Author Topic: Chromosome shared segments query  (Read 1043 times)

Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Chromosome shared segments query
« on: Thursday 01 February 18 06:12 GMT (UK) »
I am looking at two of my matches and our shared segments on the FTDNA Family Finder Chromosome Browser and would be grateful for some help.

They are both predicted to be 2nd to 4th cousins. I know that "N" is a second cousin once removed, but I have no idea how "P" and I connect.

These two matches do not match each other anywhere so my relationship with N and P must be on different branches of my family.

The matches with "P" are quite significant I assume? They are as follows:

PB matches you on chromosome 10 from position 24868750 to 49437552 for a total of 18.64 cM.
PB matches you on chromosome 10 from position 55717476 to 89348652 for a total of 35.79cM.
PB matches you on chromosome 10 from position 119223365 to 127738898 for a total of 16.63 cM.
PB matches you on chromosome X from position 38886494 to 41030869 for a total of 5.71 cM.
PB matches you on chromosome X from position 147012373 to 149379258 for a total of 5.26 cM.

Can someone please explain the significance of the matches on Chromosome 10? And the X matches?

Just for comparison, these are the matches I have with "N" my proven second cousin once removed:

N matches you on chromosome 1 from position 5601705 to 9016716 for a total of 5.67 cM.
N matches you on chromosome 4 from position 54662466 to 61361342 for a total of 7.77 cM.
N matches you on chromosome 9 from position 86674433 to 94909764 for a total of 13.5 cM.
N matches you on chromosome 18 from position 72872188 to 76116152 for a total of 11.97 cM.
N matches you on chromosome 19 from position 44647355 to 63788972 for a total of 45.71 cM.

Can anything be gleaned from these chromosome positions? I am guessing if I can't find a paper trail, there is nothing in these numbers that will help me?

Thanks in anticipation.  :)



RootsChat is the busiest, largest free family history forum site in the country. It is completely free to use. Register now.
Also register instantly with Facebook or Twitter (and other social networks). Start your genealogy search now.


Offline colmc

  • RootsChat Extra
  • **
  • Posts: 46
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #1 on: Thursday 01 February 18 07:03 GMT (UK) »
I don't know if this will be of any help, but I was asking something similar the other day

http://www.rootschat.com/forum/index.php?topic=786693.0

RootsChat is the busiest, largest free family history forum site in the country. It is completely free to use. Register now.
Also register instantly with Facebook or Twitter (and other social networks). Start your genealogy search now.


Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #2 on: Thursday 01 February 18 12:19 GMT (UK) »
Thanks colmc. Confusing isn't it?  :-\

It sounds like you are trying to match up yourself and others to work out where you all connect,  whereas I am just trying to find a match with myself and one other person who seems to match a large amount on Chromosome 10.

I am hoping someone can tell me what all the numbers indicate, if anything ...

Offline Spike H

  • RootsChat Senior
  • ****
  • Posts: 273
    • View Profile
Re: Chromosome shared segments query
« Reply #3 on: Thursday 01 February 18 20:59 GMT (UK) »
Ruskie, not much can be read into the position you match on.
Have you run PB and N through the In Common With function?
Re X matches - anything under 20 is considered  most likely a false match.
UK: Lee, Swift
CON: Davey, Harding, Hocking, Rule, Whinnen
AUST: McIntosh

Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #4 on: Thursday 01 February 18 22:04 GMT (UK) »
Thanks Spike.

I just had a look at the "in common" function. PG only matches one other person, a 5th to remote cousin, so I don't know how useful that is?

"N" has 19 matches. :-\

What do these matches tell me?

I will dismiss the X matches as red herrings.

Offline Spike H

  • RootsChat Senior
  • ****
  • Posts: 273
    • View Profile
Re: Chromosome shared segments query
« Reply #5 on: Thursday 01 February 18 22:11 GMT (UK) »
19 is good!
Now you put them in the Chromosome browser - five at a time it allows - and see which ones match N on the same segments that you match with N.
UK: Lee, Swift
CON: Davey, Harding, Hocking, Rule, Whinnen
AUST: McIntosh

Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #6 on: Thursday 01 February 18 22:29 GMT (UK) »
I just did that with PB and the one other match and there seem to be no matches at all.

I will look at N's matches now. :)

Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #7 on: Thursday 01 February 18 22:46 GMT (UK) »
I have only compared 5 so far.   :)

Two of N's matches match on chromosone 6 - one 8.79 cM and the other 9.29 cM.

I am a bit confused. Do these two matches only match with N? Do I need to match on the same positions to find a link?

I will compare the others ...


Offline Ruskie

  • RootsChat Marquessate
  • *******
  • Posts: 21,869
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Chromosome shared segments query
« Reply #8 on: Thursday 01 February 18 22:53 GMT (UK) »
Similar with another two matching on similar positions on chromosome 2 - one 11.05 cM and the other 9.21 cM.

And again on 19, one 10.05 cM and the other 9.55 cM.

No more matches/overlaps with the other people N matches with.  :-\

I think I will keep playing with the "in common with" function to see if I can discover more.