Ancestry ThruLines - disappearing cousin

[RoseJA]

Firstly, just want to thank Peter for the Zoom talk he gave on DNA yesterday (Sat 4th Feb). Nice to put a face & voice to the name. I was relieved to find that a lot of the things Peter mentioned I have come across in my own research. I thought I had been getting the hang of things but I recently noticed something different about my Ancestry ThruLines which puzzled me, or rather I think a recent Ancestry update may have confused the issue. Let me explain:

When I received my DNA results over a year ago I found a maternal-side first cousin & her daughter topping my list of matches. Weighing in at 847cM and 427cM shared DNA respectively, they fitted nicely within the parameters as given on a relationships chart in Peter’s masterclass. If my cousin popped up in Shared Matches (with or without her daughter) I was confident the other matches would be on my maternal side. Both cousin & daughter appeared in my maternal grandparents’ ThruLines. The technology worked.

I suspected that Parent1 was my maternal line – there is a chunk of Irishness appearing in my Parent2 which suggested this was my paternal line. My thoughts were confirmed with the introduction of SideView and the Maternal/Paternal/Unassigned/Both Sides labels. Again, thumbs up for the technology.

I noted that Ancestry applied the Both Sides label to my first cousin. Since Peter had written in a newsletter this could happen with close family I wasn’t too worried – I put it down to cousin’s mother’s family coming from the North London area. My father’s forebears had converged on North London during the 19thC so I figured there could be a dash of common DNA in the melting pot. The cousin’s daughter was not labelled as Both Sides so I assume the segments of DNA causing Ancestry to apply that label had not been passed on. On one occasion, when using Shared Matches, I came across my cousin and someone labelled as Parent2 – looking at this Parent2 person’s tree I saw surnames and locations which made me think they were more than likely on the Parent1 side. So I’m getting a bit confused now.

I labelled my cousin as Maternal – at one point I reset the labels back to Parent1/Parent2 and Ancestry today tells me my cousin is still Parent1, it’s not trying to tell me she’s Both Sides.

However, just before Christmas I was having a look at ThruLines and had a “What’s wrong with this picture?” moment. I noticed my cousin’s 847cM seemed to be appearing less often than previously, but her daughter was still appearing in all the places I would expect. Mother and daughter both appear in the lines emanating back from my grandmother BUT only the daughter is appearing in the ThruLines going back from our grandfather. My cousin has disappeared from our mutual grandfather’s lines. My initial reaction: “was my uncle illegitimate”. But a look at granddad’s WW1 army record showed that he was back in Blighty in 1918 and absconded from a hospital for a few days (back home, perhaps?) – the timing is tight but nothing so out of kilter to make me doubt he is the father of my cousin’s father (born in 1919).

Having pondered things, I wondered if something could have gone awry at Ancestry’s end. DNA passes down generation by generation, it can’t skip a generation, once it’s gone it won’t reappear. For argument’s sake, if my uncle was illegitimate then it makes sense that my cousin would only appear in grandma’s “back catalogue” of ancestors. However, if there was no DNA from our granddad then not only would my cousin not appear in granddad’s lines then neither would her daughter, yet the daughter is still appearing in both lines. As stated above, both cousin & her daughter appeared in the ThruLines of both my maternal grandparents for months yet it is my cousin who has disappeared from granddad’s line.

Thank you for reading this far – as much as anything this was to help me get my thoughts in order. Things have gone from making sense to now not making sense. I appreciate Ancestry’s processes can’t give 100% accuracy.

Is this likely to be down to an Ancestry “refinement” going one step too far and confusing the issue? I’m hoping that a future update from Ancestry will reinstate things (like it did when my Germanicness disappeared from my ethnicity results only for it to reappear in a later update). Or have I overlooked some other explanation?

Kind regards,

Rose

 

[Katie Bee]

I know Thrulines uses member's family trees to sort out what it thinks the relationsips are.
Could your cousin have deleted her family tree and this confused Ancestry?
I realise that she would still be in her daughter's family tree, but Ancestry may be fooled momentarily.
Hopefully Peter, or someone else, will have an explanation and Ancestry will reinstate her at a future date.

