Ancestry DNA matches - can they skip a generation?

[RichardK]

Hello

My wife did an Ancestry DNA test a few months ago. Looking through the people with whom she had DNA matches and looking at their family trees, we found a match with a person X where it was possible to identify common ancestors - some of my wife's 4 x great grandparents on her father's side. However, her father has just done the test, and person X doesn't appear to be listed as a match with him at all. Does this mean that our original identification of the common ancestors was not, in fact, the source of the DNA match and that the DNA match with person X must be on my wife's mother's side? (Even if the documentary evidence suggests they're also related through the identified common ancestors on her father's side.)

Alternatively, is it possible that the DNA link is the common ancestors we've identified and there's something in the way Ancestry compiles its results and matches which might make it recognise the match with X for my wife but not for her father?

Thanks
Richard

[hurworth]

Are you meaning that your wife's father has subsequently tested and doesn't match person X?

[Jan_A]

Also remember that some DNA can "disappear" but that is from further generations out.  Ex: If you have Native American relatives way back.  Say a person was half Indian, they marry: their children will be 1/4 Indian.  When those children have kids, they will be 1/8 and so on... the more generations it goes down - the less percentage there will be, though traits may still be there (hair, skin tint etc).

I am having issues with mine as well (from ancestry DNA). We never knew my father's family, we know my mom's.  We could only do mine and my mom's DNA.  I have 50% G. Britain (people living in England have about 60% normally), 22% W. Europe then 10% Scandinavian.  Now my mom's is 46% Scandinavian, 14% W. Europe and then 13% G.Britain.  So this would mean that my DAD's family is giving me the majority of my G. Britain.    So far I'm tracing his family to Germany and Ireland.  GRANTED a lot of folks back in the day migrated to England THEN after a year or two moved on to the West..but still it makes me go    but makes me dig that much further!

I feel for you!
Jan_A

[RichardK]

Thanks both

Hurworth - yes, that's exactly right. Wife's father has now tested, but he doesn't come up on Ancestry as having a match with person X.

Thanks
Richard.

[hurworth]

Hi Richard,

If this match was via your father-in-law then he would be a match as well, and usually a better one.

My understanding is that Ancestry doesn't have a chromosome browser or tell you much about how A matches B or X.   Gedmatch is great website for letting you have a closer look at where on the chromosomes the match is, and for seeing who else on their database matches at that position. Gedmatch doesn't have a fee, but accepts donations.

[clairec666]

Sounds strange... I'd imagine there's a glitch in Ancestry's DNA-matching algorithms... your father-in-law should be a match for Person X, but for some reason the match fails to show up. That's the best explanation I can come up with

[hurworth]

I don't think there is a glitch.   I  don't think the way Ancestry presents your matches and how they match is very useful though (another plug for Gedmatch....you can upload your data from Ancestry to there).

This is all part of the fun and challenge of using DNA for genealogy purposes. 

If I had identified some ancestors in common on a tree I would have initially thought exactly the same and assumed this match must be via the father as this matches the tree.   Infact, this makes me realise that I have made some assumptions in our family and without testing some other cousins I really cannot be certain.

If this DNA match was via the father-in-law then he would match.

[RichardK]

Thanks all - glad I'm not the only one puzzled by this.
Richard.

[RPaine]

Dna cannot skip a generation but flaws in a parent’s testing scan can make it appear so. A flaw can make it appear that there is a false break in a person’s segment, which leaves the two segments too small to read as a match.

Another possibility is that the computer can falsely read a short maternal and a short paternal segment as one segment, a match shows for the child but may not show for either parent. This is most common for small segments especially if the parents share an ancestor in the last few hundred years. (My sons have this issue because my wife and I have turned out to be 10th cousins with a pair of shared ancestors in 1593.)

People who ask about the X-chromosome show know that the X-chromosome requires some special understanding because of the special recombination pattern, inheritance pattern and because a male only has a single X-chromosome while a female has two X-chromosomes.

RPaine