tag:blogger.com,1999:blog-7785493.post2317634530322718531..comments2024-01-04T04:11:55.717+02:00Comments on Dienekes’ Anthropology Blog: The long, drawn-out road to usDienekeshttp://www.blogger.com/profile/02082684850093948970noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-7785493.post-78333525733200747312012-08-01T05:35:53.018+03:002012-08-01T05:35:53.018+03:00"One of the major problems with genetic time ..."One of the major problems with genetic time estimates currently is that we estimate three of the unknowns to solve the fourth". <br /><br />But it is very interesting to play with the figures even though we can be certain that they are wrong. <br /><br />"Perhaps the most destructive assumption in genetics is a stable population size, many algorithms depend on that, and if you look at recent human history, that is anything but true". <br /><br />Yes, but just as destructive is an assumption of steady increase in population. Like most species our numbers have almost certainly fluctuated wildly.terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-16534798595858656152012-07-31T06:16:10.357+03:002012-07-31T06:16:10.357+03:00Unknowns:
1) Divergence Time
2) Mutation Rate
3) ...Unknowns:<br /><br />1) Divergence Time<br />2) Mutation Rate<br />3) Population Size<br />4) Population Growth Rate<br /><br />and many other unknowns.<br /><br />I learned early on that to solve for 4 unknowns you need 4 equations.<br /><br />One of the major problems with genetic time estimates currently is that we estimate three of the unknowns to solve the fourth.<br /><br />We don't have a crystal ball that can look back into the past to know for certain the values of the other unknowns, and often we are very wrong.<br /><br />Perhaps the most destructive assumption in genetics is a stable population size, many algorithms depend on that, and if you look at recent human history, that is anything but true.Aaronhttps://www.blogger.com/profile/01270554253475715322noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-71846146680627524522012-07-27T05:58:12.005+03:002012-07-27T05:58:12.005+03:00"The H. Li, R. Durbin paper cited by Weaver i..."The H. Li, R. Durbin paper cited by Weaver is fascinating - I don't think I paid attention to it, previously" <br /><br />You're right. <br /><br />"All three populations have an elevated effective population size between 60 and 250 kyr ago, possibly due to population substructure. We also infer that the differentiation of genetically modern humans may have started as early as 100–120 kyr ago12, but considerable genetic exchanges may still have occurred until 20–40 kyr ago". <br /><br />That again argues against the simple, 60 kya. OoA.terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-73346814243198477352012-07-26T15:07:47.310+03:002012-07-26T15:07:47.310+03:00Great argumentGreat argumentRobhttps://www.blogger.com/profile/07166839601638241857noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-44072682418236161022012-07-26T13:44:48.904+03:002012-07-26T13:44:48.904+03:00The H. Li, R. Durbin paper cited by Weaver is fasc...The <i>H. Li, R. Durbin</i> paper cited by Weaver is fascinating - I don't think I paid attention to it, previously:<br /><br />http://www.nature.com/nature/journal/v475/n7357/full/nature10231.html<br /><br />* their calculation results in a population maximum coinciding with the climatic optimum ~150 - 100 kyr ago;<br /><br />* differentiation of European and Asians from Youruba started 120–100 kyr ago (!)eurologisthttps://www.blogger.com/profile/03440019181278830033noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-76430112937271774242012-07-26T05:34:59.728+03:002012-07-26T05:34:59.728+03:00"Overall, I would say that Weaver makes a goo..."Overall, I would say that Weaver makes a good argument against the idea of us being something special in the grand scheme of things. Perhaps we're not mutant world conquerors after all, but rather the latest phase in a long and drawn-out evolution of Homo. It's a less dramatic and more mellow theory about our origins, but one that may very well be true". <br /><br />Almost certainly is true. <br /><br />"modern human origins could have been a lengthy process that lasted from the divergence of the modern human and Neandertal evolutionary lineages to the expansion of modern humans out of Africa, and nothing out of the ordinary happened 200,000–100,000 years ago in Africa". <br /><br />I have long been very suspicious of any alternative theory. <br /><br />"He proposes that there was no punctuational "rise of modern humans", but rather a long, drawn-out continuous process since our split with our closest cousins, the Neandertals". <br /><br />I'd take it even further back, from the time of Homo erectus. And most likely long before that time.terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.com