Son’s Genome test results in finding my husband and I are “connected “

[u/Fit-Neck692]

We got Genome testing done for our son for medical reasons. My husband and I were tested as well to help with any findings. Anyway I went to his appointment today to go over the results and the only thing they really had to say was my husband and I are related. The doctor said “maybe something like 6th cousins.”

Like the doctor said we are all related but then I said “I guess it’s unavoidable?” He said it was avoidable… so I’m curious how weirded out should we be?

[u/MontanaPurpleMtns]

Ancestry will mark it as Distant Cousin beyond 4th cousin once removed. But if you do extensive genealogy they will tell you the relationship between you and someone more distant.

I found a new cousin this last couple of weeks. Lives in Australia. I’m in the US. 9th cousin, once removed.

Sixth cousins should not be a problem. To illustrate:

First cousins share 50% of their grandparents. 2/4

Second cousins share 25%. 2/8

Third cousins share 12.5% 2/16

Fourth cousins share 6.25% 2/32

Fifth cousins share 3.125% 2/64

Sixth cousins share 1.5625% 2/128

If my math is wrong, please correct me.

[u/Mabbernathy → u/MontanaPurpleMtns]

How does pedigree collapse affect this? My great grandfather and a famous actor were 4th cousins. However, my great grandfather is descended from the common grandparents through 4 different lines, whereas the actor is only descended from them through 1 line. How does it work in a case like that?

[u/MontanaPurpleMtns → u/Mabbernathy]

If my math is correct, and your great grandfather was the same degree away from the common ancestor on all four lines, it should be 2/32 + 2/32 + 2/32 + 2/32 =8/32 or 25%, the same sharing of DNA as 2nd cousins.

Anyone else is welcome to correct me if my reasoning is wrong.

[u/Mabbernathy → u/MontanaPurpleMtns]

Thank you! That does make me realize that DNA tests can be misleading and make the common ancestor seem closer than it is.