From: Damien Broderick (thespike@earthlink.net)
Date: Sat Dec 21 2002 - 20:25:16 MST
Avatar Polymorph writes:
> Personally, living in Asia (Australia), I find the phrase Asian
> meaningless. [etc]
Here's a recent review by me from the Weekend Australian newspaper; I trust
I haven't posted this previously, but I'm working on someone else's machine
right now:
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Mapping Human History: Discovering the Past Through our Genes
By Steve Olson
Bloomsbury/Allen&Unwin
Lots of people look and act differently from us. Many of them now live just
down the street. Racism is one of history's dopiest reactions to that fact.
Will today's treasury of genetic discoveries help expunge such
stupidities--or reinforce them? Genes hold intriguing clues to our past.
The stories they tell can be confronting, especially to those who preen
themselves as ethnically spotless and superior.
Bigots and racists lump people into pre-judged groups using some
blindingly apparent and skin-deep discriminator: sex, or age, height,
melanin tone, eye shape, hair type, verbal accent. How on earth did this
get started? We do seem to have a penchant for carving the world into kin
(however loosely defined) versus the rest. Some people we proudly gather
inside the `us' boundary. The others we lock out behind the `them'
boundary. All too often, these groups get confused with `friend' versus
`foe', `sexually unappealing' versus `wickedly attractive', and many other
opposed categories.
Bigotry quickly feels all too natural. Even those who pride ourselves on
being `color-blind' can slip into old habits. White against black is only
the crudest of these arbitrary divisions, apparently sanctioned by common
descent from sacred or secular heroes steeped in some blood-drenched
landscape. Soccer teams make a fetish of it.
Identifying ancestry-based groups of humans as `races', then ranking them,
is not just arbitrary, grounded in ancient wrongs and self-interest, but
systematically misleading. Now we're unpacking the genome, uncovering the
immensely complex endowment of various alleles (that is, the gene variants
underlying physical features--for eye color, say, or blood type).
American science writer Steve Olson tells a very accessible, widely
researched tale of how humanity's genes map out a vast, tangled history of
virtually identical tributaries in the great river flowing out of Africa
100,000 years ago. All the world's human plenty funnels back to one common
maternal ancestor 200,000 years ago, dubbed Mitochondrial Eve, and one
common father 50,000 years later, whose Y genes form the basis of every
male alive. Obviously these are not the Biblical first parents, just those
whose lineage has never once faltered along the road to us. The variant
haplotypes, or slightly different versions of mitochondrial and Y chains,
are a sort of chemical map of the peoples they've passed through.
Obviously we're not identical, so the enterprise has its risks. An expert
in Hawaii, with its remarkably mixed population, warns against using
genetic markers to prove ethnicity: "I don't believe that biology is
destiny. Allowing yourself to be defined personally by whatever your DNA
sequence is, that's insane. But that's exactly what some people are going
to be tempted to do."
But aren't some groups of humans--some `races'--known from IQ tests to be
smarter or dumber than others, even though nobody is allowed to mention
this any more? Olson notes that the claim is fallible. The Buraku of Japan
are "a minority that is severely discriminated against in housing,
education, and employment. Their children typically score 10 to 15 points
below other Japanese children on IQ tests. Yet when the Buraku immigrate to
other countries, the IQ gap between them and other Japanese gradually
vanishes." Conservative black American scholar Dr Thomas Sowell observed
recently that over five times as many black girls as boys score above 140
(highly gifted). Social not inherited factors are at work.
Chinese specialists still favor the idea that different peoples evolved
separately from proto-human stocks spread about the globe. Molecular probes
quash this possibility. Everyone on earth is African, although most of us
have less genetic variability than those like the Bushmen who remained in
the original continent. That's because some gene variants were lost during
the migrations. But one charming discovery cited by Olson is that much of
Southeast Asia was seeded from Australia and New Guinea, 20,000 or more
years after the first ancestors arrived here. Arguably, those boat people
are just coming home.
The heart of Olson's book is the double adventure of mitochondria, ancient
assimilated bacteria handed down the maternal line, and Y-chromosomes,
carrying the male sex genes. Mapping the four-letter sequences of DNA bases
along these tiny genetic chains lets scientists find the places where
mutation added variety to the basic code. Sexual reproduction mixes and
re-sorts our gene variants, and over time new mutations or random changes
enter each lineage. In isolated regions, the variants narrow and persist,
while in the melting pots they spread and multiply. Tracking these markers
lets us estimate how long a particular group has been away from the African
homeland, and more intriguingly which geographical routes its ancestors
took to get where they are today.
Languages, too, mark out groups and peoples, although they change faster
than genes, and can be adopted without marrying into new families. Still,
historically, the two went hand in hand. A celebrated geneticist, Luca
Cavalli-Sforza, has traced genes and tongues alike, mapping a controversial
history of dispersion. His views are becoming accepted as ever more nuanced
genomic studies draw out the ancient blends of migration, marriage (and
rape), spoken and written languages.
The details are dauntingly complex but Olson tells the tale as clearly as
you could hope for, in a story full of startling connections and the
mandatory human interest details of its explorers. In a poetic flourish, he
cites Hermann Hesse's Siddhartha: "Each one was mortal, a passionate,
playful example of all that is transitory... continually had a new face;
only time stood between one face and another." Olson foresees a future in
which panmixia--the blending of all today's peoples--will reverse the
dispersion of our genes. That is surely too tame a prediction. The same
genetic technology that revealed Mitochondrial Eve will allow us to blossom
forth in such a profusion of chosen variety that racism will be laughed to
scorn and then forgotten. The mother of that new epoch might be, perhaps,
Mitochondrial Dawn.
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Damien Broderick
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