Elsevier

Medical Hypotheses

Volume 77, Issue 6, December 2011, Pages 1121-1124
Medical Hypotheses

Historical determinants of contemporary attributes of African descendants in the Americas: The androgen receptor holds the key

https://doi.org/10.1016/j.mehy.2011.09.017Get rights and content

Abstract

It is hypothesised that seemingly disparate and unrelated phenomena clustering in persons of African descent living in the Americas such as outstanding sprinting ability and high prostate cancer incidence and mortality are in fact related and emerge from enhanced testosterone responsiveness in descendants of African slaves surviving the transatlantic trade in Africans. It is postulated that the ability to have survived the middle passage was positively correlated with greater responsiveness of the androgen receptor to its primary ligands dihydrotestosterone and testosterone, and that slaves possessing more responsive androgen receptors experienced a survival advantage engendered by the enhanced anabolic effects which accrued such as increased red cell mass and therefore greater oxygen carrying capacity and tissue oxygen delivery enabling these slaves to tolerate stifling conditions in the hull of the slave ship, increased lean muscle mass and therefore greater surface area to volume ratio resulting in easier ability to dissipate heat and remain cool, and increased skin thickness and sebum production resisting the macerating effect of lying in admixed bodily fluids below deck. These androgen effects as well as others would have produced a survival advantage under the severe selection pressure created by the inhumane and physiologically challenging circumstances under which the slaves were transported from the interior of the African continent and West Africa to the ‘New World’. This would result in a population shift favouring increased androgen receptor responsiveness in descendants of African slaves populating the Americas and a corresponding geographic and racial distribution of androgen related phenomena such as sprinting prowess and prostate cancer. African-Americans having the highest prostate cancer incidence rate and the Caribbean having the highest prostate cancer mortality rates in the world are consistent with this hypothesis as is the observation that the 10 fastest men and 9 fastest women of all time are exclusively the descendants of West African slaves who survived the middle passage. It is predicted that as yet undiscovered as well as known biological correlates of enhanced androgen receptor responsiveness such as relatively short CAG-repeats in the poly Q tail of exon 1 of the androgen receptor gene will be more prevalent among African-Americans and Afro-Caribbean peoples than among West Africans. It is also predicted that African-Americans and Afro-Caribbean peoples will have relatively shorter CAG-repeats in the androgen receptor gene compared to West Africans.

Introduction

The clustering of seemingly disparate phenomena such as sprinting prowess and prostate cancer among persons of African descent from the Caribbean and the USA while there is no clustering of such phenomena in Africans born and residing in Africa is intriguing and deserving of academic investigation and analysis. The 10 all-time fastest men in the world over 100 m and 9 all-time fastest women, based on the International Association of Athletics Federations’ statistics, are from the Caribbean and the USA [1]. African-Americans have the highest incidence of prostate cancer in the world while the Caribbean has the highest prostate cancer mortality [2]. It is known that athletic sprinting performance is enhanced by the illicit use of anabolic steroids [3] and that treatment – naïve prostate cancer is an androgen dependent tumour which thrives in the presence of testosterone and involutes when testosterone is withdrawn or inhibited [4]. It appears then that descendants of West African slaves who survived the middle passage could have naturally higher androgenic effects in part accounting for the raw athletic talent and high prostate cancer rates seen in African-Americans and Afro-Caribbean peoples. The hypothesis offered seeks to explain how this may have arisen.

Section snippets

Background

This hypothesis emerged from an exploration of the possible interplay between historical events and biological mechanisms resulting in the similarity in the disproportionate racial and geographic distributions in seemingly unrelated phenomena such as sprinting ability and prostate cancer. The hypothesis is equally a synthesis of the interpretations of observations of a disparate nature such as the high incidence and mortality rates of prostate cancer amongst men of African descent in the

Conclusion

I submit that a population shift resulting in increased responsiveness of the androgen receptor in descendants of West-African slaves who survived the middle passage has occurred and is interacting with local environmental and sociocultural factors in the Caribbean and North America to produce the high prostate cancer incidence and mortality as well as the outstanding athletic sprinting ability witnessed in Afro-Caribbean people and African-Americans. This hypothesis is not only biologically

Conflict of interest statement

There is no conflict of interest.

Grant support

There are no grants supporting this work.

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