On Mar 26, 8:00 am, zinnic gate.net> wrote:

...the features that we depend on to identify whether a person is
caucasoid, negroid, or mongoloid, etc., are the superficial soft parts
of the body. Lips, noses, hair, eyes, and skin do not fossil- ize. At
the same time, the hard parts that do get preserved are not reliable
as racial markers because almost all of the skeletal dimensions of all
the races overlap. But there is a more profound problem with trying to
say how long the contemporary races have been in existence. Genes that
determine features used for denning contemporary races need not form
permanently associated hereditary bundles of traits. Variants of skin
color, hair form, lip size, nose width, eye folds, and so on can be
assorted and inherited independently of each other. This means that
the traits that go together today did not necessarily go together in
the past, or indeed even existed in the past, among the populations
that were ancestral to today's racial groupings.

Even today, there are so many different combinations of racial traits
around the world that no simple scheme of four or five major racial
types can do justice to them. Millions of people with thin lips, thin
noses, and wavy hair, but dark brown to black skin, live in North
Africa. Native inhabitants of southern Africa, such as the San, have
epicanthic eye folds (like most Asians), light brown to dark brown
skin, and tightly spiraled hair. India has people with straight or
wavy hair, dark brown to black skin, and thin lips and thin noses. On
the steppes of central Asia, epicanthic eye folds combine with wavy
hair, light eyes, considerable body and facial hair, and pale skins.
Indonesians have a high frequency of epicanthic eye folds, light to
dark brown skin, wavy hair, thick noses, and thick lips. Inhabitants
of the islands of Oceania present combinations of brown to black skin,
with contrastive forms and quantities of hair and facial features. An
interesting bundle of traits occurs among the Ainu of northern Japan,
who have light skin and thick browridges, and are the hairiest people
in the world. In Australia, pale to dark brown skin color and wavy
blond to brown hair are common.

Ignorance or denial of the separability of traits used for racial
identity can lead people to create strange biological categories. The
distinction between blacks and whites in the United States, for
example, ignores the obvious fact that individual blacks can have
eyes, nose, hair, and lips that are indistinguishable from these
features among whites. The reverse is also true of whites, among whom
some individuals look more negroid than some blacks. These anomalies
occur because Americans do not mean by race what people actually look
like as determined by their genes but by how their parents were
classified. According to this conception of race, if one parent is
"black" and the other is "white," their child is "black," despite the
fact that by the laws of genetics, half of a child's genes are from
the black parent and half from the white. The practice of cramming
people into these racial pigeonholes becomes absurd when black
ancestry consists of only a single grandparent or great-grand-parent.
This produces the phenomenon of the white who is socially classified
as "black." Most American blacks have received a significant portion
of their genes from recent European ancestors. When samples of
American blacks are studied, the assumption that they genetically
represent Africans is incorrect. Perhaps we would do well to emulate
the Brazilians, who identify racial types not by three or four terms
but by 300 to 400, in proper deference to the fact that people whose
parents and grandparents were a mixture of Europeans, Africans, and
American Indians cannot be said to be either Europeans, Africans, or
American Indians.

Traits that we can see don't stick together with those we can't. Take
the ABO blood groups. Between 70 percent and 80 percent of light-
skinned Scots, black-skinned central Africans, and brown-skinned
Aborigines of Australia all have type 0. If we could see type 0 blood
groups the way we see skin color, would we put the Scots and the
Africans in the same race? Type A is equally unmindful of skin-deep
distinctions. Africans, East Indians, and Chinese all have 10 percent
to 20 percent frequencies of type A. Should we put them all in the
same race?

Another example of an invisible trait that blithely ignores
conventional racial boundaries is the ability to taste PTC
(phenylrhiocarbamide). In 1931, a laboratory researcher accidentally
dropped a sample of this substance. Fellow workers complained about
the bitter taste that it produced in their mouths; others said they
tasted nothing. Anthropologists now know that the world is divided
into PTC-tasrers and non-PTC-tasters. In Asia, nontasters range from
15 percent to 40 percent. There are twice as many nontasters in Japan
as in China, and three times as many in Malaysia. Does this mean that
each of these groups belongs to a separate race? If tasters could see
nontasters, would they make fun of them and refuse to let them into
their neighborhoods or their schools?

New combinations and frequencies of genes have kept the species'
racial types in a state of flux ever since populations of modern
sapiens began to spread throughout Africa and Eurasia. Some of these
changes reflect the workings of chance. During migrations by small
groups into new regions, the settlers by accident may happen to have
had a high frequency for a gene that was rare in their ancestral
population. Thenceforth, the new population had a high frequency of
the variant. Such a scenario could account for the distinctive shovel
shape of the incisors of Asian peoples.

An accelerated flow of genes when migrants encounter genetically
distinct populations is another essentially random process
contributing to the evanescence of racial types. During earlier times,
nothing quite so massive as the blending of races in the United States
and Brazil could have happened, yet some degree of race mixture would
have been unavoidable at the shifting boundaries between genetically
distinct populations in remotest antiquity.

Finally, as is generally true of all biological evolution, a major
cause of the shifting distribution and frequency of genes
conventionally used to identify racial divisions is natural selection.
As populations move into different habitats or as environments change,
selection for reproductive success leads to the appearance of new
bundles of hereditary traits.

Anthropologists have made a number of plausible suggestions relating
racial differences to temperature, humidity, and other climatological
factors. For example, long, narrow noses of Europeans may have been
selected to warm extremely cold, damp air to body temperature before
it reached the lungs. The generally rounded, squat bodies of Eskimo
may also represent adaptation to cold-Bergman's rule again. A tall,
thin body, in contrast, leads to maximum heat loss. And this may
explain the tall, thin bodies of Nilotic Africans, who inhabit regions
of intense arid heat and whose descendants make some of the world's
greatest basketball players.

Ironically, traits whose frequencies are determined by natural
selection are not very good markers for the purpose of reconstructing
the history and antiquity of today's racial divisions. Suppose, for
example, that people with short noses migrate from a tropical to a
cold climate. Within a few-score generations, natural selection will
increase the frequency of long noses'among them. An observer noting
the similarity between them and their long-nosed neighbors might
readily conclude that they were descended from a long-nosed cold-
climate race rather than a short-nosed hot-climate one. So the best
markers of racial ancestry are traits that are accidental or
nonadaptive, like the shovel-shaped incisors I mentioned a moment
ago.

Unfortunately, many of the traits that anthropologists once thought
were the best markers of racial ancestry have turned out to have
adaptive value in certain contexts. Blood groups were a particularly
keen disappointment, for it turns out that the ABO series is linked to
resistance to diseases that may affect reproductive success, such as
smallpox, bubonic plague, and food poisoning by toxic bacteria. So the
explanations for blood-type frequencies probably lie as much in the
history of transient exposures of different populations to different
diseases as in racial ancestry. Even a trait as cryptic and seemingly
useless as the ability to taste PTC may not indicate common descent as
much as similar adaptive responses by ancestrally separate
populations. Chemically, PTC resembles certain substances that have
adverse effects on the functioning of the thyroid gland. A common
consequence of thyroid malfunction is goiter, a crippling, life-
shortening disease. In populations at risk for goiter, the ability to
taste foods containing the PTC-like thyroid-inhibiting substances
would be selected for, rendering the distinction between taster and
nontaster unreliable for reconstructing racial ancestry.

OUR KIND by Marvin Harris 1989
http://www.amazon.com/exec/obidos/tg/detail/-/0060919906/