The Mismeasure of Man: Why Popular Ideas about Human-Chimp Comparisons Are Misleading or Wrong
By Ann Gauger
The more we learn about life,
the more clearly it reveals design.
You have probably heard that our DNA, the stuff that makes us human, is only 1% different from chimps. The claim that we are little more than apes is now part of the Zeitgeist of our culture, having been propagated in the popular press for nearly 40 years. However, that statement and the conclusions drawn from it are false.
Let’s look at the first claim, that we are only 1% different from chimps. That measurement only compares base changes in human and chimp DNA. It doesn’t include other kinds of changes to the DNA, like deletions and insertions or rearrangements. In addition, because of the sequencing methods used, repetitive DNA is not included.
Now that complete or nearly complete genome sequences for humans and chimps are available, a better picture of our differences and similarities is emerging. A 2007 essay in the journal Science, “Relative Differences: The Myth of 1%,” says this (the pdf is here ):
Researchers are finding that on top of the 1% distinction, chunks of missing DNA, extra genes, altered connections in gene networks, and the very structure of chromosomes confound any quantification of “humanness” versus “chimpness.”
To be specific, in addition to the 1% distinction already noted, entire genes are either duplicated or deleted between the two species, sometimes in long stretches called segmental duplications. Such duplications represent a 6.4% difference between chimps and humans. There are also insertions and deletions within genes, which affect the structure and function of the proteins they encode. That contributes another 3%, according to some estimates. And there are entirely new genes, specific to humans.