yup...personality is more of "programming" so evironment plays a bigger role...but the ability (learning, agility etc) of the individual to be "easily programmed" is genetic.

each cell have DNA so if you are to modify an individual, you'll have to do it before they replicate (sperm and egg cell pa lang) habang unicellular pa yun...so pagnagreplicate...all the succeding DNA's will carry the same component (the modified DNA).