Africa is the most genetically diverse continent on Earth—Africans being “more genetically diverse than the inhabitants of the rest of the world combined,” according to one 2009 study—and no single physical characteristic demonstrates this diversity better than height. Africa is home to the tallest ethnic groups on Earth (the Dinka, Tutsi, and Maasai) and the shortest (the Aka, Efé, and Mbuti), and people in the latter category (along with other ethnic groups with a <5′ median height, such as the Batwa people of Central Africa) have historically been classified as pygmies. It’s not a terribly helpful designation, in part because there’s no corresponding widely-used term for unusually tall people, but anthropology has never been an exact science.
Fortunately, genetics is an exact science (well, more or less), and study of gene markers has introduced some badly-needed hard science into the discussion of what the pygmy phenotype is and where it came from. Scientists have recently discovered that it is a recent adaptation that emerged independently in different communities, mediated by different gene markers:
The researchers investigated 16 different genetic locations that were associated with short stature when they looked at individuals who were an admixture of Batwa and Bakiga …However, when they looked at the Baka of West Africa, they did not find the same types of changes in the 16 genetic locations.
“What we think we see is that regions of the genome that are involved in the Batwa’s Pygmy phenotype do not look the same in West Africa,” said Perry. “If the Pygmy phenotype were really old, then we would have expected the locations to be similar.”
The authors argue that the pygmy phenotype could have been a necessary adaptation in rainforest terrain; in a matter of centuries it may prove equally helpful in the industrialized world, where short people tend to live longer than their taller counterparts. But for now, greater height still correlates to power in many communities; it can even be used to delineate an ethnic caste system, and communities associated with the pygmy phenotype are organizing to confront these problems directly.