Brazilain Jiu-Jitsu and Wrestling, is it necesarry to train in both?

I want to be an all-around fighter.Right now i concentrate on the striking aspect and planning how i would go through grappling(ground).Though of course it would be better if one will be able to train in both, do you think it is necesarry? What are the differences between the two discipline? Which one should i pick, or at least have to go through first?