 

[RoseJA]

Thanks, Katie. My cousin's tree (small as it is) is still available on Ancestry. I know that Ancestry uses members' trees to work out likely common ancestors.
My cousin has not disappeared from our trees, she's just not appearing in the matches displayed against our grandfather & his ThruLines - leading to Ancestry suggesting she is my half-cousin if I click through from our grandfather & his lines, but full cousin when clicking through from grandma & her lines. I assume that the daughter appearing against both grandparents has proved that there's no hint of illegitimacy! (Not a conversation I want to have!)
I suspect a glitch somewhere, and there must be others who've had strange things happen, I just hope it will sort itself out - it was quite disconcerting when I first noticed it.
Thanks again.

 

[Stuart]

I have several cases where ThruLines/Common ancestors says a match is a half cousin and I know it's a full one. I think that's down to how Ancestry join trees together.

They have to decide that a person in one tree and a person in another tree are the same person. Obviously they have to have rules about how many facts have to match, and how closely (e.g. for dates). (If the lines in the trees overlap for several people, the rules can get quite complicated.)

For full cousins the common ancestors are a couple, for half cousins just one person. So if the join is made at the common ancestors, and one of them meets the "is it this same person" test and the other fails it, they would turn your full cousin into a half cousin. They just haven't recognised one the parents as the same in both lines of descent.

 

[RoseJA]

Thanks for replying, Stuart,
Sounds like it is a problem with a recent update - Ancestry had got it right first time!

 

[John Dancy]

I have found that where my full cousins are shown as half cousins it is quite often because, either the DNA match it is linking me to has a different parent shown or the same parent with a different spelling for their surname, or one of trails has the first downward link with two possible parents in one of the matching records. As the cousin might not have taken their tree back this far it can be difficult to correct, even if you complete the branch in your own tree. Where it is my own error I correct it.

 

[John Dancy]

Checking my Common Ancestors later I find a new one with my direct line having a 'half sister' - Where in real life William Johnson and Eliza Clements (as far as the GRO are concerned) had a daughter in 1841 called Eliza, her three associated trees selected by Ancestry have her mother as Eliza Burrows (who doesn't appear anywhere on the GRO as a mother in that quarter) I suspect that the trees are copies of the same information.

 

[RoseJA]

Thank you, John,
so it looks like there are reasons why the "half" keeps roving in and out (I've noticed other areas where someone who was labelled as a half-cousin has been updated to full status) - other than illegitimacy/descent from a 2nd marriage, for example.
But I am still mystified as to why, when looking at my list of direct ancestors on the main ThruLines page, my cousin's 840cM--odd does not appear in the matches of my grandfather & his ancestors but her daughter's 420cM-odd does. When I first had my DNA results both cousin & daughter were displaying as matches under both my maternal grandparents.

I shall await a further update and see what that does!

 

[RoseJA]

Further to this message strand from Feb2023, I will just give an update:
In Aug2023, I noticed that my cousin was back in ThruLines, with her daughter, for both our grandparents but cousin was still showing as half-cousin in one grandparent's ThruLine - an improvement but not quite there. Today I just looked at ThruLines again (for the first time in a long time) and, wonder of wonders, both my cousin & her daughter are not only showing up in both grandparents' lines but both are labelled as full cousins. So finally back to where they should be, i.e. where they were over 2 years ago when I first got my DNA results. Hooray. Just wondering how long it will stay that way, and whether things will change again after the next Ancestry update...

I had another conundrum crop up with a relationship suggested by Ancestry - don't worry, I won't bore you with the details - at first things made sense. More importantly, it seemed to confirm that a presumed great-grandfather was the biological father of a grandmother. Within days, the suggested relationship had changed slightly to something that did not make sense, although still linking back to the correct family (so I'm hoping the confirmation still stands - I dread looking again in case it tells me something else).

Ancestry's systems appear to work well but when they get things askew I find it rather disconcerting. But I suppose it makes things interesting.