3 tweets By David Winter • 20/05/2011 • 4 This post was syndicated from The Atavism - View original source Let’s see if Storify stories can be embedded in blogger (if not, I guess you’ll have to read it here) evolution genetics sci-blogs science communication speciation species Twitter 4 Responses to “3 tweets” “That’s natural selection, but even without selection, change happens” you need to couch your terms with more precision here. genetics of a population can not change without selection of some type. call it natural, self- or unnatural selection, it still results in a change to the population genetic composition. you also need to differentiate epi-genetic, somatic and gamete based ‘population’ genetics. “new genes” may not be “made” but rather recombined into new configurations (transcription error) rather than displaying as a SNP. Bob, As you might imainge it’s hard getting details into 420 characters, but I respectfully disagree with your points ;). genetics of a population can not change without selection of some type They can and do. All populations are finite, so in every generation you sample the last generations gene pool complete with sampling error. That means populations always change, and small ones fluctuate more wildly than large ones. Because mutation, and other forces, are always delivering new genes to populations, each with a small chance of becoming fixed, new genes will eventually become fixed. Kele Cable has an interesting post about whether we should consider drift the background against which all other forces play out. â€œnew genesâ€ may not be â€œmadeâ€ but rather … Aren’t all those just different ways of ‘making’ genes? Have to say your explanations were easier to understand than Sean Carrol’s. I only followed them because I had previously read Brian Green’s “The Elegant Universe”. Yours require much less background info, or perhaps more of the background is widely understood. I think I sort of chose easier topics too. Like, I wanted to explain something controversial like “can species arise without geographical isolation” then I’d really need the species/speciation tweets before I could start talking about how/why that might not work. Whereas Carroll jumped right in at M-Theory!