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June 30, 2009

Are we 98% chimpanzee? Does it Matter?

Taylor is particularly scathing on the subject of primate rights. "I don't understand why conservation of the great apes has become synonymous with human rights and their similarity to us, whereas conservation of wetlands or a million other species doesn't carry any such conflations," he says. In this he echoes the Telegraph columnist Steve Jones, who has argued that it is a mistake to apply a human concept, such as rights, to an animal: "Chimpanzees share about 98 per cent of our DNA, but bananas share about 50 per cent, and we are not 98 per cent chimp or 50 per cent banana. We are entirely human and unique." ... Over the past five years, he points out, our understanding of genetics has become much more sophisticated. While there might only be a 1.6 per cent difference in the genome itself, the way it shapes our minds and bodies is radically different. "The key thing for me," says Taylor, "is that when you compare chimps and great apes with humans you notice how much more gene expression there is in humans."

Gene expression is when certain genes damp down or speed up chemical processes. A team from the Max Planck Institute for Evolutionary Anthropology showed that in human brains, there is a five-fold increase in the rate of gene expression. Other research has shown that more than 90 per cent of the genes in human brains have been "up-regulated" – that is, they have higher levels of gene expression. Most of these genes are associated with the speed of transmission of nerve impulses or energy production to fuel the brain. As Taylor says, "Bigger, faster, greedier, longer-living – that's the evolutionary story of the human brain."

Another genetic difference between us and chimps is "copy number variation". This is where a gene becomes copied, inserted into another part of the genome and yet still works. For instance, GLUD2 is a gene that governs an enzyme involved in nerve signalling in the brain. It is common to all the great apes, including humans – but with us, the gene has been copied, which makes the enzyme work faster. The resulting neurological intensity, says Taylor, "is like swapping a Lee-Enfield rifle for a machine gun".

Along with other genetic innovations, such as inversions, where whole chromosomes are flipped over, and gene splicing (in which one gene controls up to 50 proteins), the gulf between human and chimpanzee brains starts to widen dramatically. "If you add all this up," says Taylor, "the genetic similarity between humans and chimps drops to 87 per cent."

We don't need them to be our equals to decide that they are worthy of treatment better than mere things. That's sufficient but hardly necessary.

I've often wondered how we would persuade a vastly more powerful, long lived, and intelligent species to value our lives above those of farm animals. I'd like to think that creatures meeting a minimum standard of brain power and emotional complexity would earn the limited respect of a more powerful race. That's the frame of mind that gives me special respect for the dignity, happiness, and suffering of animals like wolves (and dogs), horses, elephants, whales, dolphins, and the great apes. Which reminds me of two science fiction stories. In The Uplift Saga there are special punishments for killing members of those sorts of animals, proto-sentient races that are capable (with genetic tinkering) of making it to full sentience. In Accelerando a character makes the case that how we treat emerging artificial intelligences will become important because it will dictate how they will treat us when they inevitably eclipse us in power and intellect.

Posted by OneEyedMan at June 30, 2009 4:43 PM

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