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From: doug@hpcilzb.HP.COM (Doug Hendricks)
Newsgroups: sci.bio
Subject: Genetic Mosaic Humans
Message-ID: <2630003@hpcilzb.HP.COM>
Date: 4 Dec 89 18:17:12 GMT
Organization: HP Design Tech Center - Santa Clara, CA
Lines: 33

Hello, I'm new to this net.group, but I have a heard something very strange
and want a reference to any relevant articles.

In the San Jose Mercury News (Dec. 3 Morning, 1989), on page 1P is an article
by Charles A. Gardner, who "is conducting his doctoral research on the genetic
control of brain development at the University of Michigan Medical School
Department of Anatomy and Cell Biology." In this article, he states:


"If a fertilized mouse egg from two white-furred parents goes through 4 cell
divisions, the embryo will have reached the 16-cell stage. If this embryo is
then brought together with a 16 -cell embryo from two black-furred parents,
a ball of 32 cells is formed. This ball of cells will go on make a single
individual with mixed black and white fur: one mouse with four parents..."
...
"A similar event sometimes occurs naturally in humans when two sibling embryos
combine into one. The resultant person may be completely normal."

Mr. Gardner implies that such humans are known and identified. It is true?
Do we have people walking around with two different genetic sets?
Is there documentation? Mr. Gardner doesn't list any sources. His article
was on another topic and he mentioned these genetic mosaic humans only to
make a point.

Actually, this idea is not entirely new to me. There is a form of Down's
Syndrome called Mosaicism, where some portions of the person's body carry
the normal 46 chromosomes and the rest of the person's body carries the
47 chromosomes of the common form of Down's Syndrome called Trisomy 21.
Mosaicism (possibly misspelled), after "mosaic", is very rare, but
documented. Sorry, I don't have references, my wife used to be a speech
therapist who worked with people with Down's, and I just remember reading 
a pamphlet on the varieties of Down's Syndrome (Trisomy 21, 98% of cases;
Translocation 15-21, most of rest; Mosaicism, very few).