A Close Look at the Chr#14 Segment Matching

Though we hoped to find one common ancestor that tied both Proctor and Sawyer/Minott trees together, that search came close but did not succeed. 

Not finding connections can be because they are behind dead-ends in research or because the research was flawed. Or it could be because there really are no connections. We are always working on the trees and scrutinizing the work we've done. But is there another possibility? This occurred to me as I was contemplating the detail of the segments these matches share with my father (CWJ).

Below is a graphic display of the available segments on GedMatch and, below that, are two table showing triangulations, first my father with LS (the lone Sawyer/Minott tree representative) and four Proctor tree representatives. There were two other Sawyer/Minott tree  representatives on MyHeritage that show segments like the one show here (so don't worry about sample size).

The start/stop locations of segments matching my father show a consistent difference between matches from the Proctor group and the Sawyer/Minott group. The Proctor group show longer segments, the difference denoted by the label "Set #2" in the graphics. What this could mean is that there are different ancestors represented between the two groups and that the Proctor group entails both, while the Sawyer/Minot group only has the "Set #1" ancestor(s). So, it seems to me that, when we get farther along, the answers we come up with should be consistent with this hypothesis. 

I call it a hypothesis simply because I am not an expert on meiosis and what the possibilities here are. It makes sense to me, but this is an area where I would like to get feedback from readers.

Meiosis is the process where two sets of entwined DNA strands come apart into four strands and then recombine into one entwined pair. In this process segments get broken up and recombined and this is when some of them end up getting lost or shortened. About 50% of the new cell DNA is from the mother and 50% from the father, with about 25% from each grandparent. There is more I'd like to learn about the details of this process. It seems to me that must be a fairly orderly breakup and recombination (not broken segments scattered everywhere). I also wonder how many breaks typically occur (which has implications, of course, for the probability that any particular segment is going to get shortened).  Again, reader feedback is very welcome, especially if it comes from biology majors well-trained on the topic.  

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