L1358 Discovered in Group B Walk Through the Y
As all of you know by now (but some future readers might not), our sponsorship of Jerry’s “Walk Through the Y” was successful in the discovery of a brand new, never before identified mutation on the Y chromosome called L1358. The schematic shown below is from Thomas Krahn’s Y Chromosome browser showing the precise location of our discovery as denoted by the red vertical line. As some of you may remember the Y chromosome is about a third the size of the X chromosome and along with chromosomes 21 and 22 among the smallest. But it is still power packed with over 50 million base pairs.
On average a WTY tests about 230,000 Base Pairs. Since FTDNA began doing WTY only about 500 men have been tested and in that 5 year period nearly 1,000 new SNPs have been discovered at FTDNA. In the beginning more SNPs were found because the areas had not been well explored. Of the 500 WTY tests the vast majority (200+) have been for Haplogroup R (which just happens to be the most prolific Haplogroup in England). Of those only 8 were L2+. The last L2+ prior to Jerry’s test was in May of 2011 and no new SNPs were found.
Why is this discovery important? Each time there has been a mutation on the Y chromosome only the descendants of the man in which that mutation took place will carry that SNP. So each man will carry a “genetic roadmap” of his descent from the earliest man. When we find a new SNP it needs testing to determine how widespread it is. If only a few Wheatons in Group B carried this SNP we would know it is very recent. If all Wheatons (and those that match them) carry the SNP we would know it is further back. If other L2+ men test positive then we can place it in a time frame and determine not only who is related to who more recently, but also where the mutation likely occurred. Currently we believe that the man in which the L2 SNP occurred lived in the mountains of Northern Italy about 5,400+ years ago. From that one man the L2 SNP has spread out to Southern Italy, Germany, Belgium, England, Ireland, Scotland, Wales, US, Canada etc. If we test L2+ men for L1348 and find it extends beyond the Wheatons but is only found in England we can start to determine the time frame and likely place of residence of that man in which the mutation first occurred.
This is how individuals working with scientists are changing our understanding of the human family. It extends our ability to reach back beyond genealogical time. In the future with more SNPs being discovered and some of them being more recent…. we may be able to recreate a family tree going backwards via STRs and coming forward using SNPs. SNPs are copying errors where an allele changes from its ancestral value to a derived value. The derived value in this case is A+. Which seems very appropriate! A+