flow of the nile wrote:
Have you ever seen two short Asian people produce a child that looks like Manute Bol just by putting the baby food on a higher shelf in strong sunlight?
The genes of Kenyans have already been selected for and triggered by heredity and all those other factors.
It doesn't happen just because you want it to.
No, but I have seen two parents of slightly above - average height (dad 6' 0", mom 5'7") give birth to a son that's 6'5" and weighed 245lbs when he graduated college. Bol's parents were 6'10" and 6'8" and he was 7'7" which is close to a foot taller than is father, and 9 inches taller than his mother. There are cases of "breeding" for height/build/etc., but these changes occur over many generations in relatively small populations. (think family or small village sized populations) The genetic makeup of East Africa, or Kenya, or even the Kalenjin is much too diverse to produce the kind of genetic outliers on a population-level basis that would lead to a single country or region dominating the modern marathon. A family of great distance runners, or a village of (relatively) closely related family members might possess a genetic mutation that gives them superior athletic ability. But Kenyan genetic makeup is no more homologous than that of Britain. There are tall Kenyans, short Kenyans, fat Kenyans (when they're rich enough to be fat), skinny Kenyans, just like there are tall/short/skinny/fat Brits.