Time | A longstanding orthodoxy among social scientists holds that human races
are a social construct and have no biological basis. A related
assumption is that human evolution halted in the distant past, so long
ago that evolutionary explanations need never be considered by
historians or economists.
In the decade since the decoding of the human genome, a growing
wealth of data has made clear that these two positions, never at all
likely to begin with, are simply incorrect. There is indeed a biological
basis for race. And it is now beyond doubt that human evolution is a
continuous process that has proceeded vigorously within the last 30,000
years and almost certainly — though very recent evolution is hard to
measure — throughout the historical period and up until the present day.
New
analyses of the human genome have established that human evolution has
been recent, copious, and regional. Biologists scanning the genome for
evidence of natural selection have detected signals of many genes that
have been favored by natural selection in the recent evolutionary past.
No less than 14% of the human genome, according to one estimate, has
changed under this recent evolutionary pressure.
Analysis of genomes from around the world establishes that there is a
biological basis for race, despite the official statements to the
contrary of leading social science organizations. An illustration of the
point is the fact that with mixed race populations, such as African
Americans, geneticists can now track along an individual’s genome, and
assign each segment to an African or European ancestor, an exercise that
would be impossible if race did not have some basis in biological
reality.
Racism and discrimination are wrong as a matter of principle, not of
science. That said, it is hard to see anything in the new understanding
of race that gives ammunition to racists. The reverse is the case.
Exploration of the genome has shown that all humans, whatever their
race, share the same set of genes. Each gene exists in a variety of
alternative forms known as alleles, so one might suppose that races have
distinguishing alleles, but even this is not the case. A few alleles
have highly skewed distributions but these do not suffice to explain the
difference between races. The difference between races seems to rest on
the subtle matter of relative allele frequencies. The overwhelming
verdict of the genome is to declare the basic unity of humankind.
