Of special note is a match to my aunt and uncle on the X chromosome. This is a 23 cM segment from either Eliakim or Susan- we cannot tell which one at this point. The X chromosome has a specific inheritance pattern. The chain is broken in any father to son descent. A father passes on his only X chromosome to a daughter- an exact copy. A mother has two X chromosomes that are recombined, likely into two or three segments, and passed on to her children. Thus, large segments on the X chromosome may travel intact for many more generations than autosomal segments (the other 22 chromosomes).
By identifying the ancestors responsible for an area of a chromosome, we can specifically use that one branch as we look at the other DNA cousins who match on this same segment.
The path of inheritance for this segment of the X chromosome for my aunt and uncle was:
1. Eliakim Marsh or Susan Long
2. Susan Marsh
3. Minnie Bishop
4. Eugene Cook
5. Beulah Cook
6. Jody's aunt and uncle
How did we figure out the relationship and the most recent common ancestors? Geography. We looked in our family trees and identified people living in the same area of the world at the same time. New Jersey, United States, 1800s. Then we compared surnames. In reviewing my notes on Marsh and Long, I realized that we had first corresponded years ago on these same people, where the relation had already been figured out. Here we are, connecting again, because we share identical DNA from our common ancestors born 200 years ago.