Home > Uncategorized > Race, genes, & intelligence, part 0

Race, genes, & intelligence, part 0

This is divided into three sections:
A. Clarifications
B. The plausibility of the Hereditarian Hypothesis
C. The likelihood of socially important genetic differences between populations
D. The reasonability of positing the Hereditarian Hypothesis

A. Clarifications

Motivation

My interest is not in convincing anyone that this or that subpopulation phenotypic difference has a partial genetic etiology, but rather in forcing an empirical test of the genetic hypothesis and resolving this issue once and for all. To do that, it is necessary to demonstrate (to the public and misinformed members of academia) that this is a yet unresolved issue of pressing social importance. Levin (1997), Jensen (2000), Gottfredson (2005), Sesardic (2005), and Hunt and Carlson (2007) have laid out the case for bringing closure to the issue; those interested are left to bring the matter to public consciousness and to challenge those believers in the reigning paradigm to subject their prejudices to investigation. This issue, for the most part, can be resolved in a matter of months. With regards to the questions of evolved ancestral differences, Rowe (2005), Rushton and Jensen (2005), Murray (2005), Hunt and Carlson (2007), and Lee (2009) have already discussed the proper tests that would provide dispositive results: admixture studies. Such studies, which are now commonly done (see: Winkler et al., (2010), Admixture Mapping Comes of Age) to locate the origins of medical disparities would, if properly done, end this debate.

Clarification about the Concept of Race

On the matter of biology and race, there seems to be considerable confusion, no doubt artfully sowed. Given that, let me clarify: When it comes to the hereditarian hypothesis, we are not discussing the philosophy of biology — I discuss some aspects of that here — we are discussing the etiology of differences between socially identifiable ethnoracial groups. These groups represent different biological population structures. The assumption here is not that these ethnoraces are taxonomically identifiable groups or that there are clear boundaries between these groups, but rather that the said groups have different population structures. When the Human Genome Project states that “DNA studies do not indicate that separate classifiable subspecies (races) exist within modern human,” they are talking about biological taxonomic classifications and saying that there are no population specific genes that would warrant classifying various populations as subspecies. That is a separate issue. (See: 70-71). With regards to the current discussion, we are starting with socially identified ethnoracial groups which have different population structures and asking: “Why are there behavioral differences?”


McEvoy, et al., 2010. Whole-genome genetic diversity in a sample of Australians with deep Aboriginal ancestry



Trishkoff, 2010. The Genetic Structure and History of Africans and African Americans

Race concepts, nonetheless

Since the mantra of “race is a social construct (RISC)” is often intoned to ward of the specter of Jensenism, a little more clarification is, perhaps, needed. The “RISC” concept comes by way of Lewontin. Unlike many of our contemporaneous academic charlatans who peddle the “RISC” concept, Lewontin was kind enough to provide criteria for falsifiablity. According to Lewontin (1972), RISC means that racial classification are of “virtually no genetic or taxonomic [superfamily to subspecies] significance.” The scientific community has since rejected the notion that race, whether delineated by continental, sub-continental, or regional ancestry (lumpers and splitters), is of no such significance. [2, 17, 22, 28, 42, 44, 62, 69, 71]. (The root of “race” is “ancestry,” word games about “lactose intolerant races” notwithstanding). The RISC hypothesis has been falsified and Lewontin’s claim about race is now know as Lewontin’s fallacy.

None of the above has stopped many (every other social “scientist”) from asserting that RISC is, nonetheless, true. Often, a sleight of hand is pulled and, while the pretense that race is of “no genetic or taxonomic significance” is maintained, RISC is redefined to mean that racial classifications do not represent subspecies; some go so far as to baldly claim that “the social construction of race,” now redefined to mean the lack of consensus concerning the taxonomic status of race, contradicts the biogenetic concept of race (e.g. Smedley, 2005). (It’s worth noting that in many parts of the world,, the race concept has wide currency; see: Lieberman et al., 2004. The race concept in six regions: variation without consensus).

To emphasize again, with regards to the Hereditarian hypothesis and the question of mean differences between socially classified subpopultions, whether or not there are human subspecies and whether everyone fits neatly into some grouping is immaterial. What is presupposed is that different racial (read: regional ancestral) classifications describe, on average, sets of individuals with different (average) ancestries. See: A defense of the Race concept.

