Are We 99% Chimps?
Not so Fast, Bonzo
Putting myths to rest is always a good thing, and right now it needs to be bedtime for Bonzo.
Journalists and science writers endlessly repeat the biological bromide that "humans and chimpanzees are 99% genetically identical," a factoid that has taken on a life of its own and, pun intended, has evolved into a worldview assumption. If our genes are virtually indistinguishable from those of chimpanzees, the reasoning goes, we must be virtually indistinguishable from chimpanzees!
Kevin Williamson, writing at the National Review of all places, made this leap about Ivanka Trump's rude welcome by fellow airline passengers recently. If we are, after all, 99% chimps, it's not surprising our inner apes would make an appearance, say, on a JetBlue flight.
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Now, people certainly are capable of acting like animals, and the scientific-sounding assertion that we really are animals at heart seems to explain it. But there's just one problem: It's not true. Our DNA is not 99% identical to that of chimpanzees. Even if it were, that wouldn't make us apes-except-for-one-percent. That's bad genetic science and reductionist philosophy, to boot.
Writing at Evolution News and Views, David Klinghoffer points out that the "99%" myth is based on hopelessly outdated research. But it got a shot in the arm after researchers at the Genome Consortium announced in 2005 they'd sequenced chimp DNA and compared it with our own.
Newspapers the world over trumpeted the similarity between the two genomes as further proof of our close ancestry. What they neglected to mention was that the project only compared protein-coding segments of the genome, which in humans, account for just 2% of the total! The rest is what Francis Collins once termed "junk DNA." Except, as scientists have since discovered and Collins has admitted, this "junk" serves regulatory roles that determine how other genes are expressed, particularly in the brain. In other words, "junk DNA," which makes up the vast majority of our genome, is a vital part of what makes humans, human and chimps, chimps.
Second, it turns out that the "99%" figure resulted from using a complete human genome as the template to sequence that of chimpanzees. That would be like assembling a jigsaw puzzle based on how another puzzle fit together!
The comparison also selected for areas of greater similarity and discarded those that didn't match. To put it very simply, the two genomes looked similar because researchers expected them to look similar.
Based on what we now know, biologist and Senior Fellow at the Center for Science and Culture, Ann Gauger, estimates that humans and chimps share around 92% of our DNA. To put that in perspective, scientists tell us that we're 90% identical to cats.
But then it gets more complicated. As Gauger admitted in an interview with the Discovery Institute, recent advances show how differently human and ape bodies put specific genes to work. Special proteins called transcription factors switch certain genes on and off during development, and roughly a third of these are human-specific. Apes don't even have them.
The differences on the level of gene transcription, splicing, and expression are so profound that Gauger compares the process with an operating system, and protein-specific DNA with lines of code. They may look the same, but the results — a human and a chimp — could hardly be more different.
As former British Prime Minister Benjamin Disraeli observed indignantly upon reading Darwin, human beings are more like angels than apes. And he was right. No animal speaks, composes symphonies, paints masterpieces, sends probes to Saturn, or more importantly — desires a relationship with God.
Even if the "99%" canard were true, it wouldn't make us 99% chimps any more than a diamond's carbon composition makes it 99% coal. We're not the sum of our genes, and it's past time that journalists and commentators evolve past this outdated assertion.
(Editor's Note: This article originally stated that the 2005 Nature study only compared 2% of the human genome to chimps. It actually compared the whole thing, but used selective methods that ignored major dissimilarities. We regret the mistake. See Dr. Ann Gauger's interview with 'ID:The Future' for more information on the dissimilarity of chimp and human DNA. (Series is here, here, here, and here.)
Originally posted at breakpoint.org
