Abnormally high cM for extreme distance matches (Cannaday lineage)

[goldfinch99]

Thanks David.  That also shows how the ProTools could help by using the chromosome browser on all these matches.

Colouring in a chromosome browser is on my 'to do' list.

[David Nicoll]

Hi,

     I don’t think that Pro Tools has a chromosome browser at present.
     But you can do quite a lot of useful analysis by grouping DNA matches using the labels in Ancestry.
     Using something similar to the Leeds Method or some other similar clustering method.

[goldfinch99]

Oh, that's disappointing, hopefully A will bring out a chromosome browser soon.  Still worth having a look at the tools, maybe a little Christmas present to myself.

I'm not familiar with the Leeds method or clustering.  I will have to look them up.

[Glen in Tinsel Kni]

I genuinely wouldn't worry about the Leeds method, it can be a lot of work trying to filter matches to four groups with each connecting to just one specific grandparent and is best tackled with matches between 90 and 400cM. Scanning through the posts it seems the matches fall below that amount in many cases. Additionally if there's a chance of pedigree collapse then the odds are people will be related to each other in multiple ways and Leeds Method grouping really doesn't work well when multiple relationship complications are added into the mix.

Ancestry have repeatedly cited privacy issues as the reason for not offering a chromo browser though it obviously hasn't stopped them introducing protools which I'd argue is potentially a bigger privacy issue.

[goldfinch99]

Thanks Glen.  Yes, these are going to be very, very distant confluence points, and the US lines are clear.  On the UK/Ireland side, the only names I've seen are my dad's close relatives on my nan's side.

I think the higher US matches are about 20-25cM, with individuals on the Cannaday line taking up about 4 positions in about the 8th generation past.  It's obvious looking at the US trees that go far enough back, or where a descendant on one of those lines has a name that stays in my memory as I've seen it so often that I know it comes from that lineage.

It's a thing of interest in my DNA.  I saw either an article or YouTube video headlined something like "Think you're descended from Scottish kings?  Think again" and that made me doubt that this could be real.  So I just wanted knowledgeable opinions on how likely this was to be real.

It's cool, I think.  It's like they say about so many people with Euro or Brit ancestry descend from certain key figures in history, but you're not going to find a DNA segment in your ancestry results connecting you to those figures.  Except that it's possible that here's a rare example where it does show in the results for a small fraction of the descendants who have have trees with enough pedigree collapse or endogamy. wow!