tag:blogger.com,1999:blog-3734925856292601239.post2214708319804937304..comments2024-03-22T15:55:34.030-04:00Comments on Evo and Proud: Common genetic variants and intelligencePeter Frosthttp://www.blogger.com/profile/04303172060029254340noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-3734925856292601239.post-81064879291068397732008-10-03T10:50:00.000-04:002008-10-03T10:50:00.000-04:00Billy Buzz,"one gene accounting for the entirety o...Billy Buzz,<BR/><BR/>"one gene accounting for the entirety of population variation in a continuous trait."<BR/><BR/>This seems to be the source of our misunderstanding. The hypothesis is that one gene may account for most genetic variation in performance on IQ tests. There are three things to keep in mind:<BR/><BR/>1. There are still many other IQ-linked genes in the picture. <BR/><BR/>2. Around 40% of variation in IQ is non-genetic. <BR/><BR/>3. This gene may not exhibit a simple dominant/recessive mode of expression.<BR/><BR/>So you could still get a smooth normal distribution of IQ even though most of the genetic variation is being generated by one gene.<BR/><BR/>Having said all of that, I am skeptical. We may be looking at several genes that are close to each other on the same chromosome. Or the single-gene hypothesis may be wrong. <BR/><BR/>On a final note, while I disagree with this hypothesis, I don't try to misrepresent it.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-76593026147184956552008-10-02T23:27:00.000-04:002008-10-02T23:27:00.000-04:00"But I've heard that argument made (and the word '..."But I've heard that argument made (and the word 'most' should be underlined). A quick search turned up this web article:"<BR/><BR/><BR/>Oh, come on! This was covered in my last comment. There is a difference between pleiotropy (one gene having multiple effects in the same organism) and one gene accounting for the entirety of population variation in a continuous trait.<BR/><BR/>The former IS very strongly implied by g, the latter is completely incoherent. The latter requires a large number of different alleles by definition.<BR/><BR/>Differences can't be explained by the same thing: by definition they must be explained by different things.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-39776339215257244092008-10-02T21:47:00.000-04:002008-10-02T21:47:00.000-04:00First, I don't believe that a single gene accounts...First, I don't believe that a single gene accounts for most variation in IQ. But I've heard that argument made (and the word 'most' should be underlined). A quick search turned up this web article:<BR/> http://home.ipoline.com/~hhk/JQ-issue.htm<BR/><BR/>"Intelligence, being such a complex combination of attributes and cognitive abilities would obviously be related to a large number of different genes. A surprising recent finding was that a single gene could also influence numerous other abilities."Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-60929709197553747282008-10-02T17:31:00.000-04:002008-10-02T17:31:00.000-04:00Many people believe that? Who?And again, it's a lo...Many people believe that? Who?<BR/><BR/>And again, it's a logical statement. Correlated intelligence factors "implies" one gene is responsible for intelligence differences by what logic?<BR/><BR/>(It definitely implies different cognitive abilities like math, memory, and spatial skills have broadly overlapping genetic pathways. But I just don't get how it possibly would suggest the thing you say)<BR/><BR/>How could seven standard deviations of heritable, strictly additive intelligence score differences all be due to one gene? I don't think that is even possible.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-44986878045858414522008-10-02T10:16:00.000-04:002008-10-02T10:16:00.000-04:00Billy Buzz,My writing style may have confused you....Billy Buzz,<BR/><BR/>My writing style may have confused you. I was putting into words what many people believe when I wrote: "Doesn’t g imply that one gene accounts for most genetic variation in intelligence?"<BR/><BR/>Personally, I don't know.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-35664925175277356432008-10-01T18:12:00.000-04:002008-10-01T18:12:00.000-04:00You said "one gene", not many genes close together...You said "one gene", not many genes close together.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-71541795871162933962008-10-01T11:00:00.000-04:002008-10-01T11:00:00.000-04:00Billy Buzz,Why couldn't it be due to genes that ar...Billy Buzz,<BR/><BR/>Why couldn't it be due to genes that are physically close to each other on the same chromosome?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-46048499222875757542008-09-30T02:46:00.000-04:002008-09-30T02:46:00.000-04:00Doesn’t g imply that one gene accounts for most ge...<I>Doesn’t g imply that one gene accounts for most genetic variation in intelligence? Perhaps.</I><BR/><BR/>No, not "perhaps". How can seven standard deviations of continuous phenotypic variation, that is almost entirely heritable be the result of one allele? Variation can't be "additive" if there is nothing to add.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-84128013120642890492008-09-26T23:56:00.000-04:002008-09-26T23:56:00.000-04:00He says he thinks that no significant genetic diff...<I><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.<BR/></I><BR/><BR/>I am surprised that someone who understand natural selection could make such a stupid statement.<BR/><BR/>Different human environments require different survival skills and different amounts of cognitive skills. Cognitive skills are largely required in complex social environments. Until 200 years ago, Aboriginal Australians did not live in socially demanding environments, unlike a great many people in, say, China and Europe.<BR/><BR/>Natural selection optimizes for the local environment. If cognitive skills are not needed, selection is not going to select for them, given how expensive the brain it.<BR/><BR/>This is evolution 101. Get real.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-2423821425728640992008-09-25T11:09:00.000-04:002008-09-25T11:09:00.000-04:00I suspect that most diseases do not have a genetic...I suspect that most diseases do not have a genetic basis. They are probably chronic low-grade infections that co-exist with the human organism without triggering an immune response. <BR/><BR/>This is, after all, what evolutionary theory would predict. It's not in the germ's interest to kill its host. It just wants to use him or her as a milk cow. Eventually, this low-grade infection will harm the host, but by then the germ may no longer be detectable. It may even be gone.<BR/><BR/>I agree with your second point. He was probably using foreign students at American universities -- hardly an unbiased sample. In any case, you would have to use large samples to obtain any measurable effects. There may be one big gene that accounts for most variation in IQ, but most of the other IQ-related genes probably have very small effects.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3734925856292601239.post-61251185425980091322008-09-24T13:52:00.000-04:002008-09-24T13:52:00.000-04:00If Dr. Goldstein was correct in believing that (m...If Dr. Goldstein was correct in believing that (many different) rare varients are causing one illness across a population, it means that each clearly identifiable disease is usually caused by different genes in different people. In that case it is astounding that a disease appears in more or less the same form in most people. <BR/><BR/>It has long been suggested schizophrenia is not one disease. I expect this is because the medical geneticists familiar with the familial studies have long been saying that there is no evidence for it's genetic causation.<BR/><BR/>Dr Goldstein bases his conclusion of no significant IQ differences on the testing of volunteers "of all races", but those who volunteer for such testing would tend to be the more intelligent. He needed to add 2000 of the typical non-volunteers to the study to be justifyed in drawing any conclusion.<BR/><BR/> His negative results may be due to the study being across races. Surely studying the IQ and genetic variation <I>within families</I> would reduce the size of the "haystack".Anonymousnoreply@blogger.com