User blog comment:Master Sima Yi/Assassinews 03-03-'13 — Assassin's Creed IV: Black Flag trailer and screenshots/@comment-4999424-20130305125147/@comment-1153722-20130305232557

IlMualim, William being related to Edward or Connor doesn't mean he has the exact same genes as them. Nobody has the same genes as another person.

William doesn't have the right genes because even though he may have been related to Altaïr, Ezio, Edward, Haytham or Connor, his bloodline is likely mixed with so many humans with no First Civ genes in their blood that William's DNA has less concentrations of First Civ genes as well. Desmond is a conversion of both his father's and mother's genes, and those combined give Desmond a higher concentration of First Civ genes than they do separately.

(This sounds quite noobish.)