tag:blogger.com,1999:blog-37148773.post2790363680611145762..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Genetics and RaceLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger38125tag:blogger.com,1999:blog-37148773.post-55925268732555440212008-09-21T11:52:00.000-04:002008-09-21T11:52:00.000-04:00There is no such thing as "genes that lead to inte...There is no such thing as "genes that lead to intelligence". Genes are necessary but without the adequate nutrition and cultural-learning environment, they don't lead to even normal levels of intelligence. <BR/><BR/>Genes are involved in basic, "physiological" scaffolding; their variation only causes large decreases, never increases, of intelligence. For variation within the "normal", upper range of IQ, the effect of genetic variation is negligible.<BR/><BR/>It is also interesting to point out here that some of the "degenerative" mutants can be rescued by nutrition, conversely, some non-mutants can have severely abnormal phenotypes (e.g.autism), all of which indicate the environment is involved in the very basic scaffolding, too.<BR/><BR/>Say we find that some ethnic-racial group have higher frequencies of genes that produce severe mental problems (for instance, a deletion leading to prader-willi). Or that they have higher incidence of microcephaly. Sure, they contribute to the variation of the IQ of that population. You are going to find things like that. Would you then argue that the race is genetically of a lower IQ? Nobody will be jumping to that conclusion since it is misleading about the variation in the upper, normal range of IQ in that group. <BR/><BR/>Some have brought up the possibility of variation of neural-brain genes causing small, hard-to-detect effects (increases or decreases), using statistics to detect correlations. Of course the best low tech thing thing would be to acccumulate these effects by artificial selection for high IQ; some historical attempts suggest it doesn't work. <BR/><BR/>Looking for statistical correlations is fine but we have to understand the level to which the entire question has been removed. We are asking ourselves about the existence of hard-to-detect genes with "small" effects on intelligence and the answer is almost always stuck in "maybe". <BR/><BR/>The other thing we may find is a higher frequency ina given group of a gene that has been argued to have a small, hard-to-detect effect (positive or negative). That may be so, but again, notice how far removed this question is from the terms of discussion of misinformed people who are wondering, for instance, whether it is a waste to educate blacks! <BR/><BR/>Some think that a given race may have an accumulation of several small-effect genes. If so, outbreeding from one race into another "non-enriched" race should "dilute" the genetic IQ of progeny, much like when you outbreed an artificially selected "race"; if several small-effect genes are accumulated, the trait will be significantly diluted. Nothing like that happens with IQ, of course.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-72262068946473040722008-09-18T13:29:00.000-04:002008-09-18T13:29:00.000-04:00Sorry that I could not help you.I might read the p...Sorry that I could not help you.<BR/>I might read the papers...A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-63508383962426106552008-09-18T11:41:00.000-04:002008-09-18T11:41:00.000-04:00"Bryan, you either whine we are not looking, or bo..."Bryan, you either whine we are not looking, or bonk the table and say we already have the evidence... make up your mind, dudrness."<BR/><BR/>Maybe try reading what I wrote before you reply next time; you'll look a little less dumb that way.<BR/><BR/>Its blatantly clear from my reply that I don't think we've looked into the issue to any extent. Its also very clear from my reply that there are researchers in the area (i.e. their opinion, not mine) who think the evidence says there is a strong genetic link.<BR/><BR/>I even provided a citation to an article where the authors (who once again, are not me) make that very claim.<BR/><BR/>I've been perfectly consistent in my statements. I'm sorry for confounding the issue by introducing the statements of others; apparently that was too much for you to follow.Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-42168774733581790402008-09-18T10:43:00.000-04:002008-09-18T10:43:00.000-04:00Bryan, you either whine we are not looking, or bon...Bryan, you either whine we are not looking, or bonk the table and say we already have the evidence... make up your mind, dudrness.