How are new genes made?

Question

Genes have "start" and "stop" commands, so how do new genes develope? What I mean to say is, does the code for start and stop mutate randomly, or does a new gene develope and then start and stop are put around it?

Answer 1

The most common way for new genes to happen is by duplication and modification of an old gene. It's far easier to make another copy of a gene by recombination then allow it to mutate to a new function (after all you still have the original) than it is to try to evolve a new gene from scratch.