Isn't it that spiral thing with two strings of beads? The strings are chromosomes? I think the beads were labeled with A, G, P, or T, right? Well you said no cheating so I try to remember what the letters stand for. A for adenin, G for guanin, P for petamin, and T for tiamin? I'm 100% sure the spellings are wrong but that's how [I think] I remember pronouncing them. I'm just guessing, OK?! Please don't mock me!
Also I remember chromosomes of type X and Y that somehow determine your gender?
[I'm gonna watch a YouTube video about DNA! I just realized I don't know anything about it.]