Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!bryans
From: bryans@ux1.cso.uiuc.edu (Bryan Siegfried)
Newsgroups: sci.bio
Subject: Re: We've got Eve. Now what about Adam?
Message-ID: <1990Dec8.014156.15393@ux1.cso.uiuc.edu>
Date: 8 Dec 90 01:41:56 GMT
References: <15461@cs.utexas.edu> <0bLsVz600Vpb0ftUp_@andrew.cmu.edu> <15566@cs.utexas.edu> <1110@ai.cs.utexas.edu>
Organization: University of Illinois at Urbana
Lines: 32

throop@cs.utexas.edu (David Throop) writes:



>about 200,000 yrs ago, there was one woman who was the matrilineal
>mother of us all.  These studies have used analysis of mitochondrial
>DNA, because it is inherited only matrilineally.  Genetic drift studies
>were used to gauge how far back this "Eve" lived.

...

>  What about finding the same for men?  Isn't the Y chromosome the
>analog of the mitochondrial DNA?  It is passed entirely from the
>father's side.  Isn't the Y chromosome in my cells just a many-time
>copy of my great^N-father's Y chromosome?   
>    Shouldn't genetic drift analysis also be able to gauge how far back
>it was that there lived a man who was the patrilineal father of us all?
>    Or has this already been done?

	The Y chromosome is in the nucleus, and like most eukaryotic
DNA (organelle DNA excepted), many mechanisms are present to protect
the Y chromosome from being changed.  Mitochondria have almost no 
mechanisms to maintain their genetic integrity.  Over 200,000 years,
the mitochondrial DNA will change enough for genetic drift studies to
be done.  However, in 200,000 years (a reasonable estimate for the
Y-chromosome Adam), there would be very little change in the Y chromosome.
With such little change, a similar genetic drift study wouldhave very
little accuracy.

__
Bryan Siegfried							zig@uiuc.edu
			Biology and Economics at UIUC