Clarification about the meaning of general intelligence

General intelligence (g) can operantly be defined as the property that both IQ and Reaction time tasks measure. A more technical definition is the “substantial covariation among diverse measures of cognitive ability as indexed by an unrotated first principalcomponent score, which typically accounts for about 40% of the total variance of diverse cognitive tests, or by a total score across diverse tests as is done in intelligence tests ” (Plomin and Spinath, 2004. Intelligence: Genetics, Genes, and Genomics).

The educational, social, and psychological, and neurophysiology correlates of g are well established; no other phenomena has been as well researched in psychology as that of general intelligence. For a good review of the empirical findings refer to Deary et al. 2010. The neuroscience of human intelligence differences. There is some debate as to whether g represents a causal entity or whether it is epiphenomenal. For a good discussion of this, refer to: Gottfredson, 2010. Intelligence and Social Inequality: Why the Biological Link?. This is an interesting question, but as differences in g are highly predictive of social outcomes, it does not matter if g represents a causal entity, if g represents a set of correlations tied to causal entities (e.g different neural functions), or if g magically recruits the environment to cause the predicted social outcomes. Differences in g matter.

Clarification about the Meaning of Average differences

When we talk about group differences, with respect to population genetics, we are talking about mean averages. Mean averages are an abstraction. They do not say anything about individual performance. (Whether or not probabilistic calculations based on these means is morally acceptable, is another issue.) As such, if you are naturally at the right tail end of some measure, you are at the right tail end.

Gottfredson, 2005. Social Consequences of Group Differences in Cognitive Ability

Clarification about the meaning of heritability

To say that a difference is heritable is to say that, given equal conditions, individuals or groups will differ as a result of genetically conditioned endogenous factors. With regards to the issue of heritability and malleability, we can quote Jensen (1973):

The proportion of variance indicated by [environmentality] , if small, does in fact mean that the source of environmental variance are skimpy under the conditions that prevailed in the population in which h^2 was estimated. It means the already existing variations in environmental conditions are not a potent source of phenotypic variance, so that making the best variations available to everyone will do little to reduce individual differences. This is not to say that yet undiscovered (or possibly already discovered but rarely used) environmental manipulation of forms of intervention .. cannot in principle markedly reduce individual differences in a trait which under ordinary conditions has very high heritability (Jensen, 1973).

Johnson, Penke, and Spinath have a nice introductory discussion on the concept of heritability. (Johnson, Penke, and Spinath, 2011. Heritability in the Era of Molecular Genetics: Some Thoughts for Understanding Genetic Influences on Behavioral). The only comment I would make is that they seem to error in this statement: “First, it is not 60% of the phenotype that is passed on to the next generation, or even 60% of genes related to deviation from the original population average in any way that has any meaning for the individual in that next generation.” They seem to suggest that heritability estimates only concern populations and are irrelevant to individuals. This is not the case, however, as individual genetic value is probabilistically related to population heritablility. For a good discussion of this, refer to Tal, 2009. From heritability to probability.

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  1. Reader
    December 11, 2012 at 4:31 pm

    ..

    Here’s an HBD Dictionary:

    http://www.humanbiologicaldiversity.com/#Dictionary

    ..

  2. March 11, 2014 at 8:49 am

    Scientist discover link between Racist, Conservative ideologies & low IQ

    http://m.huffpost.com/us/entry/1237796/

    • Chuck
      March 11, 2014 at 2:13 pm

      What’s your point, specifically?

      • March 11, 2014 at 9:02 pm

        My point is the above under standing of the data is flawed & one primary reason this data is viewed as linked to a genetic source of low IQ amongst groups is racism. In otherwords even intelligent racist would be that much smarter if they did not have racist preconceptions. I agree on the surface this data is daming. But as academics & scientist we must rule out all other possible stimuli that could effect IQ. The systemic & systematic racism Blacks have encountered through out the 300 or more years in North America is well documented but scientist & researcher with racist preconceptions refuse or simply cannot see the psychological, economic, educational & even medical effects of systemic racism. The phenomenon is so prevalent that you have psychologist Phillip J Rushton using a biological theory to prove Blacks are inherently inferior. As other academic racist his methods & conclusions are flawed. I point out

