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Archiver > GENEALOGY-DNA > 2005-05 > 1116606571


From: "Andrew and Inge" <>
Subject: RE: William the Conqueror
Date: Fri, 20 May 2005 18:29:31 +0200
In-Reply-To: <6.2.1.2.2.20050520021657.027de008@pop-server>


I am not sure this can be taken as an axiom. It is true that everyone with
European MIGHT have a common ancestor that recently, but it is not sure. You
can't take the maths too simply. Just to mention the most obvious problem...

I presume that the number you compute assumes that the number of places on a
family tree for a particular generation EQUALS the number of ancestors a
person has in that generation? In fact when you go back a lot of generations
in a particular geograpical area where most people have children with other
people from the same area, you can expect to descend many times from the
same smaller number of people, thus reducing the number you say you can
compute a lot. (On the other hand, this would be less true for the
nobility.)

You might be interested to know that there was an article in Nature about
this type of question last year. Should be reasonably easy to find.

For me the article introduced a new concept: in addition to the most recent
common ancestor so often referred to by genealogists using DNA, there is a
time before the MRCA (the most recent person from whom we all descend, in
this case not only along paternal lines) of a population when everyone who
was alive and who has descendents still alive now, will ALL be ancestors of
EVERYONE alive now.

So before the MRCA of all people there was the most recent common paternal
ancestor. And before this Adam there was "mitochondrial Eve" and before her
there was a time when everyone who still has descendents is an ancestor of
all of us. Thinking about this type of thing is very helpful in
understanding how genetic diversity, and the number of surnames, can
decrease (thus making it difficult, by the way, to calculate when Y-Adam and
mt-Eve were).

Andrew



-----Original Message-----
From: Cole [mailto:]
Sent: Friday, 20 May 2005 8:45 AM
To:
Subject: William the Conqueror


"We are all related to Charlemagne"

As I understand it this is an axiom. If you compute the number of ancestors
of yourself back to William's time you will have a number larger than the
world population at that time. You then are related to everyone alive 1000
years ago and are also related to
Charlemagne. I would think this would still hold for his grandson William
although our relation to him is 1/4 that of Charlemagne's.

Cole

>Of course William has vast numbers of non-all-male descendants,
>probably more than 100 million. I am one with a huge number of lines
>to him.
>
>Doug McDonald
>


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