RE: Recommended PBS TV Program

The PBS channel (Detroit) that we can get here did not list the program, so
I didn't get a chance to see it. Not being a biologist or anthropologist, I
have a question. A ~60 000 year time span is apparently sufficient to
generate the differences we see in the various races. How long (how many
generations) does it take for racial traits to develop? I realize this is a
vague question because "racial traits" is not a well-defined term. But you
know what I mean. I realize that differentiation requires isolation and
that, as the program apparently pointed out, increased migration is likely
to soften or remove these differences.

Chuck Vandergraaf

  _____

From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of Randy Isaac
Sent: Saturday, January 07, 2006 5:42 PM
To: asa@calvin.edu
Subject: Re: Recommended PBS TV Program

I just finished watching the show and enjoyed it very much, though at spots
it was sensationalized a bit. If I got the story right, this man was the
one, out of several hundred in central Asia whose blood was tested, that had
the clearest evidence of the Y-chromosome marker indicating the connection
with the group migrating out of Africa and also found throughout Europe and
Asia and the Americas.

Wells focuses on Y chromosome mutations. If there were no mutations, all Y
chromosomes would essentially be the same, passed down from male to male.
Clearly defined mutations can be markers for tracking ancestry. But the
markers can be lost over time if they get commingled with other mutations.
Using this technique, he claims to have traced the migration of humans out
of Africa. The first group went to Australia through the coastal path
through India. The second group went to central Asia, where he found this
gentleman, and from there humans went in several directions, including
Europe and over the Bering Strait to the Americas.

I was intrigued by his comment on timing. Until the last ten years, the
technology and insight didn't exist to be able to detect and trace these
mutations. But he claimed in a few more generations these markers would be
too diffuse to trace. The timing is just right to make the discovery now.
Sounds close to the anthropic argument to me.

Randy

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Received on Sun Jan 8 21:51:17 2006