You could be a mesomorph, which means you are thicker and wider and your body is naturally more capable of supporting more muscle. That is most likely what you mean by genetics. Not the prick who goes "your black". There has been no empirical evidence to prove it, and there have been numerous studies testing that theory, buddy. It is a myth proven false, so go beat your dead horse you racist.
Anyways, try to do more than just those basics. try to do a hanging row by propping your feet up on a chair so you are parallel to the floor, arms stright out in front of you, and performing the row from there. Do differing hand positions on pullups (chinups, curlups, neutral grip if your bar has it) and also try to throw in leg stuff you don't need weights for like body squats, lunges and wall sits. Won't be long and you will be a man-monster!