Many people believe that there is compelling evidence Jestyn's son, Robin Thomson, is the biological son of the Somerton Man. This is based on shared genetic characteristics such as the shape of their ears, hypodontia, and their high calf muscles.
Shown here, one of Robin's ears, one of the Somerton Man's, and a 'normal' ear with the Cymba, Cavum, and Crus Helicis labelled.The hollow of the ear is called the "concha." The concha has a ridge that runs along it called the Crus Helicis. This ridge divides the concha into two halves. The top hollow above the ridge is called the "cymba" and the bottom hollow is the "cavum," as indicated by arrows. In "normal" ears, the cymba is smaller than the cavum
The middle photo is the Somerton man's ear. Notice his ear is inverted. The ridge is much lower down, and it is his cavum that is smaller than his cymba. So it is reversed, compared to a normal ear. Less than 1% of the population have this feature. On the far left, is a photo of the ear of Jestyn's son "R" who was born in 1947 (a year before the Somerton man died).
Robin had a sufficiently high-profile job that his photo appears in many newspapers. So it was a matter of trawling through back issues of papers to find a good shot of his ear, and hoping the newspaper kept the high resolution original. In 2010, Derek Abbott and his team struck lucky and and found an earshot with sufficient resolution that they could compare it to the Somertonman's (see above).
That like the Somerton man, his Crus Helicis ridge is further down, making his cymba bigger than his cavum. So what does this all mean? Well there is a less than a 1% chance of having this rare ear feature. So the probability of picking two unconnected people at random from a population both possessing this ear feature will be quite small. This is called the "null hypothesis" that they are unconnected. So given that the null hypothesis has a low probability, it would lead us to suspect there may well be a connection between Robin and the Somerton man, and that the chances of it being a random coincidence are relatively small.
Notice three other genetic similarities in the ear's of the Somerton man and Jestyn's son, they both have attached rather than hanging earlobes, they both have slight peaks on the outer ridge (helix) of the upper ear, and they both have an unpronounced tragus and antitragus.
Whilst each individual feature alone could be written off as random chance all of these in combination makes for compelling evidence.
My understanding of genetics is fairly basic, and goes no further than Mendel and his peas. Personally I don't see it, but am willing to bow to the expertise of those who do. I would question which of these traits are dominant, a child is after all the product of two people, and which are recessive. How much do we know of Jestyn's side of the family?
That 'Certain Adelaide University Personality' Derek Abbott has floated the idea that the Somerton Man was in fact related to American President Thomas Jefferson. This seems pretty far fetched to me. Thomas Jefferson's family tree is well documented and if there were any missing relatives I'm sure we would all know about it.
Geneticists tell us that every single person on earth is at the very most, 50th Cousins with every other person on the earth. Well we have to be. If there are 7 billion people on the planet, every person has 2 biological parents, 4 biological grandparents, 8 biological great-grandparents and so on... it doubles with every generation. Well, if you follow your family tree back to the time of the Romans, 64 generations ago, that tree would need 1,000,000,000,000,000,000 individuals! This is a number larger than the number of humans that have ever existed. As Bill Bryson once said, "You couldn't be here without a little incest - actually quite a lot of incest", it is there for quite possible (in fact probable) that the Somerton man was in some way related to Thomas Jefferson. If you are in a relationship with someone from your own countryand who is of the same ethnicity there is a 1 in 5 chance you share a common ancestor less than 10 generations ago.