Too Short for a Blog Post, Too Long for a Tweet 151

Here are a few excerpts from a book I recently read, "A Brief History of Everyone Who Ever Lived: The Stories in Our Genes," by Adam Rutherford.

The study of ancient humans was once limited to old teeth and bones and the ghostly traces of their lives left in dirt, but we can now piece together the genetic information of truly ancient humans, of Neanderthals and other extinct members of our extended family, and these people are revealing a new route to where we are today. We can pluck out their DNA to tell us things that could not be known in any other way—we can, for example, know how a Neanderthal person experienced smell. 

Retrieved after epochs, DNA has profoundly revised our evolutionary story. The past may be a foreign country, but the maps were inside us the whole time.

You are of royal descent, because everyone is. You are of Viking descent, because everyone is. You are of Saracen, Roman, Goth, Hun, Jewish descent, because, well, you get the idea. All Europeans are descended from exactly the same people, and not that long ago. Everyone alive in the tenth century who left descendants is the ancestor of every living European today, including Charlemagne, and his children Drogo, Pippin, and, of course, not forgetting Hugh. If you’re broadly eastern Asian, you’re almost certain to have Genghis Kahn sitting atop your tree somewhere in the same manner, as is often claimed. If you’re a human being on Earth, you almost certainly have Nefertiti, Confucius, or anyone we can actually name from ancient history in your tree, if they left children. The further back we go, the more the certainty of ancestry increases, though the knowledge of our ancestors decreases. It is simultaneously wonderful, trivial, meaningless, and fun.

We are sophisticated creatures, but our biology is fundamentally no different from a chimpanzee or a cat. But we have enormous intellectual powers that dwarf any other creature. Dolphins, monkeys, crows, octopuses all display facets of intelligent life—problem solving, tool use, complex communication abilities. We may well laud those mad skills, but they are still light years away from us in every single one of those categories. And so it might not be unreasonable to assume that our own faculties would be encoded in a genome that reflected those powers, at least in terms of numbers. 

But we don’t have more protein-coding genes than a chimpanzee. In fact, we have fewer genes than a roundworm. Or a banana. Or Daphnia, a type of minuscule see-through water flea the size of a grain of rice. Or indeed a grain of rice.  We have roughly the same number as our most useful genetic test species, the mouse, and a few more than our second favorite lab rat, the fruit fly. Just consider what is happening right now: I’m typing these words with a manual dexterity unique to living organisms, and I’m conceiving a story with reference to memory, deep understanding, creativity, and an ability to imagine the future, in which you are using all the same faculties in reading them, you’re imagining me typing right now. We estimate based on the number and density of connections between the neurons in our skulls that the brains you and I are using right now are the most complex objects in the known universe. Yet the code that underwrites that spectacular lump of gray meat is basically the same as animals that can do none of this.