I was recently asked to respond to an apologist page that challenged the scientific claim that human and chimpanzee DNA are very similar, which is evidence that we are descended from a recent common ancestor. You have probably heard the claim that human and chimp DNA are 96% the same. The apologist was referencing the work of Jeffrey Tomkins in his “peer reviewed” study showing that there is only 70 percent similarity. In fact, the the DNA of chimps and humans are so different, Tomkins claims, that there would not have been enough time for evolution to account for all the changes.
This is what I like to call, “sophisticated nonsense.” The very purpose of pseudoscience such as this is to confuse the public with complicated arguments that only scientists are likely to understand. We can turn such pseudoscience, however, into teachable moments.
So how does Tomkins come up with 70 percent. Well, he is not comparing point mutations of aligned segments. He is comparing chromosomes to see how many segments line up to some arbitrary amount. As many others have already pointed out, this result is not wrong, it’s just irrelevant. Well, it might also be wrong. Others have found it difficult to reproduce his results. But even if his analysis is accurate, it is simply the wrong analysis to apply to dating the last common ancestor.
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