We have long believed that the majority of Casey men living in the South descend from early Casey ancestors that arrived in the early 1750s. Based on the 1960s manuscript by George and Abner Casey, these men were connected to early Casey men in Virginia. There are around 50 male Casey men in South Carolina by 1800 (mostly in Spartanburg County, SC and the rest in nearby counties). The ancestor of all of these men has been stated to be Abner Casey and his wife Harriet Green but no primary documentation has been found to date on this man or his wife.
Since I could not make any progress with all the source documents found in South Carolina over the last 40 years, I decided to become the admin of the Casey FTDNA project in hopes of breaking through this brick wall. Here is where we stand after ten years:
1) Around 25 Casey YDNA testers who have ties to early South Carolina (or believed they have ties to early South Carolina) have tested to be very closely related in the last 200 to 400 years. There is only one exception - Elisha Casey is related only around 1,400 years ago - too early to share a common Casey ancestor.
2) Anyone who tests positive for the YSNP branch, FGC5639 are all descendants of a common Casey male ancestor in the last 300 or 400 years as we expected. There are only two confirmed men with much older connections (500 to 700 years) that are connected to this surname cluster. Since there is little YSTR variation between these testers but a huge variation from haplogroup L226 YSTR signature, this line is very closely related in time frame of the colonization of early America.
3) For the two older lines, one very big surprise is a Kersey tester who has his line traced back to the early 1600s in Oxford, England (it is believed that this early Casey line moved from Ireland to England and changed their name to the English Kersey surname to hide his Irish heritage). During the last week, we discovered our first Casey line from Virginia and North Carolina in the 1700s. Both of these lines are FGC5647 positive and FGC5639 negative. Both of these lines probably much older than the colonization of America but have a common Irish Casey ancestor around 500 to 700 years ago.
4) The next closest YSTR matches are several "Carey" testers. These connections are a few hundred years earlier than the Kersey and the older Casey tester. It is believed that they share a common ancestor between 700 and 1,100 years ago. It is not certain if the share a common Casey or Carey ancestor - but similarity of surname is very interesting.
5) We are very lucky to have a major YSTR branch 460 (11>12) which pretty much divides all of these Casey lines into two branches. We believe that this branch happened around 1650 to 1750.
Unfortunately, we do not have any Casey men who reside in Ireland today that are related to this South Carolina cluster of testers. The entire Casey project only has five Casey men that are tested from current residents of Ireland. None have tested or are predicted to be related to this very large Casey genetic cluster in early South Carolina:
535407 is from County Sligo and has tested I-Y5451
5702 is from County Tipperary and has tested DC69 (branch under R-L226)
129039 is from County Cork - only tested for 12 markers
260341 from County Limerick - R-M269 (but not R-L226)
484828 is from County Cork - I-P37
6) Of the 83 known testers with the Casey surname, 30 % currently belong to the South Carolina cluster. It is believed that around 25 % of all Caseys in the world are related to this one genetic cluster that share a common Casey ancestor.
If you are Casey descendant of any Casey line that you believe has ties to early South Carolina (those that descend from the speculative Abner Casey and Harriet Green), it is highly recommend that you have your 67 markers tested at FTDNA and join the Casey FTDNA project.
If you are a Casey descendant that currently resides in Ireland and who can trace their Casey ancestry back to the following Irish counties: Clare, Tipperary, Cork, Kerry and Limerick (to at least a birth before 1870), I will sponsor your 37 marker test at FTDNA as long as you agree to continue us to allow testing your YDNA if turns out to be a significant discovery. For further information contact me:
http://www.rcasey.net/DNA/Casey/Contact.html