Saturday, August 9, 2014

Unraveling BIG Y Test Results: R-S1026

For a long time I have been stymied in my efforts to trace my SNP trail through the most recent three or four millennia down to genealogical time. Now we are beginning to make some headway due largely to the herculean efforts of the citizen scientists of the R-L21 and subclades project. The BIG Y, Full Y, Chromo2 and other discovery tests are providing multiples of the numbers of SNPs that had been identified prior to the beginning of 2014. 

R-L21 is the most prevalent male haplogroup along the western coast of Europe. In some areas it approaches 80% of the male population. Therefore, knowing that one is part of this mega clan is interesting but not very useful genealogically speaking. I had tested positive for DF13 which is a SNP just below L21. This still is not that useful as the vast majority of R-L21 men also belong to this subdivision. A dozen subclans of DF13 have been discovered in recent years but one by one I had tested negative for all of them prior to getting my BIG Y results. Now I know that I belong to the newly identified S1026 subclan. Below are the results of nine of us who have BIG Y results: 
This chart lists the SNPs for each of us that have been discovered downstream (toward the present) from S1026. At least six men have been identified by the Chromo2 project at ScotlandsDNA. 

My results are those in the middle column above. The man whose results are my closest match in the SNP chart above (just to the right of mine) is a sixth cousin-once removed. He and I share 105 of the 111 short tandem repeats (STRs) over which we previously had been tested. We appear to share five SNPs that so far separate our migration trail from that of any of the other members of this emerging group. He and I share a common ancestor who died in Southern Maryland in 1733. Even more recently I have four additional SNPs and he has seven.

The McDaniel man represented by the SNP trail in the column to my left above is my next nearest relative in this grouping. He and I previously had discovered we shared 35 of 37, 64 of 67 and 102 of 111 STR markers. He has seven identified SNP mutations since his ancestral DNA trail separated from mine and that of my Dowell cousin. The three of us share nineteen additional so far identified SNPs in common before our common trail merges with that of the three men in the columns to our right. Then the six of us share five earlier SNPs before we converge with others with whom we share SNP R-S1026.

It is going to take test results from additional men to sort out the exact sequence in which all these SNPs should be arranged chronologically. For example, we know that the five SNPs recently named (see chart above):
Z16886 Z16887 Z16888 Z16889 Z16890
are grouped together but we don't know in what chronological sequence they occurred. Only as more are tested and some are positive and others are negative will this more precise arrangement be possible. This sorting of other SNPs which are lumped together above will follow a similar process. As a result the SNPs will appear to be out of sequence as their correct ages and thus their actual locations along the migration path of our paternal DNA begin to appear. This will result in the nice orderly naming progressions to be scrambled.

Isn't genetic genealogy fun? The more we discover the more we have yet to learn. 

No comments:

Post a Comment