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Climate May Affect the Testosterone to DHEA Ratio of Human Evolution

Posted by jamesmhoward on 17 Mar 2017 at 10:04 GMT

It is my hypothesis that human evolution is driven by increases in female testosterone resulting in changes in the testosterone to dehydroepiandrosterone (DHEA) ratio. ("Androgens in Human Evolution," Rivista di Biologia / Biology Forum 2001; 94: 345-362. If your library does not subscribe to "Rivista ... ," you may find this at: http://anthropogeny.com/A... ) The first evidence of this may be the increased size of females, not a decrease in males, that reduced sexual dimorphism in Homo erectus.

Differences in testosterone and DHEA ratios occurred because of separations and concentrations within populations caused by geographic and climatic changes and dominance hierarchy. If significant, subsequent alterations of these ratios did not occur, the effects of these ratios may remain relatively stable. The effects of the ratio of these two androgens affect gene expressions which, I suggest, have been interpreted as different species and races.

So, I agree with Zaidi, et al., that "some aspects of nose shape may indeed have been driven by local adaptation to climate."

No competing interests declared.
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