Evolutionary Cognitivism, Part II: Epigenetics and Diversity

The question of group-level human variation has been a hot one. Some research argues for continental, race-like groupings in which there is more variation between groups than within them (Jorde, et al., 2000) and that self-identified race is a reliable predictor for one’s genetic heritage Tang, et al,, 2005). Other research suggests while there is group-level genetic variation, it exists within a gradation of populations and not a small number of historically isolate draces (Serre & Paabo, 2004). While it is increasingly recognized that early scientific research, such as Lewtonin 1970, which denied any meaningful group-level variation was overly simplistic (Edwards, 2003). Though studies which look at only a few phenotypes continue to find little intergroup variation (Relethford, 2002), broad studies find definite intergroup variation (Rosenberg, 2005) and intragroup similarity (Rosenberg, et al., 2006) Several portions of Bjorklund & Pellegrini’s (2002) third chapter, History and Controversy, also hint at ways that human groups could be more different from each other than once thought.

One way that biological group level variation can increase is if experience can somehow be paseed from parent to child. For instance, even if two populations are genetically very similar, if they face different environments, and the effects of the environment can be passed down, you could have biologically-based differences in only one generation. This was once considered anathema to modern biology: Bjorklund & Pellegrini write that “Inheritance, and thus genetic variation, is found only within the germ line and is not influenced by experience” (47). However, i tis now recognized that “physical” and “behavioral” changes can be passed on (53). An early example of this was Jean Piaget’s experiment with epigenetic snails (54). In contemporary jargon, we should say that “females pass on cytoplasm (i.e., the cell body) to their offspring [and so environmental] changes that induce chemical changes in the cytoplasm can thus be inherited through the motehr but not through the father” (56). On the same page, the authors note that while this cytoplasm is not itself genetic, “Cytoplasmic inheritance should not be thought of as nongenetic [because] it necessarily expressed its effect on the genes.”

It’s relatively easy to imagine how this could work. Imagine two otherwise similar populations which are divided from each other. This division forces both to become relatively self-contained breeding populations and leads to differences in diet, with one population eating nutritious food and the other near starvation. After just a few generations, cytoplasmic variants adept to surviving and reproducing in starvation-conditions could become very widespread in the one population, while an opposite set of cytoplasmic variants become widespread in the other population. Frighteningly, this may be happening in Korea. The height difference between North and South Koreans is already four inches (Ser & Team, 2006). If some of this difference is epigenetically, cytoplasmically inherited, this could create a de-facto “racial” divide among Koreans that might last centuries, even after a return to environmental equality.

Non-coding DNA is another thing that may have led to a discounting of human intergroup genetic diversity. Bjorklund & Pellegrini describe this DNA as “dormant” and “underused” (57). However, the 97% of our genome that is intergenetic “can have dramatic effects on the way that nearby genes are activated to make proteins” (Pinker, 2002, 78). One such piece of junk DNA, Dopamine Receptor D4 7 Repeat – has been tied to ADD and novely seeking (Laucht, Becker, & Schmidt, 2006). As earlier studies of human differences focused on coding DNA, such as protein loci and blood group loci (Latter, 1980), these studies have essentially just ignored 97% of human genetic difference. This is especially sad as junk DNA can be inserted into RNA, thus becoming functional (Lev-Maor, Sorek, Shomron, & Ast, 2003).

Yet the idea of intergroup genetic diversity among homo sapiens causes controversy. Indeed, the idea that genes matter in the human species causes controversy Richard Lewtonin, whose work denying the existence of races was cited earlier, famous accused E.O. Wilson of mirroring “the ideologies of the bourgeois revolutions of the eighteenth century” (Ridley, 2003, 243). How much more disturbing it might be if not only do children already know about “language… objects… and social relations” (Bjoklund & Pellegrini, 2002, 61), but that groups of children vary in their knowledge of these objects. For instance, if one group has a higher general intelligence ability while another group as a higher rythmatic intelligence (Lynn, 2006). Does this imply that one genetic grouping is more valuable than another?

The answer, of course, is no. As Steven Pinker (2002, 145) wrote “The case against bigotry is not a factual claim that humans are biologically indistinguishable. It is a moral stance…” We are all equally human. We are all equally valuable. No evidence, ever, could change that.

Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Ding, Y., et al. (2002). Evidence of positive selection acting at the human dopamine receptor D4 gene locus. PNAS, 99(1) 309-314.
Edwards, A.W.F. (2003). Human genetic diversity: Lewtonin’s fallacy. BioEssays 25(8): 798-801.
Jorde, L.B., Watkins, W.S., Bamshad, M.J. Dixon, M.E., Ricker, C.E., Seielstad, M.T., & Batzer, M.A. (2000). The Distribution of Human Genetic Diversity: A Comparison of Mitochondrial, Autosomal, and Y-Chromosome Data. American Journal of Human Genetics
Latter, B.D.H. (1980). Genetic differences within and between populations of the major human subgroups. The American Naturalist 116(2): 220-237.
Laucht, M., Becker, K., & Schmidt, M.H. (2006). Visual exploratory behaviour in infancy and novelty seeking in adolescence: two developmentally specific phenotypes of DRD4?. Journal of Child Psychology and Pschiatry 47(11): 1143-1151.
Lev-Maor, G., Sorek, R., Shomron, N., & Ast, G. (2003). The birth of an alternatively spliced exon: 3` splice-site selection in Alu exons. Science 300(5623): 1288-1291.
Lewontin RC. The Genetic Basis of Evolutionary Change. New York: Columbia University Press. 1974.
Lynn, R. (2006). Race differences in intelligence: An evolutionary analysis. Washington Summit Publishers: New York:
Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. Viking Adult: New York, NY.
Relethford, J.H. (2002). Apportionment of global human genetic diversity based on craniometrics and skin color. American Journal of Physical Anthropology 118(4): 393-398.
Ridley, M. (2003). Nature via Nurture. Harper Collins: New York, NY.
Rosenberg NA, Mahajan S, Ramachandran S, Zhao C, Pritchard JK, et al. (2005) Clines, Clusters, and the Effect of Study Design on the Inference of Human Population Structure. PLoS Genet 1(6): e70 doi:10.1371/journal.pgen.0010070
Rosenberg NA, Mahajan S, Gonzalez-Quevedo C, Blum MGB, Nino-Rosales L, et al. (2006) Low Levels of Genetic Divergence across Geographically and Linguistically Diverse Populations from India. PLoS Genet 2(12): e215 doi:10.1371/journal.pgen.0020215
Ser, Myo-ja & Team. At the DMZ, average height changes 4 inches. JonhAng Daily. November 21, 2006. Available online: http://joongangdaily.joins.com/200611/20/200611202311326539900090409041.html.
Serre, D. & Paabo, S. Evidence for gradients of human genetic diversity within and among continents. Genome Research 14:1679-1685.
Tang H, Quertermous T, Rodriguez B, Kardia SL, Zhu X, Brown A, Pankow JS, Province MA, Hunt SC, Boerwinkle E, Schork NJ, Risch NJ (2005) Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies. Am J Hum Genet 76:268–275

Evolutionary Cognitivism, a tdaxp series
1. Selection and Cognition
2. Epigentics and Diversity
3. Children and Civilization
4. The Implicit and the Explicit
5. Man Among Men
6. More Than Genes
7. Bibliography

10 thoughts on “Evolutionary Cognitivism, Part II: Epigenetics and Diversity”

  1. Dan,

    I'm a bit lost on the term “rythmatic intelligence.” Cognitive trial and error? Would you define?


    As science increasingly explores genetic diversity among humans (I should think this is a big part of understanding human kind in both the genetic and behavioral sense) will it come under further fire from a “moral outrage” and can science effectively mitigate popular morality in it's own best interest?

  2. Subadei,

    Really I was just having with with sense of rhythm as a one of the multiple intelligence. There's been some discussion on this [1,2] and it would be interesting if some people — and some groups of people — are genetically predisposed to have better rhythm than others.

    My question was rhetorical, and asked wheter a group with (statistically) a better sense of rhythm would be less valuable than a group with (statistically) a better sense of writing. My answer is no. All humans are created equally valuable. This is not a factual question. This is a moral certainty.

