conuly

Okay. So, let's say you're looking at your average pea plant. And, following the rules of genetics as set out by Mendel, we know that if it's got one recessive gene for a trait, and one dominant gene for that same trait, the dominant one is the one we'll see.

Now, I'll interrupt a second and say that bio was never my subject. Chem was easy, and physics was a blast, but I only got through bio (the third time. Time one was a flop, and time two... well, I passed the tests, but I still wasn't able to really do the work) by memorizing a bunch of facts that didn't make much sense to me. (They made more sense once I took chem, and more again when I took physics. We teach high school science backwards.) So you'll correct me if I say anything devastatingly wrong.

Now, as I understand it, your chromosomes themselves just consist of a small number of nucleotides. So what makes a specific combination of nucleotides say "make this pea green" or "this one's gonna be a yellow pea" or even (in the case of extreme manipulation or random mutation) "purple all the way"?

For that matter, how does a pretty small difference in DNA make me a human, and outside we've got daisies? Or even a huge difference, every little detail different, how does it work to make things? How does it make sense?

I never understood that point. I just threw it back up on the tests, whatever I needed to know (the second and third years. The first year was a loss completely), and I've forgotten a lot of it, since I didn't really learn it properly the first (three) time(s) around.