<BR/><BR/>I doubt those papers are good evidence. I may have alook into them, ut it's bound to be more of the same of this speculativ-crappy brand of "evolutionary psychology" science.<BR/><BR/>Have a nice dayA. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-52320463185638671572008-09-17T19:11:00.000-04:002008-09-17T19:11:00.000-04:00John, thanks for that informative reply. It answer...John, thanks for that informative reply. It answered my question perfectly.Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-3371884360273564532008-09-17T19:05:00.000-04:002008-09-17T19:05:00.000-04:00This comment has been removed by the author.Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-74322394018101173222008-09-17T19:04:00.000-04:002008-09-17T19:04:00.000-04:00Sanders wrote: "IQ does not associate signifi...Sanders wrote: "IQ does not associate significantly...What do you think that tells you about genetic differences of IQ between races?"<BR/><BR/>Based on a brief look at what's in pubmed, I'd have to stand by my original statement - we really haven't looked.<BR/><BR/>That said, my pubmed search did find several studies that claimed genetic-based differences in IQ among racial groups - see the work of JP Rushton, AR Jensen, and L He for some examples.<BR/><BR/>On example, from a joint paper between Rushton & Jenson:<BR/><BR/><I>The preponderance of evidence demonstrates that in intelligence, brain size, and other life-history variables, East Asians average a higher IQ and larger brain than Europeans who average a higher IQ and larger brain than Africans. Further, these group differences are 50-80% heritable</I><BR/><BR/>PMID: 18656315<BR/><BR/>My (granted brief) look at the issue makes me think that they are overstating the case, but regardless, at least three experts in the area think there is evidence to support a claim of differential IQ's between races.<BR/><BR/>If IQ truly represents our intelligence is another issue all together...Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-90114474466993999342008-09-17T11:47:00.000-04:002008-09-17T11:47:00.000-04:00Lets say there are two genes - gene A and gene B -...<I>Lets say there are two genes - gene A and gene B - that become enriched in a population. A through natural selection, B through drift. Both end up enriched to a similar extent.<BR/><BR/>Would the statistical methods be able to differentiate between the mechanisms that lead to A being enriched verses B?<BR/><BR/>If so, how?</I><BR/><BR/>Assuming that in both A and B originated from single mutations, positive natural selection will cause A to become common <B>vastly faster</B> than drift can cause B to become equally common. So if A and B are the same current frequency, the selected allele A should be much younger than B. <BR/><BR/>Methods for detecting positive natural selection depend on identifying allele age, mostly by linkage decay. Recombination breaks up linkage over time; an allele that has a high current frequency and has maintained linkage over a very wide region is very young. <BR/><BR/>These methods do not distinguish other kinds of selection, such as balancing selection, and they are ineffective on rare alleles (for which we have insufficient data to estimate linkage decay).John Hawkshttps://www.blogger.com/profile/17027862713126904206noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-82679195911953442942008-09-17T11:03:00.000-04:002008-09-17T11:03:00.000-04:00IQ does not associate significantly with race when...IQ does not associate significantly with race when people are raised in the same educational institutions and similar socio-economic condition.<BR/><BR/>What do you think that tells you about genetic differences of IQ between races?A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-80572453451908000972008-09-17T11:02:00.000-04:002008-09-17T11:02:00.000-04:00This comment has been removed by the author.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-76973146859345950402008-09-17T10:57:00.000-04:002008-09-17T10:57:00.000-04:00Before we look if there's genetic differences in I...Before we look if there's genetic differences in IQ, it would be a good idea to be able to identify IQ genes first, nope? Pubmed that!<BR/><BR/>The results are disappointing; and this particular search has been going on with sufficiently modern tools for quite some while now<BR/><BR/>Maybe this can explain why taking it to the race level with such flimsy data is not such an attractive questA. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-66931475818108144582008-09-17T09:44:00.000-04:002008-09-17T09:44:00.000-04:00Sanders wrote: "Are you sure? Truly significant ge...Sanders wrote: "Are you sure? Truly significant genetic effects don't need all that tech to be detected."