For example, there are alive today only
about 640
Samaritans, good, bad, and indifferent. Because
their community has been mostly in-marrying for over
100 generations, they form a reasonably distinct
little racial group, with some
unusual genetic patterns.
On the other hand, it can sometimes be
perfectly reasonable to lump the Samaritans in with
their neighbors and more distant relatives in larger and
larger racial groups all the way up to the entire human
race. Just as you belong to various extended families,
each individual belongs to various racial groups.
Whether it's more useful to combine or divide depends
simply on the particular question you are trying to
answer.
A common argument of the
Race Does Not Exist crowd that Leroi didn't deal
with is that, yeah, sure, people differ, but the
variations change evenly across the face of the earth,
so you can never define the boundaries of separate
racial groups.
For example, Science Daily
reports on a
new population genetics study that says:
"… geographic
distance from East Africa along ancient colonization
routes is an excellent predictor for the genetic
diversity of present human populations, with those
farther from Ethiopia being characterized by lower
genetic variability."
The Science Daily article ends with the
Race-Does-Not-Exist-Pledge that is seemingly
obligatory for geneticists who study race (and who don't
want their funding cut off by the
enforcers of political correctness):
"The loss of
genetic diversity along colonization routes is smooth,
with no obvious genetic discontinuity, thus suggesting
that humans cannot be accurately classified in discrete
ethnic groups or races on a genetic basis."
Two fallacies are readily apparent in this statement. First, the whole
argument is a little silly. You could walk from, say,
Calais on the English Channel to Pusan in
South Korea without dying of thirst. At either end
of your vast journey, however, the people look quite
different. In between you might run into, say,
Boris Yeltsin, a blond man with features slightly
reminiscent of East Asia, and other people of varying
degrees of European and East Asian admixture. But, in
the big picture, so what?
Frenchmen and
Koreans are still different and nobody would mistake
one for the other.
Second, the geneticists' statement applies only "along
colonization routes," and most possible directions
were not major colonization routes. If you walk in the
majority of directions, you will eventually fall into
the ocean and drown. This reinforces the "obvious
genetic discontinuity" that we see with our lying
eyes.
For example, one ancient path out of Africa probably crossed the narrow
mouth of the Red Sea from Northeastern Africa to Yemen
on the Arabian Peninsula, and people have been going
back and forth between those edges of Africa and Asia
ever since. That's why some Ethiopians, such as the late
emperor
Haile Selassie, look quite Arabic, and some Arabs,
such as the Saudi ambassador
Prince Bandar, look quite African.
In contrast, up through
1492, there was a relatively massive genetic
discontinuity between West Africa and South America,
which are only 1,600 miles apart at their closest
points. Why? Because the out-of-Africa colonization
routes went the other way around the world. The Atlantic
Ocean got in the way of walking directly from Africa to
South America.
With water covering 7/10ths of the earth's surface, the out-of-Africa
dispersal pathways were, in reality, few and far
between.
Even on dry land, there are vast regions where paths were few and
arduous. For instance, between the
peoples of West Africa and of the
Maghreb (Northwest Africa) there was only a small
amount of mating until historic times, because the
Sahara got in the way. If you tried to walk from Senegal
to the Pillars of Hercules, you would likely die of
thirst. The eastern end of the Sahara, though, is more
porous because of the Nile and some wetter highlands.
Likewise, the Himalayas form a sharp border even today between
Caucasians and East Asians.
The Science Daily reported finding that further-traveled groups
have less genetic diversity supports the
Out-of-Africa theory of the origins of modern
humans. The farther a racial group lives today along the
ancient paths from the exit points in northeast Africa,
the fewer different ancestors they had and the more
recent those different ancestors were. And thus, the
less genetic diversity their modern-day descendents
possess.
For example, only a few prehistoric humans made it all the way to the
bottom of South America, so today's Patagonian Indians
are typically descended from fewer different individuals
than, say, Middle Easterners, who live at the crossroads
of the world.
Please note that this study applies mostly to "neutral
genes," not to genes that necessarily do anything.
The common claim that Africans are the most genetically
diverse people is true only of junk genes. Africans are
not necessarily more physically or behaviorally diverse
than other races, as
facile pundits like
Malcolm Gladwell assume.
I'll try to be methodical about this question of
topographical barriers. Let's split the world up into
seven effective continents: Sub-Saharan Africa, West
Asia, Europe, East Asia, Australia, North America, and
South America. (Other breakdowns are possible; but the
results will all be about the same.)
Here is a table showing seven major continents and my guess as to how
easy the potential direct colonization routes between
each of them were during early human prehistory: A "2"
means easy, "1" means difficult but used, and 0 means
there was virtually no direct contact between the two
continents before historic times. As you can see, it's a
sparse grid