Why do GEDMatch #'s not show relationship to my #?

+2 votes
I have checked the Gedmatch #'s on my family page & it doesn't show we are related? I do not understand why not?
WikiTree profile: John Moore
in Genealogy Help by Florence Moore G2G1 (1.1k points)
retagged by Lynda Crackett

1 Answer

+5 votes
Best answer
John is too far back.

The autosomal DNA tests can only test 4 to 5 generations back with any accuracy. This is determined by the amount of shared DNA getting halved in each generation as you go back.

Your parents are halved, your grandparents have one quarter, your great grandparents have one eighth, your great great grandparents have one sixteenth - and that is 4 generations (not counting yourself) right there.

So the autosomal tests can only test DNA accurately between 100 and 150 years ago - assuming 25 years per generation.

John was born and died in the 1700s. Which is definitely too far back!!

Edited to add - If Moore is your married name then you can never be related to John Moore. Your husband is related to him. However the DNA connection still wont show up - for the exact same reason I gave above.

PS thanks for the best answer.

The email says Sheppard-2686 - so thank you PIP Sheppard.
by Robynne Lozier G2G6 Pilot (930k points)
edited by Robynne Lozier
Wikitree does set a strict cut off on how far back it shows the DNA trail. It would however, be possible to have inherited a significantly large segment of DNA from an ancestor beyond that cut off to be showing matches on your test site or on gedmatch with other descendants. The probablility is low, but it does not impact on the accuracy of the test. I have triangulated matches which go back to the 1700s. Also, having the married name Moore certainly does not preclude having a DNA trail to an ancestor of the name Moore.

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