    (Thanks for catching this. I reworded that section in the original paper.)

    As for science…

    Sociobiologists and Evolutionary Psychologists, who argue for a genetic basis for the psychic unity of man, have been called reactionaries, Nazis, and the like by the Left. [3] They argued that there was only a universal human race (sometimes called “homo sapiens sapiens”) with a universal human nature, and they were called racists! The Left jumped the shark a long time ago.

    “can science effectively mitigate popular morality in it's own best interest?”

    In what ways are you thinking?

    [1] http://www.gnxp.com/blog/2006/11/kuffar-vs-muslim-rappers.php
    [2] http://akinokure.blogspot.com/2006/07/group-differences-in-cognitive-profile.html
    [3] http://www.tdaxp.com/archive/2006/06/17/leftist-censorship-and-the-nature-of-modularity.html

  3. “”the ideologies of the bourgeois revolutions of the eighteenth century”

    In my experience, folks who say things like that as an accusation, are are usually either ignoramuses with a veneer of education untouched by deep thought or are well educated but malevolent.

  4. Nothing has taught be the difference between liberalism and leftism better than studying under liberals so despised by leftists.

    Relatedly, a notable research (I won't say who, but here's his paper [1]) mentioned to me a while ago, “Outside of academia, America has liberals but no leftists, conservatives but no rightists. This how American politics differs from European politics. This is why American's can't understand Europe, and Europeans can't understand America.”

    I thought it was a pretty clever thought.

    [1] http://digitalcommons.unl.edu/politicalsciencehendricks/4/

  5. In what ways are you thinking?

    This is off the cuff, but:

    A stronger and more direct political presence. Domestic politics has essentially devolved into a quagmire of strict idealism. I think Americans would welcome leaders whose proclivities run a lot less poli and a little more sci. Imagine the late Carl Sagan as a senator.

    That's a start, anyway.

  6. Subadei,

    “I think Americans would welcome leaders whose proclivities run a lot less poli and a little more sci.”

    Americans would welcome pretty much any leader who was a little less poli. [1] So I'm sure people would welcome the idea of a technocratic government. The problem with that perspective is that politicians are quiet good at getting themselves elected. After all, it's what they do. 🙂

    [1] http://www.parapundit.com/archives/000935.html

  7. “I think Americans would welcome leaders whose proclivities run a lot less poli and a little more sci. Imagine the late Carl Sagan as a senator.”

    Certainly we need more politicians who have real world careers and experience who go into politics for a temporary period of time and then return to the real world, including scientists. But any idea that scientists by virtue of being scientists have any special competence to make political decisions is ridiculous.

  8. phil,

    In regards to your context I agree. But the context I provide wasn't to somehow validate scientists as more competent in political practice or decision making. Further, I'm not advocating a technocracy by any means.
    The matter at hand was “”can science effectively mitigate popular morality in it's own best interest?” To which Dan offered “In what ways are you thinking?”

    My position isn't that scientists should dominate our govenment rather that the presence of more scientific minds (as opposed to lawyers) within our govenment might mitigate some of the more negative public rhetoric regarding certain scientific exploration.

  9. subadei,

    Oops, I misunderstood what you were saying, my mistake. I agree with you that true science should prevail over political rhetoric in relevant issues. Unfortunately that won't happen as long as long as it is generally accepted that government can regulate anything. Modern civilization is characterized by the establishment of boundaries. Boundaries drawn among religion, politics, science; between government and civil society, and so on. Like the jungle reclaiming cities and cultivated land, the breaking down of boundaries is the dissolution of civilization. In order to mitigate the political rhetoric with regard scientific issues there needs to be a clear understanding of and support for the boundary between politics and science.

  10. Perhaps there are two related questions here:

    1. Would it be better if congressmen were skilled in the subject matters they deal with, and
    2. Would it be better if congressmen were term limited, and thus forced to have serious outside careers

    I don't know, but considering how congress is a power-brokering and not welfare-maximizing agency, it might be best to keep them away from technical competence. (China's government of engineers works, I imagine, because they do not have the same sort of public accountability as Congress does.)

    I think congressional term limits would be an admiable goal.

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