Anti-humanists love to point to the seeming genetic closeness of the expressing genomes between us and chimpanzees. It is all a vain attempt to reduce us to their level–or sometimes, try to raise them to ours.
It’s all nonsense, of course. As I have written before, the seeming closeness masks the millions of biological differences contained in this seemingly small divergence.
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. There are also changes that affect the timing and amount of gene expression. These changes include the insertion of new regulatory sequences upstream of genes.
For example, some 6% of our genome is unique Alu insertions, as they are called. And Alu sequences are known to affect gene expression. In addition, there are human-specific increases in DNA methylation that affect gene expression in the brain, and increased RNA modifications in the brain. These changes would not be detected by simply comparing DNA sequences. Yet they affect gene expression and interaction. Indeed, by one measure, 17.4% of gene regulatory networks in the brain are unique to humans.
Then there are DNA rearrangements. How genes are organized along chromosomes, and even the chromosomes structures themselves can be different. Our Y-chromosomes are strikingly different from those of chimps, for example. This was a surprise to researchers, given the relatively short time our species supposedly diverged from one another. Rearrangements are also not included in the 1% number, and are difficult to quantify.
Gauger notes that these distinctions make a huge difference:
You can have two houses built of the same materials — two by fours, pipes, wall board, nails, wires, plumbing, tile, bricks, and shingles — but end up with very different floor plans and appearances, depending on how they are assembled. So it is with us. We may have almost the same genes as chimps, but the timing and distribution of their expression are different, and matter in significant ways.
Of course, these biological difference are not as important as the moral distinctions between us and our closest genetic relatives:
Going beyond the physical, we have language and culture. We are capable of sonnets and symphonies. We engage in scientific study and paint portraits. No chimp or dolphin or elephant does these things. Humans are a quantum leap beyond even the highest of animals. Some evolutionary biologists acknowledge this, though they differ in their explanations for how it happened.
Gauger makes another point I frequently emphasize:
In truth, though, we are a unique, valuable, and surprising species with the power to influence our own futures by the choices we make. If we imagine ourselves to be nothing more than animals, then we will descend to the level of animalism. It is by exercising our intellects, and our capacity for generosity, foresight, and innovation, all faculties that animals lack, that we can face the challenges of modern life.
Yes, we are exceptional. Own it!