March 23, 2012

African American athletes have more European mtDNA than the general AA population

Does anyone have a theory why this is the case?

American Journal of Physical Anthropology DOI: 10.1111/j.1600-0838.2010.01289.x

Importance of mitochondrial haplotypes and maternal lineage in sprint performance among individuals of West African ancestry

M. Deason et al.

Mitochondrial DNA (mtDNA) is inherited solely along the matriline, giving insight into both ancestry and prehistory. Individuals of sub-Saharan ancestry are overrepresented in sprint athletics, suggesting a genetic advantage. The purpose of this study was to compare the mtDNA haplogroup data of elite groups of Jamaican and African-American sprinters against respective controls to assess any differences in maternal lineage. The first hypervariable region of mtDNA was haplogrouped in elite Jamaican athletes (N=107) and Jamaican controls (N=293), and elite African-American athletes (N=119) and African-American controls (N=1148). Exact tests of total population differentiation were performed on total haplogroup frequencies. The frequency of non-sub-Saharan haplogroups in Jamaican athletes and Jamaican controls was similar (1.87% and 1.71%, respectively) and lower than that of African-American athletes and African-American controls (21.01% and 8.19%, respectively). There was no significant difference in total haplogroup frequencies between Jamaican athletes and Jamaican controls (P=0.551 ± 0.005); however, there was a highly significant difference between African-American athletes and African-American controls (P less than 0.001). The finding of statistically similar mtDNA haplogroup distributions in Jamaican athletes and Jamaican controls suggests that elite Jamaican sprinters are derived from the same source population and there is neither population stratification nor isolation for sprint performance. The significant difference between African-American sprinters and African-American controls suggests that the maternal admixture may play a role in sprint performance.

Link

20 comments:

  1. It likely damakes them taller, bigger, more robust.

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  2. It may be interpreted as a direct observation of hybrid vigor in humans. Although other explanations are possible.

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  3. I'd say, let's first see the autosomes. Autosomal results can be quite different from haplogroup results.

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  4. Where in the world is the genomic control? How do they know the African component in the ancestry of the sprint athletes?
    Shouldn't they only include African Americans with similar amounts of non-African ancestry?
    What about socio-economic status?

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  5. Sexual selection?
    At a time when AAs were enslaved and/or discriminated against, those who had the best probability of mating with white females of the privileged class were those considered to be healthiest/most attractive/physically fittest. Their mixed offspring would simply have inherited those characteristics.

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  6. Lol, and people tought that blacks were inherently better at sports that involded sprinting and jumping. I wouldn't have tought of this either.

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  7. Obviously, in my previous comment I was referring to the deepest point in time when European mtDNA could have been introduced into AA populations. If the admixture is very recent, sexual selection may still work to an extent, but extreme selective factors related to segregation/enslavement would be out of the picture, of course.

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  8. Before claiming biological reasons, I would first check if the same systematic difference can be found in the college vs. non-college populations, the former of which top athletes such as sprinters are trained in, in the US. Perhaps, families with Caucasian mothers in their lineage have a socio-economic advantage that leads to a lower high-school drop-out rate, and higher college participation (that socio-economic advantage in itself is hugely correlated with college education in the US).

    I doubt long-distance runners from Ethiopia and Kenya have non-African mtDNA, and they seem to be doing just fine.

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  9. ''I doubt long-distance runners from Ethiopia and Kenya have non-African mtDNA, and they seem to be doing just fine.''

    Approximately half of the general Ethiopian mtDNA genepool are Eurasian back-migrant lineages (N/M). Many Kenyan groups also have some of this, while it is absent in South-Central Africa.

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  10. In the US lighter skinned African-Americans have more educational advantages and hence more opportunities to participate in sports. In Jamaica, an all Afro-Caribbean society, light skinned people may not have this relative advantage.

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  11. Has anyone made a specific list of these non-recent-African MtDNA lineages? More and more statistical correlations are emerging between MtDNA lineage and a host.of genetic (or more properly, epigenetic) predispositions, including athletic abilities. Granted, a recent study of MtDNA among elite Ethiopian athletes shows no such correlation. Here's that link: http://www.ncbi.nlm.nih.gov/pubmed/15694598. On the other hand, such a correlation seems to exist among Japanese athletes. Here's that link: http://bjsm.bmj.com/content/45/15/1179.abstract
    Sorry, I haven't mastered hyperlinking yet. Perhaps my 3.1% Neanderthal background is to blame? :–P

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  12. @Charles said
    In Jamaica, an all Afro-Caribbean society

    That's not correct, Jamaica is majority Afro-Caribbean, but not exclusively so. I like most Irish people have relatives in Jamaica, who are of partly European descent.

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  13. There is no doubt that Jamaicans are fast, but if you look at their female sprinters, most came out of relative obscurity to do a medals sweep in the last Olympics, I rate this as highly suspicious, as it seems too like the East German women sprinters of a few decades ago. So I think widespread doping of male and female sprinters can't be ruled out in Jamaica.

