Friday, 6 March 2020

New Results for the Mayo O'Malley's (Group 3a)

Some new Big Y results have recently come back from the lab that add to our understanding of the evolution of the O'Malley surname in Mayo.

Project Member WM-7732 * had already been provisionally placed in Group 3a (the Mayo O’Malley’s), but his Big Y results show that his “Terminal SNP” is now defined as FT86146. This places him on a very specific downstream branch of the Tree of Mankind and allows us to see how closely related he is to other men in the O’Malley DNA Project, specifically Group 3a - the Mayo O’Malley's.

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Below is the SNP Progression for FT86146. A SNP Progression is simply the sequence of SNP markers that characterises each branching point on the Tree of Mankind, starting "upstream" at the level of the Haplogroup (R in this case) and progressing all the way "downstream" (i.e. towards the present day) to the Terminal SNP. Think of this string of SNPs as a line of ancestors coming forward in time towards the present day. Comparing the SNP Progressions of two branches helps us see exactly where each branch sits on the Tree of Mankind relative to each other and this tells us how closely or how distantly related are people sitting on these respective branches. The SNP Progression for the FT86146 branch is as follows:
  • R-P312/S116 > Z290 > L21/S145 > DF13 > Z39589 > DF49/S474 > Z2980 > Z2976 > DF23 > Z2961 > Z2956 > M222 > Z46375 > DF106 > DF104 > DF105 > BY35731 > BY35730 > BY35759 > FT86146
To give you some idea of dates, P312 (in bold above) appeared about 4500 years ago, M222 about 2700 years ago, and DF105 about 1900 years ago.

The overarching DNA marker for the Group 3a O’Malley’s is BY35730 - most people below this SNP marker bear the O'Malley surname (or one of its variants), and most of them have roots in Mayo. Using SNP counting, the BY35730 branch appeared about 1000 years ago (1000 AD) - around about the time that surnames started being used in Ireland. BY35759 branched off about 850 years ago (1150 AD), and FT86146 arose about 650 years ago (1350 AD). So we are slowly expanding this branch of the Tree of Mankind and moving forward in time towards the present day ... this will continue as more people join the project and do the Big Y test.

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His nearest Big Y match is project member JM-1989.* This member has 8 Private Variants (i.e. unique SNP markers not shared with anyone else in the database … yet). In comparison, WM-7732 has 6 unique SNPs, which currently don’t have names, only numbers marking their location on the Y chromosome - 4640162, 7528251, 8781458, 9640659, 13606699, 19464511 (see diagram above). So between the two of them, they have an average of 7 Private Variants (unique SNPs) which suggests that they share a common ancestor about (7x84=) 588 years ago (so roughly 1400 AD).

This Time to Most Recent Common Ancestor estimate (TMRCA) is reflected in the STR results for WM-7732. He has 1 match at the 37-marker level of comparison, 10 at the 67-marker level, and 4 at 111 markers (2 pairs of cousins - see below). His nearest Big Y match JM-1989 appears in his list of matches at the 67-marker level but drops off the list at the 111-marker level, because his Genetic Distance is 11/111 which is just above the threshold for being declared “a match” at that level of comparison.

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The TiP Report provides TMRCA estimates based on his STR data. All project members have access to this tool (the orange TiP icon above) but only for your listed matches. As Admin, I can use the tool for everyone in the project. Using this tool, the midpoint (50%) TMRCA estimate for WM-7732 and JM-1989 is 12 generations which roughly translates into a birth year of about [1950-(12x30)] = 1600 but with a 90% range of about 6-20 generations = 1350-1770 (so you can see that these estimates are really very crude indeed). 

Still, the STR-based TMRCA estimate falls roughly within the same time period as the TMRCA estimate using the SNP counting method above, and so we can be reasonably confident that the common ancestor probably falls somewhere within the 1400-1600 time period. Hopefully the methodology behind these TMRCA estimates will improve over time and will allow more granular estimates with narrower ranges.

Nevertheless, the 1400-1600 time period would be around about the time that Grace O'Malley lived (c.1530-1603) ... but did she sit on this same sub-branch, or some other adjacent branch? That's the question we still need to answer!

The Big Tree version of this portion of the Tree of Mankind contains a lot less information than the screenshot taken from FTDNA’s Big Y Block Tree above. This is because not everyone has submitted their data to the Big Tree. All project members are encouraged to do so as the excellent folk at the Big Tree provide some additional essential analyses (for free) that can prove very helpful indeed. Instructions for uploading your Big Y results to the Big Tree are here …

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The next step will be to create an even larger version of this branch of the Tree by including those members who have not done the Big Y test - they can be placed provisionally on the Tree by using their STR data, but such placement is only tentative and firm placement can only be achieved by Big Y testing. I hope to post a separate blog about this expanded “family tree” for Group 3a in the near future.

Maurice Gleeson
March 2020

* the project member’s unique ID consists of his initials followed by the last 4 digits of his kit number.

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