i dont know the full details but generally more dna means better status and more fruits it can eat. everything is found in the wild, just have to get lucky with the spawns in the grass, although maybe some grass patches spawn certain things more than others in the same area. there's also no real goal yet besides the missions. and the only thing thats breeding locked at the moment is boss dna, which you get the first monster with boss dna during the first mission. just like have fun i guess.