Genes and Brains Tell the Tale of Human Evolution Tuesday, March 13, 2007Posted by henry000 in Africa, anthropology, Australopithecus, evolution, genetics, homo erectus, homo sapien, human evolution, science, world.
This wonderful article titled “Beyond Stones & Bones” provides a great summary of recent discoveries to human evolution, in particular in the area of genetics and brain science.
The great tale of human evolution is just so fascinating. A vital part of it is the use of genetics to tell the story. A delightful example provided in this article is that of using body lice to infer when human lost their body hair for good. It goes like this: body lice live in cloths, so by the time they appeared, human would have started to cover themselves with some sort of clothing, which implies loss of body hair. Now body lice is evolved from head lice (which lives in our hair), so by comparing their DNA changes, which happens at regular rate, we could calculate when human started to lose body hair for good. Using this clever technique, scientists concluded that this happened about 114,000 years ago.
Using DNA scientists have worked out that humans and chimps evolved apart around 5 to 6 millions years ago, supported by the fact that the climate became dramatically colder around that time. The recent discoveries of the HAR1 and PDYN genes shred some light on how the brain plays its part in the evolution. The HAR1 gene may “… likely helped the cortexes of our ancestors develop the elaborate folds characteristic of a complex brain”, and that the PDYN gene may have advanced brain chemistry.