It is not possible to use the X chromosome to trace ancestry in any
meaningful way since you cannot identify more than a generation or two back,
who supplied the X. If you test a woman you cannot say which of her two X
chromosomes came from which parent since they both donated one. If you test
a man you know the X came from his mother but you are then again stuck.
In the case of the Y chromosome, it always come from the father which is why
it is use to tracked the paternal line as is done in DNA surname studies.
mtDNA refers to mitochondrial DNA. In most cells in the body there are two
locations where DNA can be found; the cell's nucleus, which in humans
contain the 46 pair of chromosomes including the XX (female) or XY (male)
and in the mitochondria. Mitochondria are distinct organelles in the cell
body that may be thought of as the cell's power source because they make
most of the cell's supply of adenosine triphosphate (ATP), which supplies
the chemical energy for cellular function.
Mitochondria are unique in that they have their own DNA separate from the
cell's nucleus and that the mitochondrial DNA only comes from the mother.
Mitochondria are present in the egg but the male's sperm makes no
contribution to the mitochondrial DNA of their offspring.
Since mitochondrial DNA always come from the mother it is possible to some
extent to use it to track the maternal line. However mtDNA mutates very
slowly and at best tracks changes on the order of thousands of years and
thus has limited usefulness in identifying ancestors within historic times
for family genealogy. It could be used to disprove kinship for example if
your mtDNA failed to match your mother's you cannot be related but it could
not establish a stranger as recent kin since your most recent common
ancestor may have lived 10,00 or even 50,000 years ago.
It is more often used for tracking human migration across the Earth. It can
be somewhat interesting for exposing the distant geographic origins of your
maternal lineage.
The other big problem is that female surnames are generally not preserved.
With mtDNA you are looking at you mother's, mother's, mother's, mother's
and
so on and at some point the surname trail goes cold. With no linkage to a
surname and very low time resolution (compared with Y-DNA) there is just not
much a genealogist can do with the information.
On the other hand if you are curious where in the human diasporas from
Africa your maternal line fits, mtDNA can offer some insight. But of course
it is only your mother's direct maternal line that is preserved so it is
hardly representative of your total ancestry.
Hope this is what you were seeking and good luck!
Dave
-----Original Message-----
From: chapman-bounces(a)rootsweb.com [mailto:chapman-bounces@rootsweb.com] On
Behalf Of Art Pattison
Sent: Monday, September 01, 2008 8:00 PM
To: chapman(a)rootsweb.com
Subject: Re: [CHAPMAN] CHAPMAN Digest, Vol 3, Issue 37
For certain, all femailes have an XX sex chromosome constitution, and males
have and an X and a Y chromosome (the X chromosome being distinctly longer
that an X Chromosome). (Thus it is the sperm that determines the sex of the
offspring, since ova only have a single Y chromosome and sperm cells only
have only an X or a Y chromosome).
What I would like to know is whether one gets a better (more accurate) test
results from a male candidate (ie Chapman descendant) or a female candidate
(eg. Chapman descentant), or maybe it makes no difference at all?
art (the wannabe Chapman)
***************> Date: Mon, 1 Sep 2008 17:26:10 -0500> From:
brycej(a)truman.edu> To: chapman(a)rootsweb.com> Subject: Re: [CHAPMAN] CHAPMAN
Digest, Vol 3, Issue 37> > Could someone explain the maternal dna testing. I
think I understand the paternal side.> The maternal side looks at the
mitochondrial dna on the X. But each female has two X's--one from mom and
one from the dad.> > Can you take this test of both men and women? If you
took it on a male, he would have one X.> > > >
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To unsubscribe from the list, please send an email to
CHAPMAN-request(a)rootsweb.com with the word 'unsubscribe' without the quotes
in the subject and the body of the message
For certain, all femailes have an XX sex chromosome constitution, and males have and an X
and a Y chromosome (the X chromosome being distinctly longer that an X Chromosome). (Thus
it is the sperm that determines the sex of the offspring, since ova only have a single Y
chromosome and sperm cells only have only an X or a Y chromosome).
What I would like to know is whether one gets a better (more accurate) test results from a
male candidate (ie Chapman descendant) or a female candidate (eg. Chapman descentant), or
maybe it makes no difference at all?
art (the wannabe Chapman)
***************> Date: Mon, 1 Sep 2008 17:26:10 -0500> From: brycej(a)truman.edu>
To: chapman(a)rootsweb.com> Subject: Re: [CHAPMAN] CHAPMAN Digest, Vol 3, Issue 37>
> Could someone explain the maternal dna testing. I think I understand the paternal
side.> The maternal side looks at the mitochondrial dna on the X. But each female has
two X's--one from mom and one from the dad.> > Can you take this test of both
men and women? If you took it on a male, he would have one X.> > > >
-------------------------------> To unsubscribe from the list, please send an email to
CHAPMAN-request(a)rootsweb.com with the word 'unsubscribe' without the quotes in the
subject and the body of the message
_________________________________________________________________