If those genes don't work, babies are born with severely small brains, called microcephaly.Using DNA samples from ethnically diverse populations, they identified a collection of variations in each gene that occurred with unusually high frequency.:) Welcome to one of the fastest growing Italian singles sites on the web.
Start a live conversation and see someones beautiful smile!
Years later, a ruler declares one of those copies the definitive manuscript, and a rush is on to make many copies of that version — so whatever changes from the original are in this presumed important copy become widely disseminated.
Scientists attempt to date genetic changes by tracing back to such spread, using a statistical model that assumes genes have a certain mutation rate over time.
For the microcephalin gene, the variation arose about 37,000 years ago, about the time period when art, music and tool-making were emerging, Lahn said.
For ASPM, the variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said.