evolution and survival of the population.
Wow, wow, wow.
well, it makes sense. but…we are devo.
Yeah, granted it is a change from the regular human being, but it isn’t much of a change really. Usually people accosiate the word ‘evolution’ with something like monkeys turning into humans or a fish growing another limb, but not just a few changes in some genes…
iHD: Well, maybe those people should look up what evolution is, then, because they are apparently associating it with events that don’t happen outside of comic books. Monkeys never turned into humans — some of an ape-like creature’s offspring slowly adapted to a different environment and eventually, over the course of millennia, became our species. Fish never grew limbs, but some fish developed pectoral fins that they could walk with, and over many generations the fish became amphibian and the fins became limb-like. That’s how evolution works — by a lot of little steps, not by magical giant leaps.
apparently evolution is speeding up and a study showed that humans 2000 years ago were more similar to neanderthals than to us. Also orangutans have recently been seen hunting and fishing with sticks!
Scott: I find that highly unlikely, as neanderthals were a seperate species and there was relatively little interbreeding between them and H. sapiens. Also, I don’t recall any Greek or Roman statues with eyebrow ridges.
@Scott – Genetically, im afraid we are just as close to the Romans as we have always been… and def. much closer than they are with neanderthals… thats not to say we are that different though. There is a major debate surrounding the speciation of neanderthals from humans, which i cant really fit here…
but as berber anna points out… evolution doesn’t work overnight… its loads of small adaptive changes, mutations that might give an individual a slight edge over others – that drives changes in future generations. we are constantly evolving, we never stopped! it is even thought that the reason for the neanderthal extinction is that they weren’t able to adapt THAT quickly to a faster changing environment and therefore could not sustain a reproductively viable population
Evolution can be very fast. I wonder if being at higher altitudes exposed them to more DNA altering radiation?