        1st we must know all the facts & properly analyze all the data &
        In here lies the rub. European and Asians also have bigger eyeballs. In fact all people living in and or native to northern latitudes have bigger brains and eyeballs. http://www.sciencedaily.com/releases/2011/08/110804214410.htm
        You can see this dynamic with in the populations living at varying latitudes in Europe. As you travel north in latitude studies show Northern Europeans have bigger eyeballs and brains than Southern Europeans
        This being the case the people with the biggest brains and eyeballs are Eskimos or the Inuit people who live near the North Pole. European and Asian brains are bigger in the areas dealing with sight. During the ice age it was dark and difficult to see. Also today due to sunlight refraction it is more difficult to see in Northern latitudes.
        Neanderthal man who was an early cousin to homo sapiens (us) evolved during the ice age and had a bigger brain than any human. http://www.sciencedaily.com/releases/2013/03/130319093639.htm

        We can tell from early Neanderthal artifacts they were less intelligent than homo sapiens archaic or homo sapiens sapiens(us/modern man) so their bigger brains did not equate to a higher intelligence. In fact it appears to have been substantially lower Europeans and Asians like Neanderthal developed in the northern hemisphere during ice age climatic changes. Both Asians and Europeans evolved bigger eyes and optic nerve areas to see better and developed bigger brains to deal with the extra sight sensory input
        So now we understand “why” Europeans and Asians have bigger brains. The next question is does this correlate with their inherently having a higher IQ than Africans?

        First lets look at two areas of the brain Asians and Europeans have increased size and have more grey matter dedicated to:

        The visual cortex . Again note this extra brain matter is dedicated to analyzing increased visual input. Another area larger in Asians and Europeans are the lateral ventricles.These are filled with cerebrospinal fluid (CSF) which bathes and cushions the brain and spinal cord . The lateral ventricles do not consist of any grey or white matter.

        Cognitive functions such as -executive functions, planning, abstract reasoning, impulse control, sustained attention and insight are not carried out in these areas. These functions are carried out primarily in the frontal lobe were the Orbitofrontal Cortex is located.

         African Americans in fact have a largerorbitofrontal cortex  than Caucasians.

        So knowing this we have to look into other reasons for higher intelligence scores in Whites & Asians. You have to analyze the psychological, economic & social effects on populations with traditionally lower IQ. Yes bigger brains due seemed to be tied to higher Intelligence but I theorize this-three average sized brained (as in average with in thier individual groups brain size & weight)African, Asian & Europeans would all have equalling average IQ as long as all three were raised with equal health, economic & educational access & minus the racism. It seens many researchers dont acknowledge the effect systemic racism has on a targeted population. Today we are comparing socially disadvantaged people’s some who come from pastrolist & hunter gatherings cultures. I theorize this is why Native Africans & East Indians score low in their native lands but those that immigrate to America score in the 100’s . Im Black, Beautiful & bloody brilliant. I was raised in one of the worst ghettos on the west coast. Those who suscribe to IQ being more an innate genetically influenced thing would say im some anomaly. I know im so smart because my mother read to me from the age of 2 or 3 or probably from birth but I cant remember this of course. By 3 or 4 I could read the children stories she used to read to me & dick & jane books utterly bored me. This is but one aspect of an environmental influence that pushed me to excel

      • Chuck
        March 11, 2014 at 10:16 pm

        I do not know what the phrase “racist preconceptions” means. Moreover, I don’t consider “racism” to be categorically morally problematic. See section V-H here: http://humanvarieties.org/2014/03/02/the-nature-of-race/ Let me know if you substantially disagree with any of the positions laid out. As for African Americans and “racism”, one’s interpretation will depend somewhat on one’s interpretation of the cause of the intelligence differences, differences which condition most outcome differences; to interpret the so-said effect of racism, we must first determine the cause of the group difference. An unbiased assessment of the facts might very well show that a historic legacy of slavery was a great boon to contemporaneous African Americans, as, on account of slavery, they reside in the prosperous West and not in less prosperous Black West Africa — and have benefited from the positive effects of introgression. Now you say:”1st we must know all the facts & properly analyze all the data”. I agree completely. Re-read what was said under: A. Clarifications: Motivation.

