Expanding Paternal & Maternal Matches for Autosomal DNA Tests

[4b2]

Ancestry lists whether a DNA match is paternal, maternal, both sides or unknown. They note that the ones that are unknown may be assigned to a line in future updates. So, I suppose this system is a work in progress.

Does anyone know if it would be possible to expend that to four grandparents or more? i.e. you would have groups of matches for grandparent 1, grandparent 2, grandparent 3, grandparent 4.

[phil57]

That would depend on what Ancestry might decide to do in the future, but I suspect is doubtful. The process involves an algorithm comparing segments of your DNA with those of other matching tests and allocating them to parental sides through further examination of family trees which contain common ancestors (the latter similar in some ways to the Thrulines methodology).

Ancestry doesn't know which parental side is your paternal or maternal side until you have told them when accepting matches.

As they state on the DNA match page, for 9 out of 10 people, the results are expected to be about 95% accurate. For the other one in 10, they may be less than 95% accurate.

Attempting to split the results further would certainly result in a lower accuracy across the board even if it can be considered feasible - and only Ancestry would know whether that could be possible, bt I suspect for the foreseeable future they will be continuing to refine their current methodology.

[Biggles50]

I have found it pretty accurate for me.

Yet it is kind of dumb in that it shows people who are unassigned yet they Share Matches with others who have been assigned to a specific parent.

They still show as unassigned even when I have them linked into my tree and they are set in the View In Tree feature, I can be specific a 90cM 3C in my tree shows as Unassigned.  In my Wife’s matches of the four shown today, two are already in her tree and Ancestry presents them as Unassigned but this section is now showing Pending Update so changes are afoot.

I have not found any pedigree collapse evidence, its worth using the Gedmatch tool “are my parents related”.

There system is very much a WIP and hopefully can only get better.

[melba_schmelba]

I have not found any pedigree collapse evidence, its worth using the Gedmatch tool “are my parents related”.

With the caveat, as always, that GSA kit (23andme 2017-, FTDNA & MyHeritage 2019-) matches are unreliable at high cM levels on GEDMATCH, let alone 3-7cM ones which might turn up fairly frequently between random Brits anyway .