I am about to ask you to help build a library of Y-chromosome lineages, but I am getting ahead of myself.
The year is ending, and 2018 will be here shortly. It is time to set aside the old and build toward the new. It is time for change. It is time to rethink. It is time to realize that a revolution started sometime in 2010 that reached the genetic genealogy community in 2013 has come of age.
It is time to acknowledge that while many of us were popping autosomal DNA tests faster than Pringles®, the Y-chromosome DNA world tilted on its axis, and what we thought we knew changed.
Well, twelve plus years ago when I got started in genetic genealogy we had simple rules.
- The Y-chromosome is the male sex chromosome. It is passed from father to son with only small random changes.
- Y-chromosome DNA testing is the single best test for genealogists.
- Y-STRs were for genealogy. If you had matches, more were better.
- Y-SNPs were for Deep Ancestry that is pre-history and anthropology.
Now, the first still holds. The millions of autosomal DNA tests sold have kicked the second to the ground. The third must be taken with some skepticism. I will talk about that another time. It is the fourth that we must let go of.
The Tortoise and the Hare
We all know the fable of the tortoise who won the race by slowly and steadily plodding to the finish line while the hare arrogantly goofed off and flaked out. In 2010, two population geneticists (the guys who use DNA to study human ancient history and migrations) wrote a paper using it as an analogy for Y-SNPs and Y-STRs. Y-SNPs were slow and steady. Y-STRs were fast but unreliable and flaky.
In The hare and the tortoise: One small step for four SNPs, one giant leap for SNP-kind, Yali Xue and ChrisTyler-Smith studied a well documented pedigree and tested two men who had thirteen generations between them. That is, they were 5th cousins once removed.
The text from figure one in the paper reads, “Two Y chromosomes (from the starred individuals) from a deep-rooting pedigree were genotyped and resequenced. They showed zero Y-STR differences after typing 67 Y-STRs, but four base substitutions after comparing ~10 Mb DNA sequence. Typing additional members of the pedigree allowed these four mutations to be placed on the pedigree in the locations indicated.”
Although the men were exact matches at 67 Y-STRs, they had a total of four SNP differences in the 10 Mb of the Y-chromosome tested.
The academic and forensic community largely dismissed their effort. There were two main objections:
- High quality DNA was needed.
- It was expensive.
That was 2010. Even then, despite the objections, a high-resolution Y-SNP test was the winner for defining and splitting a genealogical pedigree.
The Y-SNP Tsunami
In 2013, Family Tree DNA and Full Genomes Corporation launched NexGen based Y-SNP discovery products. The genetic genealogy community called it a SNP Tsunami and scrambled to keep up with the flow of new results.
For the past four years, we have all learned and adapted. It has been a long and not always bloodless revolution.
The thing though is that it is only beginning. When you have wandered the desert without water, the tiniest stream seems immense and a few drops of rain feel like a storm.
We need a monsoon that regenerates our family trees.
Most who have taken one of the NexGen Y-DNA tests have done it for deep ancestry. A few forward thinking Surname projects have done family lineage testing. What those surname admins have found matches what Xue and Taylor-Smith found.
The time has come for the rest of us to join in. The biggest change of the last four years is that the price has, finally, come down on testing. That means that it is still expensive but possible to do what I am about to propose.
As genealogists and family historians, we need to build a library of Y-chromosome lineages.
Each of us needs to pull out our 5 generation pedigree chart and look at our eight 2nd great grandfathers. Here is my chart.
We need to reach out to cousins and test male representatives of those 2nd great grandfathers and convince them to test their Y-DNA at the Big Y level. We need two representatives of each line. The first representative establishes how the line fits onto the greater paternal tree of humanity. The second representative places the family line with definitive Y-SNPs on that tree.
Yes, I know that I just asked you to Big Y test sixteen men. It is a lot. It needs doing though. It is an effort that will leave not only help our own genealogy research but will leave a legacy for future generations of researchers.
I, myself, and a little overwhelmed by the effort it will take to find the right men to test for my lines.