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.
Comments