I don't know how they "do" it, or if they exist before...there are red apples, and yellow apples. But imagine the yellow was first, how did the red come ?? Was it in the lab, or maybe somebody put a red tent map above the trees, for generation and generations...and that the red apples stayed red even if the red tent above was away...(evolution ?) ?? I don't know...It cannot work like that I suppose... But then, if you get red apples, by a "natural" way...how can we dinstinghuish, if the DNA code changes, if the apple was modified at the lab, or with the other way under the map...because with the tent map, you do not touch the apple..