Mar 2006 - Human genes involved in metabolism, skin pigmentation, brain function and reproduction have evolved in response to recent environmental changes, according to a new study of natural selection in the human genome. Researchers at the University of Chicago, US, developed a statistical test to find genomic regions that evolution has favoured over the last 15,000 years or so â when modern humans dealt with the end of the last ice age, the beginning of agriculture, and increased population densities. Many of the 700 genes the researchers identified â especially those involved in smelling, fertility, and reproduction â are also suspected of having undergone natural selection during the divergence of humans and chimpanzees millions of years ago. But some of the newly identified genes fall into categories not previously known to be targets of selection in the human lineage, such as those involved in metabolism of carbohydrates and fatty acids. Milk lovers âItâs reasonable to suspect that a lot of these are adaptations in response to new diets and agriculture,â says team member Jonathan Pritchard. For example, gene variants that improve the digestion of lactose have become more common, presumably since the domestication of cattle provided a ready source of milk. And in some Europeans, genes giving a lighter skin have increased in frequency, as populations have moved north to regions where there is less sunlight to generate vitamin D. The researchers analysed the genomes of 209 people from Nigeria, East Asia, and Europe. They found widespread signals of recent selection in all three populations. Only one-fifth of the 700 genetic regions identified were shared between at least two of the groups â the rest were unique to single populations. That supports the idea that the adaptations are recent, Pritchard explains.
fuck off you lot. youre just all jealous cos youre all a bunch of cross breeds & mongrels, not like my lovely uncontaminated arian blood line. me pedigree. you mongrel. end of. now go back to dorking yer mom & sisters.
Romans preferred dark hair; but they did like burning the villages of fair-haired Celts. Had Romans preferred blond hair, there would probably be fewer blondes today. For example, had all Roman legionaires raped all Celt women from every captured Celt village, there would necessarily have been fewer offspring of both fair-haired Celt males and fair-haired Celt females. To illustrate: when a dark-haired male and a fair-haired female mate, the offspring is less likelly to be fair-haired. Thus, the multitude of the fair-haired today proves Romans--as just one example as one could also include Huns/Mongols and Turks--found fair-hair less desirable than dark hair. Quod erat demonstrandum.