DNA matches and thrulines

[kylejustin]

can i ask this thread stays on the general forum and not be moved to the DNA section please? as i feel it's more thrulines related than genetics.

when you match DNA with others on ancestry, it now attempts to tell you who the common ancestor's are. generally this comes from matching ancestors in yours and your matches' trees.

i have noticed tonight, that it is telling me names of common ancestors when the matches don't even have them in their tree...sometimes the match goes back to a generation or two down from the common ancestor.

i saw one example where i matched a lady in her 90's, and her grandson. the grandson only had grandparents on his tree, yet it told me the match was late 18th century.....when i looked at thrulines, it showed him as a grandson of the other lady, and her tree went back to the common ancestors.

so ancestry is filling the blanks using family trees as a whole to state how you are related, even if your matches don't have the common ancestor's in their trees.

i also had an odd match. the common ancestor is given as mary butler (1773-1862), which is strange as it's always a couple listed. and i have 9 matches descended from her. the thing is, i don't have this lady or her family in my tree....now mary butler married edward poole, and they come from tetbury, gloucestershire. it's saying she is the mother of my thomas poole (c.1807-1833), and her children are listed in thrulines as half siblings of thomas, 5 of them. now edward and mary did have a thomas, and i do suspect he is my thomas, and have for years. except the poole family is exceedingly large with many matches, and a canadian family believes they are descended from this couple's thomas.

i find this strange and a little worrying. the idea is to match existing information in trees. if you or your match doesn't have this information, who's to say ancestry is correct? even with all these matches to one poole family, and many from edward's brother, i still can't work out how my thomas fits in. i don't like the idea that ancestry is trying to tell me.

has anyone else noticed anything strange like this?

[Anne in Carlisle]

Yes, Ancestry computes ALL its trees, including private ones, and comes up with common ancestors to suggest to you formed by bits from different trees.

I have used these as guides a lot in adding DNA matches to me and the other tests I manage. In my experience Ancestry's suggestions (obviously they have done NONE of the work except run algorithms!) are about 95% correct. The others are works of fiction! Some of the correct ones seem to only identify one of the couple of common ancestors and match the relationship as 'half 4th cousin' or similar. I have not been able to discover why. Sometimes they are really half cousins but often they are not. I then list their relationship correctly in their headline.

When I add a DNA match (either through the 'common ancestor' route; by finding names in common on their trees or just getting lucky with unusual names and help from BMD) I always build a proper records based tree for that line to make sure I am satisfied as much as possible that it is all correct. I have been pleasantly surprised to find so few Ancestry suggestions are rubbish.

Anne

[GallowayLass]

Just a thought - as ancestry Thrulines are based on the complete database of ancestry members’ trees (public and private) and not DNA, there’s every possibility that people who show up as relatives in Thrulines are in the trees of members who have built their tree but not taken a DNA test?

[Anne in Carlisle]

Just a thought - as ancestry Thrulines are based on the complete database of ancestry members’ trees (public and private) and not DNA, there’s every possibility that people who show up as relatives in Thrulines are in the trees of members who have built their tree but not taken a DNA test?

Yes, I believe so. Some of the trails I have followed have evidenced multiple bits of different trees as so called 'proof'. Those tree owners most often do not match me and don't all have the complete picture. It is only by making my own tree for that particular line that I am satisfied.

One of the worst bits about the suggested common ancestors is the interpolation of ancestors further back than those I already have. I usually dismiss those because they are either too difficult to prove or to far back in time to have a meaningful DNA link. However I have made a couple of breakthroughs.

Anne

[Anne in Carlisle]

kylejustin. On your particular point about your Thomas you do have to be careful if there are a lot of people of the same name in an area. My father's family are ALL from Bedfordshire, a very small county and Ancestry has given me a few suggestions which I can actually prove not to be correct. BUT that leaves the mystery of exactly how the DNA connects you to all those people? In the case of Bedfordshire I think there must be some common DNA from close family relationships amongst a few villages with a number of families with the same surname. I have a good number of DNA matches that all point to the same small area of Bedfordshire but I have yet to find exactly how we connect.

Anne

[kylejustin]

One thing i bear in mind, especially dealing with american trees, is that the DNA is correct and the paper trail isn't.....this can come down to the other person not having the best research or perhaps hidden adoptions or affairs.

this is the first example of suggested ancestors i've come across on thrulines. I suppose ancestry looked at all the matches and their relationships, seeing their common ancestors and decided how i fit in too. I suppose i don't like it as you don't know other people's are accurate. Though i did do several poole match trees and they all matched as descendants of edward poole and mary butler, or his brother samuel. And the matches from samuel were the same relationships ie 4th cousin etc as the ones from edward.....so begs the question if the lineage is from a brother of theirs....the name is rather common in gloucester/wiltshire.