A haplotype is a group of ancestors who lived long enough in a particular place to generate one or more mutations. Our ancestors lived long enough in and about England that it's clear that we are a part of a very general haplotype called the "R1" haplotype.
A lot of people can trace their ancestry back to this big category that includes Europe and England. But with more research, it has become possible to narrow down this big category, becoming more and more precise about where and when our ancestors were. And instead of the long form of representing haplotypes, there are now (happily) short forms. Instead of our haplotype being represented R1b1a2a1a1b3c1 it is simply L20 (sometimes L-20 or even R-L20).
This is known as "subclade" which is nothing but a subdivision of a larger group. It turns out that the R1 haplotype has many subclades (themselves haplotypes, but more specific ones). A key subclade is the U152 subclade. Another is the L2 subclade which is different from the L20 subclade.
Jim Maule and I both are in the U152 subclade, but he is in the L2 subclade of that (think branch and twig), whereas I am in the L20 subclade of the U152.
Note the last row of the table on the previous posting. "...you are not related and the odds greatly favor that you have not shared a common male ancestor with this person within thousands of years. You are probably even in different Haplogroups on the Phylogenetic tree of Homo Sapiens."
Jim and I are in different haplogroups. He is in the subclade L2 and I am in the subclade L20. That creates a genetic distance which may extend several thousand years. But we are both in the larger subclade U152. This means that we share a common ancestor. But that common ancestor lived several thousand years ago. There is a genetic connection, but it is not recent enough to be helpful in genealogy which only goes back 400 years to the time of George Manly.
But this raises the question of how far back? And where? This is where it becomes interesting again. For example, it is possible to locate approximately when the L20's diverged from the L2's and where. Think of that one individual about 1650 BC. It could well be that he is Jim Maule's and my common ancestor! The time frame is about right "thousands of years" (3,600).
Tibor Feher believes that the U152 subclade began with a single individual living in Northern Italy about 1650 BC. Those who test negative for L2 (as I did) and positive for DYS 492=12 (as I did) are regarded as closest to the U152 line. But the L2s and L20's split here, sometime after 1650 BC.We are U152's, but now distinct.
Over the years, descendents from this individual moved out from southern Europe and are found as far away as Scandanavia. Efforts are now being made to link at least one of these groups to the Celts of Belgium, including the Bituriges. Celts and/or Druids in our past? More soon.