Confusing Ancestry Results

[pollycat76]

My son M matches his father's brother D with 789 Cms. Ancestry say on M's results that D is 1st-2nd Cousin. D's results show my son M as nephew. I see from DNA Painter that 789Cms is more likely to be half uncle ! M's other known cousins have 770 and 892 Cms matches respectively. Other than the obvious, is there an explanation for this "Uncle's" result ?

[IgorStrav]

Whilst I can't answer your specific example, I do know that the shared DNA varies very extensively between 'equal' relatives.

My 2nd cousin once removed (who I know, and is documented, we are related via my great aunt), shares 17cM DNA with me.  DNA painter has that relationship as a 1% likelihood.

It's previously been suggested here that there must have been an NPA for that amount of DNA share

However, knowing the circumstances/background of my great grandmother, (wife of Metropolitan policeman, close family, 12 children, when would she have had the time???) I'm more inclined to believe it's an outlier.

[Gadget]

M's other known cousins have 770 and 892 Cms matches respectively

Is this is with M or D ?

Assuming that it is with M, are you able to find how many cMs they share with D. Also, have you checked through the shared matches that M has with D.


Gadget

[pollycat76]

I should have said the cousins were on M's maternal side just to show those are in the "normal" cousin's range. I have checked M's shared matches with D and there are some 2nd to 3rd Cousins with Cms between 102 and 232 and the ones I have been able to trace back on the family tree are on D's maternal side.

[Gadget]

I see. Are there any links to Ds paternal side?