This was a concept I wasn’t entirely familiar with, the idea that someone’s STR data set could be so rare that you don’t match anybody. This was striking enough I started looking for ways to measure rarity, and found this link. On this site, they have a spreadsheet you can download, and I fed my Dad’s Y67 values into this sheet. Results were interesting enough, to say the least.
One of the rarity measures is called a Wheaton Average, and I calculated this for my Dad’s YDNA. At 12 markers it was 28.7, at 25 it was 22.7. At 37 it was 16.4, and at 67 it was 11.1. Looking at the chart, in order that would mean, Rare, Rare, Uncommon, Average.
This is the deal. Rare at 12 means rare, period. Same with 25. And if someone can’t begin to match you at Y25, it’s not as if the match gets any better at 67.
This article by Roberta Estes (back in 2012, so with a much smaller pool of tested folks) is illuminating. She says,
The average person has about eight hundred 12 marker matches, just under 200 25 marker matches, fourteen 37, thirteen 67 and not quite one 111 marker match. There still aren’t a lot of folks who have tested at the 111 marker level. The good news is that if you have a 111 marker match, it’s generally a very solid genealogical match. Most people use the 111 marker test to resolve 67 marker matches or to find line marker mutations within a family to identify specific ancestral lines.
To make the point, my Dad and I have 9 matches at Y25.