tag:blogger.com,1999:blog-19346366.post116458866962551605..comments2024-03-27T23:28:20.274-04:00Comments on Face to Face: Interracial beauty is due to greater symmetry?agnostichttp://www.blogger.com/profile/12967177967469961883noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-19346366.post-1165295178052266942006-12-05T00:06:00.000-05:002006-12-05T00:06:00.000-05:00I'm pretty sure lactose tolerance is dominantthe e...<I>I'm pretty sure lactose tolerance is dominant</I><BR/><BR/>the european SNP which confers elevated transcription at a particular site on LCT is cis-acting. iz a gain of function.Razib Khanhttps://www.blogger.com/profile/09555115542918519593noreply@blogger.comtag:blogger.com,1999:blog-19346366.post-1165258764914012702006-12-04T13:59:00.000-05:002006-12-04T13:59:00.000-05:00Joel Hirschhorn of the Harvard Medical School has ...<I>Joel Hirschhorn of the Harvard Medical School has found that the block containing the lactase gene in lactose tolerant Europeans extends for about 1 million DNA units." What will happen to this block if the carriers breed outside the group of those who also carry it?</I><BR/><BR/>The existence of a "block" just means that the mutation giving lactose tolerance arose on a certain background. So the presence of this mutation is also correlated with other variation in a 1 million bp region. As time goes on, the size of the block will reduce due to recombination. <BR/><BR/>If people with the mutation breed with people that don't, the mutation will just spread out in different populations. I'm pretty sure lactose tolerance is dominant, so that should mean more lactose tolerant people in the world (i.e. more heterozygotes). I'm not sure why this should be a "price". or a benefit, for that matter.Joe Pickrellhttps://www.blogger.com/profile/03756271491303196763noreply@blogger.comtag:blogger.com,1999:blog-19346366.post-1165135178613765692006-12-03T03:39:00.000-05:002006-12-03T03:39:00.000-05:00Combining the above with your thesis of symbiont/p...Combining the above with your thesis of symbiont/parasite manipulation sometimes yielding unexpected favorable result:<BR/>What if some populations expanded nepotism towards moderate ranges of genetic distance, beyond cousins,<BR/>but this turned out to be a manipulation of a lactobacteria, building on the <BR/>1 million DNA unit block,(lacP A)<BR/>getting it treated as if it represented the totality of the variable genes?<BR/>This is the hard case for bio-imagination to expatiate upon;<BR/>how can nepotism and reduced suspicion and hostility ever widen its circle in such degrees? That is, where genetic causation is to have a great role, and has to start from nothing, and not be free-rided out of its chance to exist.<BR/>Would some heritable preference for such a block as long as the above, be enough to generate the expanded nepotism and trust tendencies, strictly regarding genetic distance,<BR/>or would there have to be some additional push as from a microbial manipulation, such as the above-suggested?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19346366.post-1165046842922474222006-12-02T03:07:00.000-05:002006-12-02T03:07:00.000-05:00Re: lactose tolerance -- again, even if black-whit...Re: lactose tolerance -- again, even if black-white interracials were less tolerant of lactose than whites, this cost to whites would still be just one facet of the cost-benefit equation. I don't doubt that interracials will appear less fit in some ways -- "appear" since it may not actually affect fitness -- but I also don't doubt that they'll appear more fit in other ways. The net effect is too tricky to predict, I think.<BR/><BR/>The crude rule-of-thumb is to look at what environments the two separate pops are adapted to for all relevant traits. To the extent that they're similar, the interracials likely won't be any worse off -- and may actually exceed expectation if they've inherited two distinct, optimal solutions that their parental pops have independently discovered. To the extent that they're different, the interracials will be torn in differing directions, not being optimal in either of their parents' ancestral environments.<BR/><BR/>To take an example close to home for me, interracials of northern Euro and northeast Asian descent will likely reach or exceed expectation for IQ, since both N.Europen and NE.Asian environments have selected for higher IQ. On the other hand, the optimal personality -- or range of personalities -- may be different for N.Europe and NE.Asia. <BR/><BR/>Suppose it pays to be more clan-ish in NE.Asia than in Individualist N.Europe: then selection will make NE.Asians more suspicious of others. At first a few genes of large effect will make NE.Asians pretty darn suspicious, though over time modifying genes will temper this to a less extreme level. As a result, you have a co-adapted gene complex responsible for current levels of suspiciousness among NE.Asians.<BR/><BR/>But what if that complex is broken up by mating w/ more trusting N.Europeans? An interracial kid may get the uber-suspicious allele from the NE.Asian parent but not the modifying genes, so they'll appear even more suspicious & mistrusting than expectation. I don't know of any studies looking at this, and it's hard to judge others since suspicion & mistrust is a pretty private thing. But for me, my 2 brothers, and my dad, I'd say this isn't far off from the truth. (My dad's 1/2 Euro / Japanese, his sons are 1/4 Jap.)agnostichttps://www.blogger.com/profile/12967177967469961883noreply@blogger.comtag:blogger.com,1999:blog-19346366.post-1164958838977559482006-12-01T02:40:00.000-05:002006-12-01T02:40:00.000-05:00In an odd twist of science, though, we have those ...In an odd twist of science, though, we have those who make absolute statements to the effect that there is no reason to discourage interracial interbreeding, while moderate and cautious statements to the contrary are treated to ad hominem vilification.<BR/>If nothing much is at stake here, why the passion and enthusiasm to ditch the ordinary prudence of diction among scientists?<BR/>On p.136 of Nicholas Wade's Before the Dawn, there is mentioned that "Joel Hirschhorn of the Harvard Medical School has found that the block containing<BR/>the lactase gene in lactose tolerant Europeans extends for about <BR/>1 million DNA units."<BR/>What will happen to this block<BR/>if the carriers breed outside the group of those who also carry it?<BR/>Isn't this a potential price that we're not being told about, when it <BR/>is said that there is nothing to lose by such means?<BR/>These questions are not rhetorical; I'm not sure what exactly should be expected to happen in such cases or how fast.Anonymousnoreply@blogger.com