      • March 11, 2014 at 9:19 pm

        Sorry here are the proper links to some of my research
        Bigger brains & eyes in peoples from Northern Latitudes http://www.sciencedaily.com/releases/2011/08/110804214410.htm

        Neanderthals had bigger brains than modern humans

        http://www.sciencedaily.com/releases/2013/03/130319093639.htm

        Blacks have larger orbital frontal cortexs than Whites & Asians

        http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0013642

      • Chuck
        March 11, 2014 at 9:50 pm

        Due to its complexity, this topic is difficult to discuss in the comment section of a blog post. If you want to converse about it in detail, I will email you. If you want to write up an informed critique of the hereditarian position for a well read “HBD” blog which I am affiliated with (i.e., “Human Varieties”) I will arrange something. That said, a brief reply:

        The Isamah study you (and I) cite has a tiny sample size; also it shows a large total grey matter and total white matter size difference. This difference is consistent with the general intelligence difference, such differences are less distributed in specific regions. See here: http://onlinelibrary.wiley.com/doi/10.1002/hbm.22438/abstract;jsessionid=32DAAC19A07381D62ADE127E8CE2AB9C.f02t02?systemMessage=Wiley+Online+Library+will+be+disrupted+Saturday%2C+15+March+from+10%3A00-12%3A00+GMT+%2806%3A00-08%3A00+EDT%29+for+essential+maintenance&userIsAuthenticated=false&deniedAccessCustomisedMessage=

        Whatever the case, the brain size argument is rather weak. Black Africans do have smaller brains than White Europeans. And this is probably related to their lower average levels of mental ability. But my own (unpublished) review of data on differences in the U.S. gave equivocal results. That difference is seemingly much smaller. There is, then, a large contemporaneous Black African-African American difference, one which I presume is not simply due to the extensive European admixture in the AA population.

      • March 11, 2014 at 10:10 pm

        I agree it is difficult to dialogue on a complex topic on blog site. I will send you my email. Having said that I feel you have jump to a conclusion with data from only one possible source of low Black IQ. Psychological sciences are some what abstract, etheral even so I feel many who have done studies on IQ never factor in psychological stimuli for this reason. To do so would acknowledge racism past & present effects & would be more time consuming & intellectually challenging than basing your hypothesis on measurable data such as test scores & brain measurements.
        I agree genes play a role in all things IQ included . On indirect way genetics have affected my IQ is that im myopic or near sited

        http://www.nytimes.com/1988/12/20/science/study-links-intelligence-and-myopia.html

        It seems due to my poor site Ive forced to use hearing, smell & color & shape memory to recognize people & things. Thus Ive grown up using more areas of my brain than a person with 20/20 vision when looking at or reading something. This is a more direct & logical reason for my high IQ than some probable White genes I carry.
        I will read your links & send you my email via your site

      • Chuck
        March 11, 2014 at 10:30 pm

        I now primarily blog at ‘Human Varieties’. You can reach me at J122177(at)hotmail.com. If you are interested in the issue, for background you might start here: http://jaymans.wordpress.com/hbd-fundamentals/ We don’t focus on sociological effects because there’s a whole scientific discipline that does this i.e., sociology.

      • March 12, 2014 at 1:38 am

        Exactly Chuck you just as other academics do not precieve racism as you say problematic thus negate, do not study its effect & or refuse to acknowledge thier is an effect on targeted populations. This goes to my statement of preconceived racist notions. By negating racism as a factor negatively effecting African IQ you even suggest that by being brought to the West this was some sort of boon for Africans. This completely overlooks the fact that slave labor in part fueled both American & European economic might. No slavery no economically prosperous America. Unlike Spain & Portugal who looted Meso American gold & silver America began as an agricultural society thus cheap free labor helped pour untold trillions into the American economy. This is a version of the cultural racism many American be they Black White or turquoise unknowningly suffer from. I will read your links & I look forward to further dialogue with you.

      • Chuck
        March 12, 2014 at 1:23 pm

        I can’t discuss this topic with you if you can’t be logical. Either the psychometric intelligence gap is genetically conditioned or it’s environmentally so. To the extent the former, racial injustice, in the classic (and not neomarxist one), can’t be the cause of it or it’s consequences, both on the individual and population levels. To the extent the latter, racial injustice is a plausible cause. Your line of reasoning is, in this regards, a variety of petitio principii. Since I don’t rule out environmental factors, I don’t rule out effects of racial injustice, effects which must manifest in some specific environmental manner.

      • March 12, 2014 at 11:35 pm

        You stated “Moreover, I don’t consider “racism” to be categorically morally problematic.” Am I wrong in inferring from this response that by not considering racism to be “problematic” you also do not consider it important enough to investigate its possible effects or look into data from previous studies that have found racism to be highly damaging to health and intellect. If this is not what you meant I recede my question but your statement seems not only clear but familiar to me. Ive begged no question from you. I am not stating my argument proves something but rather disproves another argument so I believe applying the term “petitio principii” to my “line of thinking” is inaccurate. I stated that this is a line of thinking many Eurocentric researchers have. My line of reasoning is utterly logical. Not until you can rule out all posssibile factors such as psycho social ,socio economic and cultural stimuli you just cant declare one group is inherently more intelligent than the other. If an IQ test were to be given in 2014 bc north western Europeans would do horrible on it. The had not gained the technology nor the way opf thinking that would eventually propelled them to world dominance. They only true civilization in ancient Europe were the smaller brained southern European Greeks and Romans.
        This is not just data its a fact. Data can be viewed and interpreted through various lenses. Raw unbiased history cannot. History can be manipulated and fabricated but when you strip it to its truth what you see is what you get. By the big brain higher IQ theory Eskimos should be Einsteins but this is not so. Id watch Guns, Steel and Germs if you have not. it accurately explains why civilizations sprang up in some areas and in others people remained on a tribal or hunter gatherer level of existence

        I will not expand on this thought here but I will respond via email and fully explain my total argument on my blog about it on my blog at

        http://hucipher.wordpress.com/2013/07/28/the-big-brain-cipher-brain-size-iq-and-the-fallacies-in-j-phillippe-rushtons-theory/

  3. Chuck
    March 15, 2014 at 1:21 am

    Unfortunately, my lengthy reply was accidentally deleted — twice. This is why I don’t engage in discussions in the comment sections of blog posts. If you want to email me, do so. Later.

  4. Chuck
    March 18, 2014 at 12:50 am

    There are two primary disagreements here involved:
    (1) On logical, scientific, and moral grounds, I don’t feel that racial environmentalism — and, especially, racial injustice — should be the default position. I explained why in my “The Nature of Race” Paper.
    (2) I don’t consider it necessary to rule out every possible environmental explanation to rule in a genetic one. One can pit nature and nurture in general against each other using admixture mapping, biometrically informed structural equation modeling, GWAS allele counting, and genome-wide complex trait analysis. See, for example, here:

    Piffer, Davide. “Simple statistical tools to detect signals of recent polygenic selection.” Interdisciplinary Bio Central 6.1 (2014): 1.

    and here:

    Rowe, D. C., & Cleveland, H. H. (1996). Academic achievement in blacks and whites: are the developmental processes similar?. Intelligence, 23(3), 205-228.

    • March 23, 2014 at 6:01 pm

      Ive also have had trouble posting but here goes my long winded responce.

      Ill search for a link to your “nature of race” paper but in the meantime id like argue the need to elimate or include all possible variables be they genetic or enviromental in any research regarding human IQ or any issue dealing with human mental oe physical statistics. I would also like to point out two studies in paticular that point to the extreme negative effects of racism on Afro Americans mentally & genetically & allude again to the HMGA C alles variation that leads to low IQ.
      One is a study of the high rate of miscarriage in Afro American women & 2nd generation female African immigrants. The miscarriage rate of recent female African immigrants is equal to female White Americans so the question is what causes Afro American women to miscarry at such a high rate. It apparently is tied to being raised & living in America. The primary genetic culprits have been eliminated so what we are left with is psycho social & socio-environmental factors racism being the primary suspect. Racism or precieved racism causes stress levels to rise.

      http://www.scientificamerican.com/article/stillbirth-risk-factors/

      My view is that if environment can effect birth rates it obviously can effect ones academic peformance & IQ. As an Afro American I know this but as an academic I must of course offer data that scientifically supports this theory

      The other study id like to allude to is the recent discovery that memories can be passed down via genes. The historic trauma of slavery has long been theorized to be genetically ingrained in Afro Americans. This recent research seems to support this theory as fact.

      http://m.bbc.com/news/health-25156510

      This being factual one has to consider this data in any research that hopes to be accurate concerning IQ.

