In reality, you can mix any two species dna, but they will die or be sterile. Maybe you should have a similiar thing in darwinbots where you just randomly mix basepairs and if they are to different, the offspring will die. Notice I said basepairs, not genes. If you mix genes you could still get a working bot, but you also have love bots and how do you mix to different genes that are similiar without throwing away a gene.
Anyways, ask any creationist and they will define macro-evolution as an increase in "information".