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From the Corson Cousins newsletter, July 2005
Corson Surname DNA Project
The Corson DNA project now has 15 participants, 14 of
whom have received their DNA results. Since
my report in the last issue, the project has made two significant finds: we now
know the “ancestral” Y-chromosome genetic signature for Division I (New
England branch) and that for Division II (Sussex Co., NJ branch).
Knowing a Division’s ancestral genetic signature
makes several things possible. With
it, we can determine (1) how closely one Division is related to another and (2)
whether a family with a brick-walled male-line ancestor descends from a known
Division or not. In addition, as
DNA tests increase in resolution and more people are tested, knowing a
Division’s ancestral genetic signature eventually can indicate where the
male-line ancestors of the Division’s progenitor originated.
Determining the Y-DNA
genetic signature for a given male ancestor requires testing male-line descendants
of at least two different sons of the ancestor. If the results of the two descendants match, then their
common male ancestor almost certainly had the same genetic signature.
In the rest of this article, I will describe how we determined the
“ancestral” genetic signatures for Divisions I and II, then explain what the
results currently tell us.
Three project participants (including me) come from Division I, whose progenitor was Cornelius Cursonwhit. Since Cornelius had only one known son we cannot determine Cornelius’ genetic signature. Instead, we can go back only to his son, Samuel Corson, who had four sons. Two descendants of Samuel’s son Zebulon Corson had genetic signatures that matched exactly, while a descendant of Hatevil Corson/Colson matched the other two Division I descendants on 40 of 41 markers (Fig. 1).
Two participants come from Division II, whose
progenitor was Jan Corszen. A
participant with the Corsa surname, who traced his ancestry to Jan Corszen
through Jan’s son Benjamin Fletcher Corsse, had the same genetic signature as
a Corson participant who traced his ancestry to Jan through Jan’s son Jacobus
These ancestral genetic signatures indicate that
Division I descendants belong to a broad genetic group (“haplogroup”)
currently called “R1b”, while Division II descendants belong to an entirely different genetic group, currently called
“I1a”. Researchers estimate that the most recent common
male-line ancestor of these two haplogroups lived about 40,000 years ago.
In other words, Cornelius Cursonwhit and Jan Corszen did not have any male-line
ancestors in common for thousands of years.
Thus, Division I and Division II descendants are genealogically unrelated
in the direct male line.
Their very different
haplogroups, however, do not tell us whether they came from different countries
or not. Currently, the birthplaces
of both men remain unknown. Sparse
documentation leans toward a Dutch origin for Cornelius Cursonwhit, while debate
about a Dutch or French origin for Jan Corszen continues.
Haplogroups R1b and I1a occur throughout Europe, but with varying
frequency depending upon region. Because
the haplogroups have such broad distributions, it may be more useful to look at
specific marker values in the genetic signatures themselves.
For example, Division I has values of 25 and 10 for markers DYS390 and
DYS391, respectively; in haplogroup R1b, this combination appears to occur more
frequently in populations from northern Germany, the Netherlands, and Denmark
than in populations from, for example, Ireland. Similarly, Division II has values of 14, 22, and 13/14 for
markers DYS 19, DYS 390, and DYS 385a/b, respectively; in haplogroup I1a, this
combination appears to occur more frequently in Germany and Denmark than in
Norway and Sweden. Still, these
statistical probabilities for just a few markers do not provide conclusive
evidence. As public DNA databases
continue to add more international results, we hope to find patterns among more
markers that can help us determine from what regions family progenitors may have
come. For Divisions with European
origins, luckiest of all would be to find a close match with a European
individual, a descendant of a Division relative who remained in Europe.
Though we have determined these ancestral genetic
signatures, we still encourage male-line descendants from Divisions I or II to
join the project. Additional
participants will allow us to look for marker values that may indicate
particular family lines within Divisions. For
example, male-line descendants in Division I-A (surname “Corson”) have a
value of 13 at marker GATA-A10, while a descendant from Division I-B (surname
“Colson”) has a value of 12 (Fig. 1). If
another Division I-B descendant has a value of 12 at GATA-A10, we will have a
marker value that can tell us the difference between Division I-A and I-B
descendants (though it is more useful for descendants who have the same
One last finding: at the end of June, I received
results from a different kind of DNA test, called an SNP (single nucleotide
polymorphism) test. It revealed
that I (and the rest of Division I) belong to a subgroup of haplogroup R1b
currently called “R1b1c”. It
doesn’t tell us much more about Division I right now, but current SNP research
is looking into the geographic distribution and past migrations of these
We are still looking for additional participants from
the other Divisions to help us determine their ancestral genetic signatures.
One more participant may be all we need to do so for Divisions III, IV,
or VII. For those of you unsure of which Division you may belong to,
a DNA test of a male-line descendant in your family may provide the answer.
The CCFHA has one remaining $40 reimbursement of the test cost available.
You can read more about the project, see lineages of current
participants, and see test results and interpretation at the project website:
contact me if you have any questions about this project or if you, or someone
you know, might be interested in participating.
(P.S. If you find any errors in the above figures, please let me know so I can correct my database.)