<BR/><BR/>I am sure - traits such as intelligence will most likely be multi-genic, and the tools for identifying those are rather new. We're still finding new risk genes involved in "obvious" processes like diabetes and other autoimmune disorders. A pubmed search shows no such attempt at finding intelligence genes.<BR/><BR/>"Single mutations of great effect always, lower, but never enhance, intelligence."<BR/><BR/>That we know of - genes which cause medically identifiable disorders are always much more obvious than genes with neutral, or slightly advantageous effects. And, as I pointed out before, I could not find any evidence in pubmed that such a search has taken place.<BR/><BR/>Besides, who said anything about single genes? Intelligence is most likely a combination of multiple genes and our environment. And until we look (and a pubmed search revealed no evidence that we've looked) we have no way of knowing if certain genes that lead to intelligence are concentrated in one race verses another.<BR/><BR/>And even if all neuronal-based mutations lead to less intelligence, there is no reason why those detrimental genes could be enriched in a race/population. <BR/><BR/>Keep in mind that we're talking about racial-associated traits here. It doesn't have to be more intelligence to occur; it can be less intelligence, something immune, or something else all together.Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-43734724342962325412008-09-17T04:28:00.000-04:002008-09-17T04:28:00.000-04:00|| PaleoFreak said... "How many black African r...|| PaleoFreak said...<BR/><BR/> "How many black African races are there?"<BR/><BR/> Good question :-D<BR/> Let's count. There are the the Bushman Blacks, the Pigmy Blacks, the Tall Blacks, the Jungle Blacks, the Thick Bearded Blacks, the Dessert Blacks, the Blacks that Can Run A Lot, the Brownish Blacks of the North (like me), the Very Black Blacks, and of course the Common Blacks.<BR/><BR/> Tuesday, September 16, 2008 6:33:00 PM ||<BR/><BR/>And, PaleoFreak, I think the Monty Python team wants to hear from you :^)shonnyhttps://www.blogger.com/profile/07709590949815668561noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-5144193881801673852008-09-16T19:21:00.000-04:002008-09-16T19:21:00.000-04:00In Response to anonymous. To paraphrase Stephen J...In Response to anonymous. To paraphrase Stephen Jay Gould: The definition of black is someone with skin dark enough that we can call them black. <BR/><BR/>In response to Bryan: There must be races because we look different. What is your point? How does that in any way validate the concept of genetic difference? There may be differences that you think that you can "see" that don't really have any meaningful application in genetics. You could say that a Canadian (of english descent) looks different from a northern European, does that mean they are different races?Anonymoushttps://www.blogger.com/profile/08023731953765453577noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-47946865719538971362008-09-16T19:20:00.000-04:002008-09-16T19:20:00.000-04:00"There is no underlying reason why enrichment of a..."There is no underlying reason why enrichment of alleles that would give enhanced intelligence (or whatever) could not occur in a racial group"<BR/><BR/>The absence of evidence is actually quite understadable when you abandon the world of mere statistic correlations and consider some hard brain plasticity data from experimental and developmental psychology. Genes are necessary to develop intelligence, but they are also insufficient to attain even normal intelligence levels. This is a complex trait. Single mutations of great effect always, lower, but never enhance, intelligence. Ever wondered why, and what are the implications? <BR/><BR/>"We haven't done a good job of looking for it"<BR/><BR/>Are you sure? Truly significant genetic effects don't need all that tech to be detected. <BR/>Take into account, this was considered to be a fact "plain and simple" for a veeery long time. Even after WW II made it decidedly wrong to be racist, only in the 70's do we start unmasking the shameful frauds and crappy science that was behind the supposed "established facts" of racial differences of intelligence.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-7071101214282034392008-09-16T18:41:00.000-04:002008-09-16T18:41:00.000-04:00"There aren't. If there is any hard evide..."There aren't. If there is any hard evidence for such a thing, I haven't seen it."<BR/><BR/>Absence of proof is not proof of absence.