Anyone who has kids knows personality is inherited largely
Anybody who has a whole buncha kids knows that the same set of genes from the same two parents can produce kids with wildly different personalities.
Any parents with "identical" twins knows they can have different personalities.
There are a few herds of genetically identical cloned cows, the cows in these herds exhibit the same ranges of temperament that would be found in a herd of cows made the old fashioned way.