As a way of demonstrating what we can do by testing the multitude of descendants
of the 1671 immigrant, Peter CARRICOE, I would like to suggest you view the
"node chart" I've constructed for my STRAUB project, which is further along
than
the CARRICO project.
http://dgmweb.net/genealogy/DNA/Straub/StraubDNA-NodeChart-I1a-AS5.shtml
In the first column of the table is the name of the progenitor, Johann Pieter
STRAUB I. In the next column, are his sons, in the next his grandsons, and so
on. Each row is a line that has been tested, and every subject has been tested
to 67 markers.
The white table cells indicate individuals who bear no mutational changes; and,
as shown, two lines descend from the progenitor with no mutations. The other
six lines bear one or two differences from the progenitor and from each other.
The question is, where on these lines of descent did these mutations occur?
As of now, we have only one case where the individual who bears the new mutation
is known. This is #23492, in the bright green table cell, with the mutation in
red text. He is a brother to #26156 (they happen to be my first cousins).
Their descendants will henceforth be separable based on this mutation. So,
where did the other mutations occur? We won't know until more individuals are
tested, but here is an example of a strategy to find out...
Let's say #32866 (the pale yellow table cell) wants to know where his single
mutation occurred. The ideal strategy would be to find someone who descends
from a brother of his 3rd-great-grandfather, Johann Heinrich. If that
individual does not bear his mutation, he knows the mutation happened in a later
generation. The next line to test would be someone who descends from a brother
of his 2nd-great-grandfather, Isaac. If that individual does not bear his
mutation, he knows the mutation happened in a later generation. The next line
to test would be someone who descends from a brother of his
1st-great-grandfather, and so on... At some point in this testing, there will
be an individual who shares the mutation, and at that point you'll know your
most recent common ancestor must have been the first one to bear the mutation.
So, how does this help with your genealogy?
For the sake of discussion, let's say the mutation shows up in a descendant of
Samuel Daniel's brother, Emory, but not in any descendant of any of Isaac's five
brothers. This has to mean that Isaac, alone (not his father or his brothers)
was the first bearer of the mutation, and that any of his descendants should
carry it. Anyone claiming a descent from Isaac who doesn't carry the mutation
needs to re-examine their paper genealogy.
And this is how it's done. You use the DNA test results to construct a
descending genetic "tree," where the mutations are the nodes indicating the
branching points. If your paper genealogy is correct, the mutations shown in
your test results have to be "in synch" with the node chart. Will there be
enough mutations to define every branch in every generation? Not at present,
not with just 67 markers, but as I indicate on the table, the two individuals
with zero mutations are currently testing additional markers, and we will keep
testing available markers until we can gain some separation of those two lines.
So... How useful are these test results genealogically? Extremely. The eight
individuals included on this table have haplotypes matching no one else, even at
just 25 markers, yet they match each other at 67 markers within only a one or
two mutation difference from the progenitor. And as more individuals are tested
at more markers, we can show ever more precisely how they are related.
We have an even better potential for the descendants of Peter CARRICOE because
most of his living descendants will be nine or ten generations distant from him,
while the above STRAUBs were only seven or eight generations from their
progenitor. In other words, more opportunity for mutations.
Hope this helps explain where I hope we're headed with the CARRICO project, at
least with regard to the U.S. descendants of the 1671 immigrant. And if my
other projects are any indications, we will also find CARRICO has more different
origins that we expect...
Diana