If one little baby ape, a long long time ago, had an especially helpful mutation, how long would it take before all apes inherited that single genetic improvement? Biologist Christopher Rupe (colleague of last week's guest, geneticist John Sanford) helps Real Science Radio get a better understanding of the science of population genetics. Bob Enyart asks Rupe about something called genetic fixation, about alleles, and the percentage of mutations that are beneficial. The discussion also asks, with the distribution of helpful mutations being exceedingly slower than a snail's pace, what is the pace of the accumulation of harmful mutations? Listeners will also learn about the test of the ape-to-man hypothesis, about how dissimilar chimp DNA is from the human genome, and why the Y chromosome should be the most similar but it is so wildly different that it's as close to a chick Y as a chimp Y! See also Mendel's Accountant, the web's software tool to simulate the theory of evolution. (Finally, we're working on getting a video of Rupe's college lecture so we can embed it on this page. And in the meantime, here's Chris' colleague's lecture at NIH: