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Genetic groups in the modern world

  1. Feb 14, 2004 #1


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    There's been some interesting discussions in this sub-forum on IQ, intelligence, the g Factor, races, hereditability, a nation's wealth, eugenics, and other things.

    One thing I found particularly interesting in this discussion is the work of Cavalli-Sforza into pre-1492 population groups and the genetic distance between them (although I haven't found an answer to the question why the largest population group on Earth - the Han Chinese - don't appear in the list of 42 population groups).

    Since 1492, the 5,000 km limit (Jensen? hitssquad posted it, but I can't find it just now) for a race (Jensen) or group (Cavalli-Sforza) has become a whole lot less important. Indeed, according to Lynn and Vanhanen (and the authors they quote), the following 'races' are to be found in Africa:
    - Colored
    - Creole (black-white hybrids)
    - Mixed black-white

    and in the US, "blacks" are in fact comprised of groups whose "white" ancestry ranges from ~4-10% to >40% (Jensen).

    The US Census Bureau gives population estimates for the following 'races':
    - White
    - Black or African American
    - American Indian and Alaska Native
    - Asian
    - Native Hawaiian and Other Pacific Islander
    - Some other race

    In 2000, ~2.4% of those surveyed 'reported more than one race'

    Regarding Hispanics, the Bureau said: "The Census Bureau also reported that Hispanics, who may be of any race, totaled 35.3 million, or about 13 percent of the total population."

    Since 1994 (when Cavalli-Sforza et al published the results of their study, including the genetic distance tree and 1st PC vs 2nd PC plane) our ability to determine genetic difference between individuals has improved dramatically.

    What does a 1st PC vs 2nd PC plot of residents of the US look like now?

    How different is the "English" population group in Cavalli-Sforza's tree from today's inhabitants of the England?

    Where in Cavalli-Sforza's tree do African Americans, Creoles, coloreds, and Hispanics fit?
  2. jcsd
  3. Feb 19, 2004 #2


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    'Black' and 'White' - inconsistent definitions?

    As hitssquad, Apollo, Carlos, and Nachtwolf have not, so far, posted any replies to this thread, I went looking for answers myself.

    Here's a site which I found very interesting (the link is to one article which I will discuss further): http://psycprints.ecs.soton.ac.uk/archive/00000699/

    Although Paul Jorion (the author of the article linked above) may be a little shrill, and some of the points he makes a little overstated, he neatly summarised an inconsistency which I noticed (but he describes it better than my woolly thinking), and which seems a significant flaw in the racist case.

    *SNIP "2. The test groups are defined as "persons of European ancestry who are socially identified as 'white' and persons of some African ancestry who are socially identified as 'black' or African-American" (p. 350). Notice the use of "some" in the previous sentence. The cultural basis of this so-called "social identification" is immediately apparent when one realises how differently the sentence would read if the "social definitions" for white and black were simply reversed, and the test populations defined as "persons of African ancestry who are socially identified as 'black' and persons of some European ancestry who are socially identified as 'white'". The statistical flaw that mars the entire research becomes even clearer when the author states that

    all of the descriptive statistics and studies referred to here are based on the social classification of individuals into racial groups as black and white, although virtually all American blacks have some degree of European Caucasian ancestry. American blacks are socially defined simply as persons who have some degree of sub-Saharan African ancestry and who identify themselves (or, in the case of children, are defined by their parents) as black or African American. Persons of European Caucasoid ancestry are classified as whites." (p. 353)

    Notice how this classification supposedly rests entirely on how "
    persons who have some degree of sub-Saharan African ancestry [...] identify themselves" and how black children depend on their parents' "definition" to be regarded as such. Let us analyse carefully how such a crucial flaw has developed. Since Jensen is a fastidious methodologist I will need no further support than what is to be found in his own writings. Here, in the author's own terms, is an account of the "wrong conception of race":

    The root of most wrong conceptions of race is the Platonic view of human races as distinct types, that is, discrete, mutually exclusive categories. According to this view, any observed variation among the members of a particular racial category merely represents individual deviations from the archetype, or ideal type, for that 'race'". (p. 421)

    The accurate conception he subsumes under the heading of "Races as Breeding Populations with Fuzzy Boundaries", and insofar as the white-black or black-white continuum is concerned, provides some figures on "
    the proportion of Caucasoid genes [in] the black gene pool" (p. 432), such as: "M [intermixing index; FOOTNOTE 1] varies across different regions of the United States, being as low as 4 percent to 10 percent in some southeastern States and spreading out in a fan-shaped gradient toward the north and the west to reach over 40 percent in some northeastern and northwestern states" (ibid).

    3. How do these two conceptions of race, the false and the true, apply to the test populations of black and white? The definition of black derives from the accurate view of a "breeding population with fuzzy boundaries", as it regards as black anyone with "some African ancestry". The definition for white however derives from the wrongheaded one of "
    human races as distinct types, that is, discrete, mutually exclusive categories". Jensen writes that "persons of European Caucasoid ancestry are classified as whites", but this he understands as a necessary condition, not as a sufficient one: indeed if such persons can at the same time trace any amount of African ancestry, they cease automatically to be white and become black. It is clear that as much as he regards being black as being located on a spectrum, being white rests in his mind on an all-or-nothing condition, i.e., exactly what his "wrong conception of race" assumes. What invalidates Jensen's testing of his hypothesis is not so much that for his two sample populations he sometimes relies on an accurate definition of race, sometimes on an inaccurate one, but that their definition depends on two separate senses of the same word.
    Last edited: Feb 19, 2004
  4. Feb 19, 2004 #3
    Re: 'Black' and 'White' - inconsistent definitions?

    Actually, Jensen wrote:

    • Gene flow, of course, goes in both directions. In every generation there has been a small percentage of persons who have some African ancestry but whose ancestry is predominantly Caucasian and who permanently "pass as white." The white American gene pool therefore contains some genes that can be traced to Africans who were brought over as slaves (estimated by analyses of genetic polymorphisms to be less than 1 percent). (Reed T. E. ( 1969a). "Caucasian genes in American Negroes". Science, 165, 762-768.)

    For the puposes of Jensen's study of American blacks and whites in relation to the g factor and the g nexus, whites are persons who have some caucasoid ancestry and self-identify as whites, and blacks are persons who have some negroid ancestry and self-identify as blacks.

    One simple explanation for why there might appear to be a double standard in Jensen's definition -- e.g., necessity of self-identification is not made explicit in the definition of white, and the possibility of presence of negroid genes in a population group identified as white is not always made explicit -- is that nature has provided a double standard. Viz, Americans who have been self-identifying as black have tended to be far more caucasoid than people who have been self-identifying as white have tended to be negroid.

    As the present author noted recently in a similar post on this topic, one of the latest reports on gene-pool distribution indicates Jensen's estimate of 25% caucasoid genes in the self-identified-as-black gene pool is high by about 8%. However, Jensen's estimate of less than 1% negroid genes in the self-identified-as-white gene pool is sustained in that latest report:

    • Among self-identified whites in Shriver's sample, the average black admixture is only 0.7 percent. That's the equivalent of having among your 128 great-great-great-great-great-grandparents (who lived around two centuries ago), 127 whites and one black.

      It appears that 70 percent of whites have no African ancestors. Among the 30 percent who do, the black admixture is around 2.3 percent, which would be like having about three black ancestors out of those 128.

      In contrast, African-Americans are much more racially mixed than European-Americans.

    Again, nature seems to have provided a genetic-mixing double standard -- a contrast between the genetic admixture distribution in self-identified whites vs. that in self-identified blacks. Jensen as a reporter of such a double standard is not necessarily blameful for it.
    Last edited: May 12, 2004
  5. Feb 20, 2004 #4


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    So, in his research, Jensen used the race which his (and colleagues') subjects reported (and reported for their children). Further, they (Jensen et al) selected only those who self-reported 'black' or 'white'.
    Finally, they sought to establish the g nexus through statistical analysis of group data. I appreciate that this is an oversimplification, but I'm trying to find out just how the 'race-g' relationship was established.

    A hundred questions arise then; e.g.
    - were subjects able to report 'both black and white' as their race? If so, how was the data from such subjects treated during analysis?
    - seeing as how in the US Census Bureau says that Hispanics may be of any race, how was data from subjects who said they were 'Hispanic' (or similar) treated?
    - similar questions about 'Asian', 'American Indian' and 'Alaska Native', 'Native Hawaiian and Other Pacific Islander', 'some other race'
    - "approximately 30% of Americans who consider themselves 'white' have less than 90% European ancestry." (M. J. Bamshad and S. E. Olson, "Does Race Exist?", Scientific American (December 2003), quoting results from a study by Shriver and Kittles. From hitssquad's quote, the >10% isn't all African; what is it?
    - since both 'blacks' and 'whites' are racially mixed groups, to what extent did Jensen et al attempt to show a g factor cline within the two groups?
    - in identifying the clines, to what extent did they make it come out of the data (cf specifically looking for correlations they wished to find)?
    - naively I would expect that, if g had high hereditability and a racial basis, the distributions of sample data about the sample means would be non-Gaussian, and the measures of variation about the means (standard deviations in particular) telling all kinds of interesting stories. If nothing else, the means and medians would rarely coincide, and the mean-median differences show high statistical significance. What do the distributions look like?
    - if, in fact, Jensen was so careful with his statistics, and if the 'blacks' and 'whites' are clearly NOT races, was it Jensen who made the g-race link? How was that link made?
    - what is the relevance of the Cavalli-Sforza population groups to US studies of g (seeing as how the only such groups native to the US - presumably N Amerind and NW American - were neither studied nor likely to be 'races' today)?
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