The President of FTDNA's discussion on the value of SNPs is one of the best I've
heard. You can listen to it here at "Sinclair DNA and Bennett Greenspan, Founder
of FTDNA" from 04/14/2011.
About ten minutes into the discussion, Greenspan, spends about seven or eight
minutes discussing SNPs versus STRs and the Y DNA family tree. Here are some
Bennett Greenspan said:
"Think of it (Y DNA phylogeny) as a tree, then you have a branch, and then you
have a twig and at the vary end of the twig you have leaves...
when looking... at our markers we are looking at our leaves...
The leaves are the STRs so the STRs have a much higher mutation rate than the
SNPs. Also the STRs can get bigger or smaller...
and because they can go one direction and keep going or and turn around come
back to where they were, there is always a little bit of gray...
because of that the other biological item we can use is this branch or this twig
called a SNP because it moves one direction and is not believed to move back, so
consequently it's stable...
The question is how those leaves connect to many twigs which all fit onto the
same branch and we are working on trying to close a time gap from the leaves
work for ... for the least three hundred or four hundred years, maybe it'll be a
little bit further than that with 111 marker tests...
however, if we can discover the twigs, all the twigs on a branch, then we won't
have that uncertainty that the Y STRs provide, because they are not perfect, but
if can we look at these twigs they are all defined by whats called a SNP, which
is a single mutation that happened one time in our species and all of the
descendants of that person who had that that mutation will have that mutation,
in that way we can bridge the gap between genealogy and anthropology which takes
us back thousands of years...
what's happening now in this explosion of new twig discoveries on the tree...
and so it's not going to take all that long, my expectation is that within a
couple of years it should be mapped out in enough detail that we'll have
connected the twigs and leaves in enough detail...
There should be great geographical specificity between individuals when we can
do that." [end of Greenspan quote]
This is an exciting time! We are seeing our ancestry tree unfold to great depth.
SNPs will help from one direction and STRs and genealogical records will help
from the other.
A few years ago most European men were either Ht15 or Ht35, related to the identifiable two types of R1b.
Look at FTDNA's current working draft version of R1b's descendancy tree.