<BR/><BR/>We do see some alleles enriched in some races/populations - CFTR ΔF508, G542X, G551D, N1303K & W1282X in Caucasians, HLA-A*6802 and HLA-B18 in sub-Saharan Africans, etc. <BR/><BR/>There is no underlying reason why enrichment of alleles that would give enhanced intelligence (or whatever) could not occur in a racial group. We haven't done a good job of looking for it; that doesn't mean it cannot and has not happened.Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71267577808110230652008-09-16T18:36:00.000-04:002008-09-16T18:36:00.000-04:00But they tend to differ from one race to another b...<I>But they tend to differ from one race to another because each human population, after the dispersal from Africa some 50,000 years ago, has had to adapt to different circumstances.</I><BR/><BR/>While the word "adapt" raises the obvious red flag about strict adaptationism, I read that sentence and thought "But what about gene flow?"<BR/><BR/>Allelic differences between human geographic populations (using a pretty fuzzy definition of "population", here) must surely be influenced by a past history of gene flow between populations, as well as drift, mutation, and selection.<BR/><BR/>---<BR/><BR/>As for censorship, self- or otherwise, it seems both extremely difficult and extremely unlikely for any branch of science to be effectively suppressed, barring massive financial barriers to entry into the field. Genetic analysis technology is now advanced to the point that human population surveys are probably limited more by airline prices accessing remote regions and isolated populations than by lab equipment. And there are so many journals and publishers that should any one publisher institute some kind of not-publish-that-topic policy, any interesting research will probably show up pretty quickly elsewhere.TheBrummellhttps://www.blogger.com/profile/08973380652057861796noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-74144839126392504092008-09-16T18:33:00.000-04:002008-09-16T18:33:00.000-04:00"How many black African races are there?"Good ques..."How many black African races are there?"<BR/><BR/>Good question :-D<BR/>Let's count. There are the the Bushman Blacks, the Pigmy Blacks, the Tall Blacks, the Jungle Blacks, the Thick Bearded Blacks, the Dessert Blacks, the Blacks that Can Run A Lot, the Brownish Blacks of the North (like me), the Very Black Blacks, and of course the Common Blacks.El PaleoFreakhttps://www.blogger.com/profile/11323149141956089390noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-35071587699141345582008-09-16T18:31:00.000-04:002008-09-16T18:31:00.000-04:00I have a question about the statistical methods us...I have a question about the statistical methods used to measure selection.<BR/><BR/>Lets say there are two genes - gene A and gene B - that become enriched in a population. A through natural selection, B through drift. Both end up enriched to a similar extent.<BR/><BR/>Would the statistical methods be able to differentiate between the mechanisms that lead to A being enriched verses B?<BR/><BR/>If so, how?<BR/><BR/>Just curious; I took population genetics in the pre-genomics era, so I don't think this stuff was part of the curricula...Bryanhttps://www.blogger.com/profile/16672407110077541595noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-3756481303156271382008-09-16T18:19:00.000-04:002008-09-16T18:19:00.000-04:00In this paper:Nei, M. (2007) The new mutation theo...In this paper:<BR/><BR/>Nei, M. (2007) The new mutation theory of phenotypic evolution. PNAS, 104, 12235-12242.<BR/><BR/>Nei says:<BR/><BR/><I>Most molecular evolutionists are well aware of the importance of mutation in protein evolution. Yet, many investigators are trying to identify even the slightest trace of natural selection using various statistical methods (99–102). Using these methods, a number of authors have reported that a substantial proportion of amino acid substitutions are caused by positive Darwinian selection (103–106). However, the statistical methods used are based on many assumptions, which are not necessarily satisfied with actual data (18, 107, 108). Furthermore, their estimates of selection coefficients are often of the order of 10–6 (100, 106) and are unlikely to affect gene function (18). Note also that although these authors emphasized natural selection, they are actually estimating the proportion of mutations that are adaptive.