Wednesday, 12 October 2016

Chromosome Map review

Time to see if I'm progressing.

"Progress" here is defined as having formed all my segment matches into groups, and hopefully assigned to a "side".
This assignment is either directly because of a match to a known relative at the same position on a chromosome, or by deduction via a lack of a match to the known relative, at the same position with the smaller segment matches checked at where possible.

Last review was back on the 8th  of January (see "How far have I got?"), which chromosome map took all segments of whatever size (usually down to 10cMs).
This time I restricted myself to those 12cMs and above - on left - with the Jan 2016 version on the right
Lorna's Paternal/Maternal chromosome map, Oct 2016
Lorna's Maternal/Paternal segments, Jan 2016

So why am I doing this (I need to remind myself of this every so often!)?
To find those segments that I (or my other tested cousins) potentially inherited from the brickwall ancestors* that got me/us into DNA testing in the first place.
That pretty picture has yet to be produced, but those are the segments I should be focussing on to work with the matches at those spots to find any commonality for hints as to further research into  potential connections.

* the main brickwall ancestors are listed on the 8th January post linked above

There's a very satisfying decrease in the yellow ungrouped, Group A and Group B segments, primarily because of an increase in tested relatives who are starting to pop out of the woodwork faster than I can keep up these days.
The yellow bits are generally singletons - no other matches at the spots concerned to be compared against, but large enough not to be Identical by State (IBS) aka simple coincidental arrangements of DNA that "matches".
The latter two (A and B) are those matches that have been able to be grouped into segments definitely sharing a common ancestor, somewhere/somewhen, but with no ability to compare against known relatives at that spot.
This could be either because none of the known relatives match at that spot, or because different testing companies were involved with no ability to compare at

If you have tested autosomal DNA at any of FamilyTreeDNA (their FamilyFinder test), or Ancestry or 23andme, PLEASE consider maximising your investment in DNA testing by uploading your resulting file to
It has a wonderful range of tools and gives us all the ability to run comparisons to find matches tested at the other companies. All of which helps all of us find our shared ancestry.


  1. Hi Lorna, Just ran across some of your postings. Archibald Henderson and I share 16 novel variants and zero known SNP differences. My haplo for the moment is R-FGC10117. My father's mother is the line with all our Hendersons in it, and in fact I probably have several different Henderson lines through her.I have not got a clue how I relate to Archibald. My surname is Mitchell and almost all my Ydna hits are Campbells! My Mitchell line stops with Joseph Mitchell born circa 1791 in North Carolina, USA. I suspect his people came through Antrim Ireland to the USA.

      shows that your branch and my Hendersons "meet" around 1800 years ago chickleboodie.
      I had to look up the FTDNA Haplogroup tree to figure out where R-FGC10117 is, but it is a different sub branch from L1065 than "ours".
      So the zero known SNP differences would appear to be a bit misleading.

      Make sure you get your BigY results to Alex WILLIAMSON for his BigTree ( and your BAM file to for further analysis.

  2. Henderson is indeed a big surname so I am not surprised we are probably distant. My Hendersons mostly ended up around Palestine, Texas with a few buried in Brushy Creek, Anderson, TX.