[Ger-Poland-Volhynia] 23andMe DNA testing

[Vince Tilroe]

Hi Gail,

You can find me as "zurgleblatz" at 23andMe.

mt-DNA is passed down from mother to child, but only females transmit it to
their offspring.

Y-DNA is only passed from father to son.

The other 22 pairs of chomosomes are called "autosomes", which are
transmitted to both females and males, but each pair of chromosomes
undergoes recombination during each meiosis (occurring in the production of
egg and sperm cells).  The X-chromosome is a bit different in that females
inherit one from each parent (and will recombine when they produce their
own egg cells), but males receive their single copy from their mother.

23andMe's Relative Finder tool uses all 22 pairs of autosomes and the
X-chromosome(s).  There is a bit of a caveat, in that the process of
recombination diminishes the percentage of autosomal DNA inherited from an
ancestor, i.e. on average, 50% comes from each parent, 25% from each
grandparent, 12.5% from each great-grandparent, 6.25% from each 2nd
great-grandparent, and so on.  Thus two siblings will share 50% on average,
a nephew/niece and aunt/uncle will share about 25%, first cousins will
share about 12.5%, and so on.  Thus where more than 10 generations (meiotic
events) exist between any two people (i.e. their shared DNA is a miniscule
fraction of a percent), the certainty of the degree of a possible genetic
relationship can get fairly dodgy and circumstantial.

Please see http://www.isogg.org/wiki/Relative_Finder for more information.

Hope this helps,

Vince Tilroe


Hi,
>
> There was a discussion a few weeks back about 23andMe having a special.
>  Several people said they had their DNA testing done through them and had
> the results on the website.  I have my results back and would like to see
> if I could compare with any others on the group.  I am female and I guess
> we can only compare the MtDNA?   Not sure how all this works.
>
> Gail