The expected amount for a 2nd cousin is 3.125% which is 212.50 c M, right in the middle between these two.
Checking my brother, I see the same effect – he has 282 c M with John versus 185 with Dick.
Not surprisingly, when I look at Dad I find that he shares almost twice as much with John as with Dick.
So I decided to collect some detailed statistics on those specific relationships with a google form (click here) that includes total segments and segment sizes for a future blog post First round results are written up at https://blog.kittycooper.com/2017/09/the-25-relationship-a-first-look-at-the-data/ ] The companies predict reasonably well for close family but it is just not possible to be accurate beyond that due to the randomness of DNA inheritance.
However, knowing that I had just had a second baby, Jessica recommended I bring him in to have His latch evaluated.
Turns out, my second baby had a tongue and lip tie!!
Many people have the illusion that if their testing company says a person is a 3rd to 5th cousin they really will be. The testing companies are just making the best guess they can from the data they have.
They do not seem to take segment sizes into account, rather they primarily use total shared DNA measured in centimorgans (c Ms) for their relatedness estimates, usually the sum of all matching segments of 5 c M or larger.
I initially began working with for orofacial myofunctional therapy to correct my misaligned bite.