hair color

Is there much variation in hair color outside of caucasian blood lines? I’d assume no, but a friend mentioned a group of Africans, besides that caused by malnutrition, do have red hair. In anycase, what would “cause” the variation in hair in Euro-cavemen?

Australian aboriginals have varying degrees of reddish and blondish hair in some populations. Keep in mind that most “caucasians” also have dark hair, just like most “caucasians” have brown eyes (since that term encompasses large parts of the M.E., and southern Asia as well as Europe). I don’t think the genetics is fully understood, but it makes sense that the genes which control skin color are also involved in controlling hair color to some degree.

The first humans would likely have started with basic primate coloring, brownish. The Euro-caveman may have resembled them, or may have started to vary.

Besides any environmental selection for coloring, many human groups very probably have selected among themselves for characteristics of ‘beauty’ or ‘impressiveness’. Some may have focused narrowly on a characteristic such as strong resemblance to the existing group, or more pure or intense versions of the existing color (ie blacker, then a glossier black), and others may have selected for ‘exotic’ variations of color.

In my university Physical Anthropology class, and in the (Genetics and Man?) book by Dobzhansky, the point was made that hair characteristics appearing in domesticated animals*, but rarely in wild ones included:
Melanism (fully black): examples among dogs, cats, horses, chickens, cattle, and humans
White (albino and other white): same examples groups as first
Multiple colors within one species or race (ie, palomino, bay, brown, roans, black, white, and so forth in horses): same as first**
Spotting: same as first, except for humans

Besides coloring, other characteristics in domesticated but not wild species:
Curliness: poodles, chickens, sheep and humans
Hairlessness: dogs, cats, and humans (if local hairless areas are allowed, such as most of the body)
Long hair (as opposed to growing to a defined length): poodles, sheep, and humans

You do see one or another of these characteristics in certain wild species, ie black panthers, white polar bears, but the picture isn’t the same as observed in domestics.

The proposed mechanism for this would be selection for appearance’s sake. A farmer with a horse or hen “sport” might often deliberately propagate it. And a human group might see blonde hair or ravens-wing black hair as beautiful and desirable. Some groups might see variations from the norm as undesirable. Which groups went for variety and which went for uniformity would influence the reproductive success of different colors in different groups of humans.

*The intent here is not to describe humans as ‘domesticated’, that would require an IMHO or a GD thread.

**Per some movie, Eskimos referred to Europeans as Dog People, because their hair colors varied as dog colors do.