Geneticists meet to work out why the rate of change in the genome is so hard to pin down.
Wouldn’t that have some effect on the believability of time scales for human evolution?:
A slower molecular clock worked well to harmonize genetic and archaeological estimates for dates of key events in human evolution, such as migrations out of Africa and around the rest of the world1. But calculations using the slow clock gave nonsensical results when extended further back in time — positing, for example, that the most recent common ancestor of apes and monkeys could have encountered dinosaurs. Reluctant to abandon the older numbers completely, many researchers have started hedging their bets in papers, presenting multiple dates for evolutionary events depending on whether mutation is assumed to be fast, slow or somewhere in between.
Last year, population geneticist David Reich of Harvard Medical School in Boston, Massachusetts, and his colleagues compared the genome of a 45,000-year-old human from Siberia with genomes of modern humans and came up with the lower mutation rate. Yet just before the Leipzig meeting, which Reich co-organized with Kay Prüfer of the Max Planck Institute for Evolutionary Anthropology, his team published a preprint article that calculated an intermediate mutation rate by looking at differences between paired stretches of chromosomes in modern individuals (which, like two separate individuals’ DNA, must ultimately trace back to a common ancestor). Reich is at a loss to explain the discrepancy. “The fact that the clock is so uncertain is very problematic for us,” he says. “It means that the dates we get out of genetics are really quite embarrassingly bad and uncertain.” More.
Just what they need when launching a war on Those Who Doubt “Science.”
See also: Conundrums of human evolution