Tuesday, August 12, 2008

Humans Are Not 98% Genetically Identical to Chimpanzees

I have been researching the purported genetic near-identity between humans and chimps-- asserted as the "scientific" basis for the Great Ape Project--and found (unsurprisingly) that the entire advocacy line that "humans and chimps share 98% of our genes" is plain false. This gets a little complicated, so stick with me.

First, the 98% figure is probably overstated. An article in Science puts the actual figure at 94%. (Jon Cohen, "Relative Differences: The Myth of 1%, June 29, 2007). But even these figures are only measuring about 2% of our total genetic makeup--that is, those genes that code for proteins, the building blocks of our physical bodies and functions.

The vast majority of our DNA, known as "non-coding DNA"--sometimes called "junk DNA" because it was once thought not to have function--is very different in humans from most non coding genes found in chimps and other apes. Moreover, recent research has found that contrary to previous belief, this repetitive DNA isn't "junk" after all, but has distinct purposes. Research continues as to the exact nature and functions of non coding genes, but given the wide differences between human and ape non coding DNA--even if the purported 98% genetic similarity to coding DNA is true, it is actually only 98% of a much smaller percentage of our total genetic makeup, perhaps as low as 98% of 2%!

Proponents of the Great Ape Project might reply in defense that the coding genes are the ones that really count, but that is not scientifically supported anymore. And even if true, as we have discussed previously here at SHS, the 2-6% difference constitutes tens of millions of biological differences.

So this is the bottom line: Creating a human/chimp moral equivalency is not scientifically justified based on a close biological relationship between us that is actually quite vast. Rather, as one scientist quoted in the Science article referenced above put it about this issue:

I don't think there is any way to calculate a number [percentage of similarity]. In the end, it's a political and social and cultural thing about how we see our differences.
Exactly: This is about politics and ideology, pure and simple.

I'll write more fully on this matter when I have a little more time because I think it is important to knock down the fiction that humans and chimps are nearly identical genetically. But know this: We are not 98% (or 94%) chimp and they are not 98% (or 94%) human. And that's the scientific truth.

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6 Comments:

At August 12, 2008 , Blogger John Howard said...

Surely all that matters is that apes aren't born to humans, and humans aren't born to apes.

Isn't it a perfectly good way to explain what makes us different? Only humans have human parents, only humans have human children.

Trying to find some other criterion for what constitutes a human worries me, because it would only seem to matter if people tried to create humans some other way than being the child of a man and a woman. Are you trying to prepare us for that or something? Why not just prohibit creating people any other way, then we won't have to come up with some other criterion for what is a human and what isn't.

 
At August 12, 2008 , Blogger Wesley J. Smith said...

That was always a way of distinguishing different species. But the reductionists of modern science/ideological advocacy wish to engage in radical reductionism to create a moral equivalency between us and them. It is thus important to contest their facts when they prove to be wrong.

Thanks for your long-time loyalty to SHS, John. I appreciate it.

 
At August 12, 2008 , Blogger John Howard said...

Also, shouldn't we expect the DNA to be nearly identical? There are eyes, lungs, hearts, blood, stomachs, hair, hands and feet, teeth, wombs and testicles, etc. There isn't one organ or biological function that isn't in both, we're 100% identical, just different because animals are like their parents.

 
At August 13, 2008 , Blogger Donnie Mac Leod said...

In support of your observations Wesley, it is apparent that humans are a family that have emotions & life skills that no other animal has. We are also prone to moralistic choices which other animals are devoid of. I am not in the least surprised to see the true percentages do not equate to the 98% claimed by folks trying to claim moral values on animals that have no reciprocating moral values towards us.

 
At August 13, 2008 , Blogger Laura(southernxyl) said...

I second John's argument and will further point out that we share many attributes with plants. How else could we receive nutritional benefit from eating vegetables? And so what?

 
At September 04, 2008 , Blogger Joel Radford said...

Good to know. But what about mice? The Sydney Morning herald today says "More than 90 per cent of the mouse genome can be lined up with a region on the human genome"
http://www.smh.com.au/text/articles/2008/09/03/1220121331208.html

 

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