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For the Corson Cousins newsletter, July 2012

Corson Surname DNA Project

The project currently has 61 participants, 58 of whom have results. The most recent results arrived for Divisions II and III, and results are pending for Divisions I and X.

Recent Results

Division II descendants…Racer!

Participants #58 and #60, with the surname Racer, document descent from Division II's Teunis Decoursey/Corsa (c.1702-aft.1763) and his son Benjamin Corsa/Decoursey/Racer. The two men are second cousins once removed. Their genetic signatures matched the Division II signature on 34 of 37 markers, and they both shared the same 3 mutations from the Division signature, which indicates that those mutations ware carried by their most their most recent common male-line ancestor, Thomas A. Racer (1848-1914).

In addition, the 3 mutations occur as duplicated values on markers DYS459, DYS464, and DYS724. This is called "Recombinational Loss of Heterozygosity" (RecLOH) and represents only one mutation event instead of 3. This means that their match with Division II is even closer, the equivalent of 36 out of 37 markers.

Interpretation of matches between people of different surnames requires more caution than those between people with the same surname, but given the 36-marker-equivalent match and their documented male-line lineages, the DNA results, while they cannot prove descent from Division II, certainly are consistent with it, and do not disprove it, as has occurred for other men with the Racer or Reaser surname.

Division-III Corson

Participants #34 and #49 upgraded their results to 67 STR markers. Their results identified two mutations (DYS444 and DYS576) that may be common to each of their Corson family lines, respectively. These tests will help us to identify other near-matching individuals and increase the precision with which we can estimate these individuals’ relationship to them (i.e., the number of generations back to a common ancestor).

Pending Results

Division I

Participant #1 (me) will upgrade his results from 67 to 111 markers, and Participant #22 will upgrade his results from 43 to 67 markers. Their most recent common ancestor is Zebulon Corson (1712-1786).

Division X

Participant #61, with the surname Corson, traces his descent from John Coursen (ca. 1810-aft. 1880) of Northfield, Richmond Co., New York. He would like to know from which Division he descends, perhaps most likely Division II or III.

Participants from Divisions IV and VII have been tested on no more than 43 markers. It would be useful to test at least one participant from each Division on 111 markers to be able to compare their results to other Divisions in the densely-populated genetic group R1b (Divisions I and III-Vroom).

Between issues of Corson Cousins, information about the DNA project is available at the project website (