3rd chimp

The DNA evidence of similarity between humans and chimpanzees does not tell us what we need to know. Recall that only four nucleotides (A, C, G, T) write the entire genetic code, so a purely random assortment would report us as sharing 25 percent of our DNA with any known life form, whether or not it has a brain. Also, as evolutionary anthropologist Jonathan Marks reminds us, we share 40 percent of our DNA with fish, but no one suggests that fish are 40 percent of a human48—or for that matter that humans are 250 percent of a fish. Crude concepts like DNA sharing do not really provide much help in understanding the human mind because it is the differences we need to know about, not the similarities. In any event, current estimates of how much DNA humans and chimpanzees share range from 95 to over 99 percent, depending on the rules chosen by the researcher making the estimate. 49 So it is not even clear yet how much DNA we do sha