RACHEL EGAN’S DNA LINKED TO PROSPER THOMSON – Part 2
‘More recently, links were also found to the grandparents of the man that Jo Thomson eventually married.’ New York Times 22 May 2021.
Thanks to Byron Deveson for the following …
The grandparents of Prosper were: Hugh Thomson 1839-1906 and Ann May nee MacTaggart 1846 – (?) on Prosper’s paternal side, and Benjamin Hawkes 1851-1934 and Alice nee Fortune 1850-1895 on his mother’s side. So, the connection could be through any one of these four.
The bottom line is that the DNA connection doesn’t necessarily come from the Thomson line. I note that the other three other possible perps have robust family trees and the DNA connection could come from Roma’s side.
If we were given the percentage (measured in centi Morgans) of the amount of shared DNA then it would be a straightforward exercise to work out where the connection is likely to be. The genealogical DNA databases would show up tens of thousands of DNA connections for anyone of mostly British descent and in many cases each connection will also be shared with others.
In my case I have 40,000+ DNA connections and of these 900+ are multiple shared connections. This means that there is enormous redundancy in the data, and hence there is enormous error checking capability. Of my 40,000+ DNA matches perhaps only 10% have attached family trees. The redundancy produced by multiple matches allows errors in these family trees to be detected and usually corrected. In other words, the DNA will steamroller over the previously dreaded “non-paternal” events and identify the source of DNA.
I have previously noted that in Australia the Federal Government currently has DNA data for at least 100,000 citizens plus all of the people from which DNA samples were obtained for other reasons (criminal cases etc.) and this is more than enough to identity the source of any DNA sample of European provenance. DNA originating from the second and third world is an exception at present because of the relatively low numbers of people from these areas who have had their DNA analysed.
China is likely to be an exception and I would expect that the Chinese Government is well on the way to tagging their entire population (well, the people who don’t have sufficient power that is). Incidentally, it has become apparent that China has been acquiring DNA from sources outside China, and outside Chinese ethnicity. And that begs the question of what they are up to.
Byron Deveson
The Somerton Man 
Identifying my birth parents from my DNA sample taken in 2018 was an evening project for three months. And that was four years ago now. Very fortunately, I connected with a first cousin once removed. What’s more is he was familiar with the family politics, and armed with that information my placement in the tree came swiftly, even though my father was one of nine and mother one of four siblings. Also helpful were online obituaries – basically family trees in a gift basket.
Point is, it really should be possible for Rachel Egan to reconstruct her grand-paternal family tree in this day and age, just by web sleuthing, and from there identify a missing relative. Also, there should be someone still living with memories of the Somerton Man, but we do not have long. Evoking my personal experience once again, I was able to connect recently with the 95 year old sister of my great-grandmother on whom I had the least information. She was a total cipher and there is no web information about her at all. My guess is the Somerton Man was estranged from his family as well and left few to no public records. So time is of the essence here…
I am under no illusion that this is something you do not already know. Just sharing my own personal experience with this line of work.
Matthew K.
Thanks Matthew, much appreciated.