      Lastly id like to simply point out that the gene recently discovered to be linked to skull size & IQ (HMGA2) has a C allele variation that apparently caused smaller skull size & lower IQ. This genetic variation has not been found to be ubiquitous amongst Afro Americans in fact its been found that Africans have one of the higher rates of the C allele of rs10784502 which to qoute

      “is associated, on average, with 9,006.7 mm3 larger intracranial volume, or 0.58% of intracranial volume per risk allele and is weakly associated with increased general intelligence by approximately 1.29 IQ points per allele.
      (ill soon place the population distribution HapMap on my blog)
      These genetics refute any assumption that lower African IQ is inherently genetic in causation & unique to the race.
      As ive stated the generally larger skull & eye ball size of Caucasians & Mongoloids is an adaptation to darker over cast climates. Genetic variations such as the C allele variation is not the cause for smaller skull size amongst tropical people thus cannot be the cause for lower IQ.
      The skull size of African generally is the original skull size of Europeans & Asians prior their adaptation to their new habitat. This means the European & Asian skull & eye ball size is a mutation from the original archtypical Africoid phenotype As you know a variation in an allele is a mutation so concluding the smaller skull size & lower IQ amongst tropical people is connected with these recent findings concerning HMGA2 would be seriously flawed genetics.

      • Chuck
        March 23, 2014 at 9:36 pm

        Dear hucipher,

        As for your comments, I do not judge that a genetic account of the reproductive casualty rate differences has been ruled out. See, for example, here:

        Anum, E. A., Springel, E. H., Shriver, M. D., & Strauss, J. F. (2009). Genetic contributions to disparities in preterm birth. Pediatric research, 65(1), 1-9.

        http://www.nature.com/pr/journal/v65/n1/abs/pr20091a.html

        It is probable the Black Africans are not much more genetically predisposed to higher rates of miscarriages than are White Europeans, but this situation does not preclude involvement of genetic factors regarding differences between White Americans and Black Americans. With regards to non-human animals, it has often been found that the likelihood of reproductive casualty varies as a function of the genetic distance between ancestral populations. That is, there is what is called outbreeding depression. It so happens that second generation plus African Americans are substantially more genetically heterogeneous than are European Americans, making plausible an outbreeding depression hypothesis. The results discussed by Anum et al. (2009) largely support this position. So, no, the primary genetic culprits have not been eliminated.

        Regarding physical environmental factors and the African (Black)-European (White) American psychometric intelligence differences, refer to my discussion in section F here. These types of factors (e.g., lead poisoning and access to health care) can only statistically — which is not necessarily to say causally — explain a small portion of the differential. Regarding epigenetics, there are numerous problems which such an account. For one, while it has been established that genes explain a large portion of variance within populations, no one has every shown that epigenetic factors account for any such variance — and if epigenetic factors were acting between populations, one would expect them to act within. To note, epigenetic effects would show up as shared environmental influences — influences shared by siblings — yet shared environmental influences explain little within populations variance in intelligence. As such, it is necessarily the case that epigenic factors can have little effect, if any at all, on intelligence. On request, I will provide a more elaborate explanation for why epigenetics is an awful explanation.

        Now, you say: “These genetics refute any assumption that lower African IQ is inherently genetic in causation & unique to the race.”

        See here for an analysis which took into account more alleles: “Simple statistical tools to detect signals of recent polygenic selection”. I agree, though, that this issue will largely be settled by IQ allele counting — probably within a year or two. My point is that it could have — and should have — already been settled e.g., by using admixture mapping. Do you disagree with me on this point?

      • March 24, 2014 at 4:08 am

        I agree Alelle testing & counting may help give us more conclusive results. Any genes must be identified then proven to be more or less prevelant with in racial phenotypes. As for the HMGA2 c-allele I feel it has been adequately ruled out as a culprit in concerns of the low mean IQ of Afro Americans. In my opinion the studies supporting race based IQ disparities are speculative at best. Also I would argue European Americans are far more heterogeneous than Afro Americans. Due to color classism Whites strived to remain genetically “pure” regarding thier mixed offspring as Black or anything other than White. Due to this same classism Blacks placed a high regard on “mixed” blood. Blacks historically where forcibly micegenated with the White slave masters & interbreed of their own free will with poor Whites, Amer-Indians & even Chinese immigrants. Afro Americans are a highly genetically jumbled bunch. im not sure admixture mapping will help until more genes that definitely effect IQ are discovered. So far Ive seen studies that look at the same genetic data but arrive at different conclusions. When it comes to things dealing with mental health & aptitude I would say enviromental stimuli must always be factored in & the case of Afro Americans the case of active discrimination from the out side society is to well documented to dismiss. In my opinion determining the genetic components in this era will always be contaminated by enviromental effects.

  1. April 15, 2013 at 10:31 pm

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