Inconsistent Ancestry Results #dna


David Goldman
 

Greetings, all. Here is something I don't understand. Ancestry shows a young
relative whose great-great grandmother was an elder sister to my
grandfather. She is a "very high match" (49 centimorgans shared across 7 DNA
segments) whereas her own sister shows as an "extremely high match" (72
centimorgans shared across 8 DNA segments). I am stumped why two siblings
would not have the same match numbers. The more I get into this the more
confusing it gets!
David Goldman
NYC


Dorann Cafaro
 

Not so confusing if you stop and think about the fact each of us
inherits some DNA >from each parent and it is specific to us. So your
sibling would have inherited a different mix of DNA than you - some
from your mother & some >from your father but different >from you. Yes
very similar but different. Than consider that each generation back
that mix would have been different again thus one distant mix might be
closer to your mix and one mix closer to some other relative.

The good news is they inherited some on many of the same segments thus
a strong match.

Dorann Cafaro

From: "David Goldman" <lugman@verizon.net>
Date: Sat, 29 Sep 2018 20:49:47 -0400

Greetings, all. Here is something I don't understand. Ancestry shows a young
relative whose great-great grandmother was an elder sister to my
grandfather. She is a "very high match" (49 centimorgans shared across 7 DNA
segments) whereas her own sister shows as an "extremely high match" (72
centimorgans shared across 8 DNA segments). I am stumped why two siblings
would not have the same match numbers. The more I get into this the more
confusing it gets!


David Ellis
 

This is a perfect example of recombination affecting the DNA matches between
him and his second cousins twice removed. He is related to one of their two
parents (say, for the sake of argument, their mother). Each of the two
sisters inherited randomly chosen segments amounting to half of their
mother's DNA, but they inherited different amounts of the segments of her
DNA that matched him.

---
David J Ellis
Natick, MA 01760
djemkitso@verizon.net


Adam Cherson
 

Dear Mr. Goldman,

Please have a look at this article which should help:

https://isogg.org/wiki/Autosomal_DNA_statistics

Good Luck,
Adam Cherson