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What makes us human?

(Illustration for Time by Tim O'Brien)

What Makes Us Different?

Not very much, when you look at our DNA. But those few tiny changes made all the difference in the world.

In this compelling, interesting article in today's Time Magazine, a team led by molecular geneticist Svante Paabo in Leipzig, Germany, will announce a stunning achievement: the sequencing of a significant fraction of the genome of Neanderthals who are far closer to us genetically than chimps are. And though Neanderthals became extinct tens of thousands of years ago, Paabo is convinced he's on the way to reconstructing the entire genome of that long-lost relative, using DNA extracted from a 38,000-year-old bone.

For most of us, it's the grand question about what it is that makes us human that renders comparative genome studies so compelling. According to scientists, evolution is a random process in which haphazard genetic changes interact with random environmental conditions to produce an organism somehow fitter than its fellows. After 3.5 billion years of such randomness, a creature emerged that could ponder its own origins—and revel in a Mozart adagio. Within a few short years, we may finally understand precisely when and how that happened.

You don't have to be a biologist or an anthropologist to see how closely the great apes—gorillas, chimpanzees, bonobos and orangutans—resemble us. Even a child can see that their bodies are pretty much the same as ours, apart from some exaggerated proportions and extra body hair. Apes have dexterous hands much like ours but unlike those of any other creature. And, most striking of all, their faces are uncannily expressive, showing a range of emotions that are eerily familiar. That's why we delight in seeing chimps wearing tuxedos, playing the drums or riding bicycles. It's why a potbellied gorilla scratching itself in the zoo reminds us of Uncle Ralph or Cousin Vinnie—and why, in a more unsettled reaction, Queen Victoria, on seeing an orangutan named Jenny at the London Zoo in 1842, declared the beast "frightful and painfully and disagreeably human."

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And sometime in the next few weeks, a team led by molecular geneticist Svante Paabo of the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany, will announce an even more stunning achievement: the sequencing of a significant fraction of the genome of Neanderthals—the human-like species we picture when we hear the word caveman—who are far closer to us genetically than chimps are. And though Neanderthals became extinct tens of thousands of years ago, Paabo is convinced he's on the way to reconstructing the entire genome of that long-lost relative, using DNA extracted, against all odds, from a 38,000-year-old bone.

Laid side by side, these three sets of genetic blueprints—plus the genomes of gorillas and other primates, which are already well on the way to being completely sequenced—will not only begin to explain precisely what makes us human but could lead to a better understanding of human diseases and how to treat them.
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Read full article here.

posted by Annamarie at 4:17 PM