Doug,
Thank you for that wealth of information; I did indeed take it into consideration in 2006. Since my original post, test results from 2 additional Vrooms and 6 additional Corsons has followed the same pattern. Most recently, the DNA of a documented descendant of Christiaen Corssen (b.1676), a brother of Benjamin Corssen (b. 1686), matched that of the other Corssen descendants, allowing us to push the Corssen genetic signature back by one generation, to Cornelis Corssen (b. 1645), documented son of Cors Pieterszen (b. 1612).
In contrast, the Vroom genetic signature has been established only to Hendrick Vroom (b. 1683), documented grandson of Cors Pieterszen (see
http://www.corsondna.com/DivisionIII.gif for the Corssen-Vroom tree, also attached).
So, the goal remains to find a male-line descendant of one of Hendrick Vroom's 2 other sons to see if Hendrick's father (Hendrick Corssen Vroom) also carried the Vroom genetic signature.
Michael Corson