    In terms of the correlation of some European ancestry with speed, I had noticed that but don't think it can be directly related to mtDNA. As mtDNA controls Aerobic Respiration - which is important to muscle performance - but for sprinters, where a burst of great speed is involved, ANaerobic respiration becomes important, so if anything I'd say some factor linked to this might be selected for.

    I also note 2 things:

    1. The country supposedly contributing the most European DNA to African-Americans is Ireland. The fastest White man in the world is Native Irish - Paul Hession - from Galway in the West of Ireland:

    http://en.wikipedia.org/wiki/Paul_Hession

    2. If we look at another species of sprinter - Thoroughbred racehorses - we find that their speed is derived from Shetland or Galloway Ponies. As introgression from these ponies from Scotland introduced the "speed gene C-type myostatin" to Thoroughbred racehorses:

    http://www.irishexaminer.com/breakingnews/sport/irish-scientist-traces-racehorse-speed-to-ponies-537143.html

    So there is a precedent for this type of supposed anomaly.

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    1. Jamaica sprinters may seem to come out of obscurity internationaly, but most with the exception of Asafa Powell who was a football player in high school, are seasoned track athletes running in championships before high school. There are Primary Championships, Prep championships, All Age championships and High School championships.

      My belief is that it is less the NDA, less the food and more the conditioning of the body over years (through the developmental stages) that makes Jamaica athletes so successful.

      Jamaica has the Sparta of printing to find the talent among its population... Kenya and Ethiopia have similar for distance running.

      Another factor in winning so many medals at the last Olympics was confidence. This confidence came from the presence of Bolt in the camp and was different from previous Olympics where our Athletes were beaten at the start line by US athletes who were more confident and sadly for the sport may have been on drugs. With a champion like bolt and the support if the crowd, Jamaica may be benefiting from a sort of home crowd advantage.

      Since the balco scandal, the US athletes seem more human, and the Jamaican athletes are now able to compete on level playing field.


      Visit Jamaica and see for yourself, there are quite a few of your countrymen there.

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  14. ^ Yes, didn't you say at some point, that there was slavery of Irish before they brought the Africans?

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  15. University of the West Indies gives the following breakdown:

    76.3% African descent, 15.1% Afro-European, 3.4% East Indian and Afro-East Indian, 3.2% Caucasian, 1.2% Chinese and 0.8% Other.

    http://www.uwi.edu/territories/jamaica.aspx

    It would be interesting to see an autosomal study comparing Jamaicans and African Americans.

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  16. Jamaica is a much less racist society than the USA. Black Power hit Jamaica hard and although some of the richer folk are paler black is beautiful in Jamaica.

    The educational system is modelled on the British system so this college team business has no impact at all. All the best schools were in the state sector (free entry by an 11 plus examination, in my day).

    Jamaicans if anything is one of the blackest Caribbean islands although it has substantial European, Lebanese and Chinese input (and probably Arawak). But Jamaicans IMO have always had a tendency to Amazonian health and build which I always assumed reflected the specific tribes taken there. Particularly folk who claimed Maroon stock. http://en.wikipedia.org/wiki/Jamaican_Maroons

    A lot of early African American athletes seemed to be of Jamaican origin as Jamaica tended to reclaim them when the Olympics were on.

    Perhaps the children of white women were more likely to move on to the USA. But to me it looks like the white mothers having a significant positive effect on the attitudes and ambitions of their descendants living in a racist environment. Obama being the perfect example.

    West Indians in general used to do better in the USA when they first arrived, something that used to cause resentment between African Americans and West Indians at one time. Attitude overcomes.

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  17. @AnnieMouse,

    I've no doubt that the Jamaican Maroons are a hardy bunch. However in terms of speed, where are the West Africans FROM AFRICA, who are as fast or faster than Afro-Caribbeans or African-Americans, the answer seems to be that there are few/none. It's interesting that they use words from the Akan language of West Africa. Another group of Afro-Caribbeans, who were also descendant from Akan speakers are of course the Haitians, who are almost exclusively descended from slaves from Dahomey (aka Benin), next to Ghana. They rose up against their owners in the late 1700's and largely exterminated them. So they are on average much more African than Jamaicans, and AFAIK haven't produced any outstanding sprinters.

    Whereas the Moroccan, Ethiopian and especially Kenyan, endurance runners FROM AFRICA are everywhere in sports.

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  18. The Dahomean language, Fon is a Gbe language, not Akan. Ewe, Gen and Aja are also Gbe. There were few Akan in Haiti. Also, there is often a substantial common element in new world Blacks, including Haitians and Jamaicans, of Kongo/Angolan Mbun and related Western Bantu.

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  19. @ pconroy

    Christophe Lemaitre of France has now bested Paul Hession with 1000 and 200 meter times of 9.92 seconds and 19.80 seconds respectively.

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