I've been reading a bit about "junk DNA" and how much of our genome consists of this "non coding DNA" in comparison to "coding DNA".
I'm just an interested layperson but I thought all combinations of three base pairs encoded one amino acid, with some amino acids being encoded by more than one combination of base pairs.
But if that were true then all of our DNA would encode something.
Or if only a tiny percentage of our DNA is "coding" that would mean that the vast majority of possible combinations of three base pairs don't represent any amino acid.
Or it could mean that there are a small number of "meaningless" combinations of three base pairs, but that those combinations are vastly overrepresented in our genome.
Which is correct? What am I missing?