I got several wonderful responses to the question, two posts down, about why the chimp genome is 11.5% “higher” than ours, and whether evolution has done anything to enhance human well-being. Yesterday I heard from a prominent Philadelphia area developmental biologist who was reluctant to let me use his name because, as he puts it, “too many people are e-mailing their ministers’ remarks and praying for my soul.”
His answer was downright inspirational:
“1. Size doesn't matter much. The potato has 48 chromosomes, we have 46. Salamanders have enormous genomes, far bigger than ours, as do lungfish. There's a lot of gene duplication and non-coding DNA.”
“2. The evolutionary biologists do not use DNA as genetic determinists. Rather, they can look at common descent by seeing which non-coding DNA sequences are held in common. For instance, if cows and deer share sequences 10, 12, 8, and 11 (but not sequences 4, 5, and 6; and whales and hippos share sequences 10, 12, 4, 5, and 6 (but not 8 and 11), then it is very reasonable to assume that whales and hippos came from a common ancestor (that had 4,5,and 6), cows and sheep came from a common ancestor that had 8 and 11, and that all four groups had a common ancestor who had sequences 10 and 12...."