I am a genetics beginner:
A little back story: My mother was adopted at birth. She found her birth mother and siblings back in the 90s. The birth mother was deceased at the time, and we also discovered that her brothers are ALL her half brothers. My mother was most likely the biproduct of a fling and no one on the bio mother’s side had a clue as to who my mother’s father was, factually speaking, they didn’t even know that my mother existed as the pregnancy was kept a secret from the family apparently. Anyways, I am the son of that adopted woman. Recently a relative that popped up on ancestry.com as a first cousin of mine, not on my fathers side of the house at all or on my mother’s mom’s side.
So here is where the confusion lies...I’m only 37, the relative is 63. My mother is also 63. They both know who their mothers are. They were born a month apart and geographically within 5 miles of one another (father was not named on birth certificate). I have managed to get all three of us into GEDmatch and the numbers in the relationships are as follows:
The genetic relationship by the numbers, according to GEDmatch.com:
My mother to me:
1.0 generational gap
Autosomal DNA: total cM - 3587.1 cM, largest 285.1
XDNA: 196.1 cM, largest 196.1 cM
Relative in question, to me:
1.9 generational gap
Autosomal DNA: total cM - 976.9 cM, largest - 99.1 cM
XDNA: 129.2 cM, largest 129.2 cM
My mother’s relationship to relative in question:
1.5 generational gap
Autosomal DNA: total cM - 1822.5 cM, largest - 129.8
XDNA: 195.3 cM, largest 195.3 cM
What I am seeking is a deeper understanding of what these numbers are saying. My conclusion so far is that the relative in question is either a a half-sister to my mother or her aunt/niece (paternally).
Which is it or is there not enough information?