If the chimpanzee genome is 98.6% human, does that mean that chimps deserve 98.6% of human rights?
If chimpanzees share 98.6% of the human genome (all of the biological information needed to build and maintain an organism) wouldn’t that make them 98.6% human? Shouldn’t they be accorded 98.6% human dignity? Not a Chimp: The Hunt to Find the Genes that Make Us Human by Jeremy Taylor begs to differ. He says that leading primatologists like Frans de Waal and Jane Goodall are pulling the banana skins over our eyes. Indeed, bananas share 50% of the same DNA as ourselves but that does not mean that we are all half bananas.
Many a scientist is concerned with the loss of wilderness space for the great apes. Nor are scientists immune to the very human propensity to anthropomorphise everything around us. These two forces lie outside the realm of science but they exercise a strong psychological grip on the practitioners of science. The upshot is an active promotion of ape rights by experts in the field. Whilst Jane Goodall may have failed to convince an Austrian court that a chimp like Matthew Pan could be a person, her advocacy has had more far reaching effect in Spain and New Zealand. Both countries have enacted legislation recognizing primate rights. What scientific evidence can a Jane Goodall, Frans de Waal or even a Peter Singer draw upon to build a case for simian rights? Nothing terribly compelling.
Although man branched off from a common ancestor some 6 million years ago, our need to compare living DNA with living DNA has led to in depth investigation of the chimpanzee in our search for human origins. Now, since we have discovered that we share 98.6% of the same genes, the evolutionary differences between humans and great apes can’t be all that great? Wrong. When we look at how the genes function and copy themselves the similarity drops to 94%. When we come to look at the immune system the similarity plummets to 87%.
Not a Chimp leads us into some of the latest discoveries in the Aladdin’s cave of the genome. Already we can see that there are big differences between human and ape and we can expect that further research will only widen that gap. Let’s have a look at some of them.
Among the "handful of genes" that make us human we find FOXP2: a master controller gene producing protein that turns other genes on or off in the area of language and speech articulation. FOXP2 is thought to play a significant role in bird song and bat echolocation. Between mice and apes there is one amino acid difference in this gene. Between apes and humans there are two amino acid differences. We can also detect significant differences in ASPM and Microcephalin, which govern brain development. There is a significant gap between primates and other animals. The gap is even bigger between primates and human beings. That’s not all, the structure of the "social brain" is another area of significant difference between humans and apes. We have more spindle cells (the neurological substrate of moral intuition) and (perhaps controversially) more mirror neurons with which to imitate and learn. Monkey see, monkey do? Chimpanzees learn to use twigs to fish for termites. Primary school teachers post videos of them doing so on the internet and teach children to speak up for animal rights.
Evolution is a work in progress. If anything, the human genome is changing at an ever greater rate. With the shift to agriculture and "self-domestication" 10,000 years ago a number of genetic changes have been naturally selected. ADHD (due to dopamine) seems to have spurred migration, vasopressin has increased bonding, serotonin fostered the ecstasy of dance. The trade-off in brain expansion, plasticity and creativity that these changes have wrought, however, has been Alzheimer’s, schizophrenia and bi-polar disorder.
So much for recent changes. Other evolutionary differences are much, much older. The deletion of the CMAH gene was a successful, if somewhat quick and dirty, evolutionary response to primitive malaria. Again there was a price to pay. Without NeuSGc we have been left at the mercy of auto-immune diseases like AIDS, hepatitis, type 1 diabetes and psoriasis. Of recent memory was that 2006 trial of TGN1412 that proved harmless to monkeys but threw human patients’ T-Cells into overdrive, swelling their heads and making them look like elephants.
So, by analogy, could we not at least run the Peter Singer argument that apes should get the same treatment as sub-normal humans? Taylor reckons this an insult to both species. The argument from analogy begins to break down when we examine even more distantly related animals like crows and dogs. Functional necessity can lead to evolutionary changes that do not rely on possession of the same genes. Dogs look into your eyes and can guess where you are pointing. Chimpanzees open their hands begging for food even if you have a bucket on your head and can’t see them. Crows can make hooked tools from ferns, use cars to crack nuts, and even re-hide food from birds that might have seen them when they were stashing away their grub in the first place. Crows can even use intermediate tools – poking out one stick to get to a longer stick to get to the food. Chimpanzees show no understanding of folk physics. In tests for intelligence the corvids prove monkeys to be less than bird brains. If apes are like Commodore 64s compared to the human Pentium, birds could be reckoned an Apple Mac.
Humans and chimpanzees may share similar genes but they are very different species. Our feathered friends do not share our genes but they come closest to expressing a theory of mind.
Dr Richard Umbers is a Catholic priest with a New Zealand accent. He lectures in philosophy in Sydney.