THE MRCA OF EDWARD AND PETER:These three paragraphs begin an analysis by Fred Coffey, the Coffey Cousins' DNA guru. Click on the title link to read the entire article.
We have been working with two major lines of Coffey/Coffee ancestors, and DNA tells us that they are clearly related. There is a MRCA (Most Recent Common Ancestor) back there somewhere. We are of course talking about the "Edward Group" and the "Peter Group".
Do we have information on when this MRCA might have lived? Yes we do, but our perception has changed as new information develops. I want to lead you through the following exercise, exploring the development of our understanding:
Consider two of the tested individuals: We have "Luther Coffey" who descends from Edward, and we have "Carol Coffee" who descends from Peter. Both of these individuals have 67-marker tests, and they differ from each other at only two markers – a "genetic distance" of two. There is no doubt that they are related.