CARIBBEAN-L Archives

Archiver > CARIBBEAN > 2003-02 > 1045247889


From: "Edward Crawford" <>
Subject: Re: DNA testing
Date: Fri, 14 Feb 2003 18:38:09 -0000
References: <1CDF2224.521BBE75.0B776812@aol.com>


I take your point that there are differences within different societies and
different family structures etc and the meaningless of saying someone is a
percentage of some ethic group. (Ethnicity is as much or more a SOCIAL
construction as a genetic one.) But the Sykes group is interesting, It was
pretty random, half had the same male ancestor and the line is reckoned to
start 700 hundred years ago. Some were middle class of course but not all
clearly, many were ordinary people and still they got that low result. And
there could be another route to get the Sykes name. A Sykes girl who had an
illegitimate child but which was brought up by and named by her parents,
that happened frequently. So if you mean British people in the period
1300-1850 I reckon it is pretty strong evidence.

Edward Crawford
----- Original Message -----
From: <>
To: <>
Sent: Friday, February 14, 2003 3:10 PM
Subject: Re: DNA testing


> You may be right, Edward for many societies, or for some social sets, but
keep in mind these are supposedly general population statistics from many
different places and many different social groups. 10% was the high I recall
in a range that started a lot lower. But even if it's 2%, it doesn't take
many generations for that to introduce serious uncertainty as to where that
Y chromosome came from. This doesn't make a match any less significant
(although there may be complicating factors there too), but it does mean if
you don't find a match, it doesn't necessarily mean your genealogical
ancestor was not a biological descendant of the person in question. The
chain may have been broken at some point. I know I am my father's son
because my mother says so, and I look like him. I can be reasonably sure my
father was my grandfather's son for similar reasons. Farther back than
that, I can't truthfully say that I 'know' much.
> As somebody pointed out, either Y chromosome or mitochondrial DNA testing
gives a very narrow picture of one's ancestors. I read in the paper (NY
Times) the other day that 8% of all men within the borders of the old Mongol
empire have a Y chromosome that comes from the same source and that source
is speculated to be Genghis Khan. (This is not too implausible given that
he supposedly had 20,000 descendants within a century or so of his death
thanks to polygamy). But that doesn't mean everyone in that (huge) area is
8% Genghis Khan; just that 8% of men have that chromosome due to a very
efficient distribution system and energetic distributors. And given the
random shifting of nuclear genes every generation, and the impossibility of
telling where most of them came from (because most of everybody's are so
similar), I question whether it is a meaningful statement to say one is 25%
African (per the BBC website). The only way you could know that for sure is
if you had a grandp!
> arent from Africa. Anyway I wonder exactly what that means.
>


______________________________________________________________
This message has been scanned by the Datanet VirusScreen Service,
powered by BT Ignite and Messagelabs. For more information please
visit http://www.VirusScreen.co.uk.

This thread: