Catherine Good Lynch, pictured above, is a potential X DNA donor of mine. In fact, thanks to AncestryDNA, Gedmatch.com, and the testing of another individual at 23 and Me, whose raw data like mine and my mother’s was added to Gedmatch, I know that my mother inherited approximately 34 cM of her XDNA from Catherine. (My brother and I inherited a smidge less at 33.9 cM from Catherine through my mom.)
With a half million individuals who have taken the test at
AncestryDNA this could easily have been a win for Ancestry’s DNA program. But alas, it is not. The DNA test could have been taken with
another company (say FamilyTree DNA or 23 and Me), so Ancestry’s part in this
is limited to providing accurate test results, and, after much pressure of the
genetic genealogical community, providing me with the opportunity to download
the raw data from the tests.
Instead, the victory lap belongs to Gedmatch creators John
Olson and Curtis Rogers, the administrator of the matching individual’s test,
and me.
Below is what the match looks like using Gedmatch’s X DNA “One
to One” Comparison Tool.
For those of you a little foggy on how XDNA is inherited, a
little basic science. Women inherit two
segments of XDNA, one segment from their mother and one segment from their father. When they pass the 1/2 of their XDNA onto
their offspring, they pass a recombined version. One child, for example, could get 10% from
the mother’s father and 90% from the mother’s mother, while another child could
get 50% from the mother’s father and 50% from mother’s mother, or any
combination thereof.
Father’s on the other hand, only have one XDNA segment to
give (because instead of two X Chromosomes, they have that pesky Y chromosome.)
When a father’s DNA is passed onto his child, he can give either an X
chromosome OR a Y chromosome. If he
gives the X chromosome, he finds himself the proud parent of a little girl. If,
on the other hand, he gives the Y chromosome, he welcomes a bouncing baby boy
into the family.
This means two things:
1.
A father
cannot be an X DNA donor to his sons.
2.
The X chromosome that he inherited from his
mother is passed on virtually intact (unless of course there is a mutation of
some sort) to his daughters. For daughters, this means even if they don’t
have access to their father’s DNA, they do have an exact copy of his XDNA, a
copy that hasn’t been recombined.
Below is the path this particular segment took in my branch
of the family.
1.
Catherine Good Lynch would have gotten the segment from one or
both of her parents, Magdalena Click Good and Joseph Good.
 |
| Catherine Good Lynch |
2.
Catherine in turn passed this segment to her
son, John Perry Lynch.
3.
John Perry Lynch passed
the segment on to his daughter, Katheryne, my grandmother.
 |
| John Perry Lynch |
4. Katheryne passed the segment onto my mother.
 |
| My grandmother, Katheryne |
5.
My mother passed almost the entire segment (33.9 of the
34 cM) to at least two of her children, my brother and me.
 |
| Mom |
In my mother’s case, we can document that the segment came from her great grandmother. In the case of mother’s match, the journey was longer. The match received the segment from a sister of Catherine’s, who happened to be the match’s Great great great grandmother.
What is both exciting and frustrating is that this
scientific tidbit has the potential to give proof of the identity of either
Magdalena Click’s mother (purported to be Elizabeth Bauserman) or Joseph Good’s
mother (purported to be Susannah Kaufmann).
I haven’t been able, thus far, to find documentation proving anything
but that researchers have the women’s first names listed correctly. The idea that somewhere within AncestryDNA’s
half a million DNA testers may be the one person whose DNA could corroborate the
identity of either of these women (and potentially their parents!) is so
brightly dazzling that it makes my head spin.
So how about it AncestryDNA. Wanna be my hero? Help me break through those brick walls by
giving me the tools to find my needle in a haystack.
© 30 September 2014, Desktop Genealogist Unplugged, Teresa L. Snyder
