Actually, the Genovese Family was founded by Joe Masseria. After Morellos´s conviction in 1910, his group splinted off in several directions. Some of them seems to have ended up with the Reina Family, others travelled back to Sicily or to other parts of the US. A few of them, and that includes Pepe Morello and Ciro Terranova, joined the Masseria gruop who later became strong thanks to Masseria´s willingness to enlist criminal elements from the Neopolitan community.

In 1968/1969, when Puzo wrote the book, the common knowledge of the Mafia was poor. I agree with SonnyBlack that Puzo included tidbits of real Mafia incidents and real Mafia personalities in his book. But to say that his work of art is solely based on one Family, or one character, is a misconception.