I realize of course that all humans are almost genetically identical; I’m thinking specifically about a rather unusual case, and how many genes these two close relatives would share. I’m just afraid my math isn’t capable of handling this.
Okay, so we have PN, who is the son of GF and LS.
We also have KN, who is the son of KS and SB.
Now, KS is also the father of GF by a woman other than SB. Therefore GF and KN are half-siblings, and KN is PN’s half-uncle.
But here’s where it gets tricky. SB and LS are half-sisters. Therefore their sons, KN and PN respectively, are half-cousins as well as half-uncle and half-nephew. From my own calculations I’ve determined that both GF and LS share 25% of their genes with KN. So would PN keep his parent’s ratio in regard to KN?
This is just to satisfy my intellectual curiosity; obviously, since KN and PN are both male it’s not like they’re going to marry and produce unusually inbred offspring or anything.