</I><BR/><BR/>I wonder what John and other positive selection folks think of this critique? <BR/><BR/>The paper can be read here:<BR/><BR/>http://www.pnas.org/content/104/30/12235.fullSteveFhttps://www.blogger.com/profile/06089429778294973157noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-68748473566949480932008-09-16T18:14:00.000-04:002008-09-16T18:14:00.000-04:00Also from the NYT profile: "He says he thinks t...Also from the NYT profile:<BR/><BR/> "He says he thinks that no significant genetic differences will be found between races because of his belief in the efficiency of natural selection. Just as selection turns out to have pruned away most disease-causing variants, it has also maximized human cognitive capacities because these are so critical to survival. “My best guess is that human intelligence was always a helpful thing in most places and times and we have all been under strong selection to be as bright as we can be,” he said.<BR/><BR/> This is more than just a guess, however. As part of a project on schizophrenia, Dr. Goldstein has done a genomewide association study on 2,000 volunteers of all races who were put through cognitive tests. “We have looked at the effect of common variation on cognition, and there is nothing,” Dr. Goldstein said, meaning that he can find no common genetic variants that affect intelligence. His view is that intelligence was developed early in human evolutionary history and was then standardized."<BR/><BR/>That makes sense to me. Anyone disagree?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-26137959907643627922008-09-16T18:05:00.000-04:002008-09-16T18:05:00.000-04:00Do most of the races of the world have black skin ...Do most of the races of the world have black skin and remain in Africa? How many black African races are there?<BR/><BR/>Would the Caucasian, Mongolian, and Autralian Aboriginal races (for example) have diverged from one particular (black skinned) race in Africa, and spread out over the world, while many other black skinned races remained in Africa?crfhttps://www.blogger.com/profile/10726414637021391906noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-87289633324482734372008-09-16T16:47:00.000-04:002008-09-16T16:47:00.000-04:00"so while we may find that some races are "enriche..."so while we may find that some races are "enriched" in genes that make them smarter (or whatever), its unlikely to be a trait found in ever member of a race"<BR/><BR/>The point that not every member of a race will be the same is obvious; the only point of discussion is whether there are any such "enriched" races or not. <BR/><BR/>There aren't. If there is any hard evidence for such a thing, I haven't seen it. Of course, there is tons of phony articles based on weak evidences; it's not like no one is trying. It's just they seem unable to ever progress beyond the "hypothesis" phase.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-72308511469968286902008-09-16T16:43:00.000-04:002008-09-16T16:43:00.000-04:00From the very interesting (about stuff you might b...From the very interesting (about stuff you might be surprised to find there's so far no demonstrable genetic component of) http://www.fims.org/default.asp?pageID=782860264 , here's a relevant snippet:<BR/><BR/>"Recent data from the HapMap study, which aims to characterise human genetic variation by genotyping African, Asian and European individuals, show values between 7 and 12% of total genetic variation attributable to between-population differences. Similarly, the data shows that haplotypes (linked segments of genetic variation, rarely subject to reassortment by recombination) are shared across populations 28. Indeed, the level of genetic diversity between human populations is not large enough to justify the use of the term ‘race’ (see Jobling et al. 29 for a review). Consequently, any differences in physiology, biochemistry and/or anatomy between groups defined solely by skin colour (e.g. comparing ‘black’ with ‘white’) are not directly applicable to their source populations, even if the differences found are indeed genetically determined."Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-49331506469297551152008-09-16T16:28:00.000-04:002008-09-16T16:28:00.000-04:00You mean "palau man" John Hawks? heheheAbout signa...You mean "palau man" John Hawks? hehehe<BR/><BR/>About signatures of selection at sequence level, I'd recommend you read this: <BR/><BR/>Hughes, AL (2007)Looking for Darwin in all the wrong places: the misguided quest for positive selection at the nucleotide sequence level<BR/>Heredity 99, 364–373 <BR/><BR/>When selection is inferred from a supposedly higher than normal population frequency, this usually implies making several assumptions about the history and current structure of a population.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.com