Accerated Human Brain Development: Cell, Vol 119, 1027-1040, 29
December 2004
Accelerated Human Brain Development May be Due to Increased
Testosterone
It is my hypothesis that human evolution is driven by testosterone
(Androgens in Human Evolution, Rivista di Biologia / Biology Forum
2001; 94: 345-362). I suggest increases in testosterone formed
primates out of mammals (Mitochondrial Eve, Y Chromosome Adam,
Testosterone, and Human Evolution, Rivista di Biologia / Biology Forum
2002; 94: 319-326). That is, increases in testosterone produced
primates and Homo sapiens from primates as testosterone increased.
I suggest the findings of Dorus, et al., may represent the effects of
this increasing testosterone. There is a strong "male-driven" effect
on gene mutation in humans and apes (Kateryna, et al., Nature 2002;
416: 624 and Ebersberger, et al., American Journal of Human Genetics
2002; 70: 1490). This effect is greater in primates than rodents
(Huang, et al., Journal of Molecular Evolution 1997; 44: 463) and is
"particularly pronounced in the human brain," (Enard, et al., Comment
in Science 2002; 296: 233).
The effect may be driven by an increase in percentage of females of
higher testosterone within populations. This would increase exposure
of the fetal brain to increased testosterone which could accelerate
brain development as well as favorable mutations.
James Michael Howard
