Wednesday, 24 May 2017

Z255 SNP Pack Results - a first look

Last month (April), 14 members of the Gleason DNA Project underwent testing with the newly revised Z255 SNP Pack. FamilyTreeDNA were very quick to process the requests and the results of 12 of these members have already been returned from the lab.

Below are the top-line results of these first 12 tests. Only the most relevant SNP marker data has been extracted below and individual sections can be enlarged by clicking on the image. A pdf version of the complete data can be downloaded using this Dropbox link here.

To orientate you to the table, the SNP marker results of each of the 12 members are arranged in columns B to M. Each column has the initials, G-number, and kit number for each member. SNP markers highlighted in pink tested positive in that particular individual. The various branches of the Mutation History Tree for the North Tipperary Gleeson's (Lineage II) are indicated at the top and at the sides and are coloured in the same colours as in the current diagram of the tree (see below).




So what do the results tell us?

First off, working down the tree from marker Z255, all 12 members tested positive for the following markers: Z255, Z16437, Z16438, and BY2852. All but one person tested positive for BY2853 and BY2854.

Then we arrive at the Gleeson-specific markers, starting off with A5631 - everyone tested positive for this marker, as previously predicted from the results of the 10th Big Y test (from our Clan Gathering Chairman, Michael G Gleeson, 371202). These results came in after the tree diagram below was drawn and effectively confirmed that Branch F (predicted solely from STR data) did in fact exist. 

Below A5631, the Gleeson Tree splits into 2 branches. The first of these branches is Branch F and the first impressive results of the SNP Pack testing have revealed that 2 of the 12 members (G-104, G-97) belong to this branch. Their SNP data has helped define a new SNP block below A5631 consisting of the following SNPs (which up until now were "Private SNPs", present only in our Chairman, MGG-371202): 
  • BY14189
  • BY14193
  • BY14194
  • BY14195
  • BY14197

The other branch below A5631 is characterised by a SNP block consisting of 3 SNPs: A5627, A5629 & A5630. These 3 SNP markers are shared by Branches A through E in the Lineage II group. Ten of the 12 members tested positive for these 3 SNPs ... except for member G-75. His result came back negative for SNP A5627. This could be a back mutation in this SNP, and so FTDNA are retesting this single SNP marker to be sure.

Current version of the MHT for Gleeson Lineage II

Below the A5627 Block, there are two branches:
  • A5628, which in turn splits into Branch A and Branch B ... and possibly Branch E
  • BY5706, which in turn splits into Branch C and Branch D ... and possibly Branch E

From the above, you will see that the placement of Branch E on the current Gleeson Tree is in some doubt. This is because we have had no SNP data available for Branch E up until now and its placement in the tree has been based on STR data alone. Its ambivalent placement became apparent when we ran Dave Vance's SAPP programme using the STR data and this showed that it could equally be predicted to be nearest to Branch B as Branch C - this was discussed in a previous post (Dec 2016). However, a second major benefit of the SNP Pack testing is the revelation of the correct placement of Branch E. 
  • Member G-75 (MG, 371160) from Branch E tests positive for the SNPs BY5706, BY5707, BY5708 & BY5709. 
  • The first (BY5706) is common to both Branches C & D, and the latter three are SNPs that characterise Branch C. 
  • Thus Branch E is now identified as a sub-branch of Branch C.
And on the topic of Branch C, two of the 12 members (G-89 & G-22) tested positive for Branch C SNP markers (BY5707, BY5708 & BY5709). Not only that, but their results effectively split Branch C into 2 different sub-branches: C1, C2
  • C1 - characterised by the SNP A13116 and shared by members G-89 and G-66
  • C2 - characterised by the SNP Block A13110, A13112 & A13113, and shared by members G22 & G71


This new categorisation leaves member G-71 with the Private SNPs A13111 and FGC19590; and leaves member G-66 with the Private SNPs A13114 & A13115.

None of the 12 members tested positive for the SNPs characterising Branch A, Branch B or Branch D.  However ... 
  • 1 member tested positive for A5628 and therefore sits on a new branch adjacent to Branch A and Branch B
  • 4 members (G-81, G-108, G-77 & G-18) tested positive for BY5706 but no downstream markers - they therefore sit on a new branch (or branches) adjacent to Branch C and Branch D
  • 2 members (G-94 & G-110) only tested positive for the A5627 SNP Block and nothing further downstream. They therefore sit on a new, relatively upstream branch (or branches) on the Tree.

In the next post we will look at the revised Mutation History Tree for Gleeson Lineage II, incorporating these new SNP Pack results.

We'll also look at what this SNP Pack testing has told us about the nature of the evolution of the Gleeson surname and how it has helped individual members with their genealogical research.

Maurice Gleeson
May 2017





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