Thursday, February 11, 2010

What we can learn from ancient human DNA

What can we learn about a person just from looking at their DNA? As our knowledge of genetics continues to grow, we may even be able to figure out what they look like. Research published in Nature looked at the genome of an ancient human using 4,000 year old hair that had been preserved in Greenland's permafrost. From looking at genes that cause known traits, we can learn a lot about his appearance.
  • Male
  • Type A+ blood
  • Brown eyes
  • Darker skin
  • Stocky body
  • Dry earwax
  • Shovel shaped teeth
  • Thick, dark hair
  • Tendency toward baldness
Okay, as an aside: Who is the lucky artist who gets to draw a reconstruction of an ancient human, or the feather patterns on dinosaurs? Is this someone's profession, or does a grad student do it? Maybe I can finally find a way to combine my art skills with my biology skills!

Anyway, it's pretty cool that we're able to learn about the actual physical appearance of someone just from their genes. Think about the implications in forensics cases when all that's left is tissue that's beyond identification. But that's not the thing that made this paper Nature-worthy. All of these genotypes are very similar to modern Siberians, which tweaks our current understanding of human migration. Jerry Coyne summarizes it well over at his wonderful blog, Why Evolution is True:
Oh, and the really interesting result is this: the DNA suggests that the individual had components of genes still present in East Asian and Siberian populations, but not found in modern-day Inuits or people from South and Central America. This suggests that there were two separate invasions of North America from Asia: the one that gave rise to native Americans, South Americans, and modern Inuit on the one hand, and that leading to the presence of Saqqaq in Greenland. Those latter individuals probably came across the Bering Strait, and then, hugging the Arctic, made their way eastward across North America and then to Greenland.

That conclusion is of course tentative because it’s based on only this single genome. Still, based on the sequence, and the tentative phylogeny showing that this individual’s ancestors split off from the ancestors of their closest living relatives (the Chukchis of eastern Siberia) about 5,000 years ago, anthropologists may have to revise their conclusion that there was one invasion of North America from eastern Asia around 18,000 years ago.

Very neat stuff! Though I would like to see a study using modern humans to see how accurate these sorts of predictions are. Take maybe ten individuals with various phenotypes, sequence their genomes, have the researchers try to reconstruct their appearance without previous knowledge of what they look like, send it off to an artist, and see how close we can get! I'm not sure what profound result this would show other than if this method is useful or not - just seems like a really cool thing to try out. Can't we do science for fun every once in a while?


  1. If this could be made very accurate, it could have real application in law enforcement. The ability to figure out what a suspect looks like just from DNA found at a crime scene would be wonderful. I'm sure the science is nowhere near there yet though.

  2. i think it's amazing, but on forensics, there is always that worry about transfer and such. for example, i could hug my bf, then go kill someone, and drop some of his hairs from my jacket or soemthing. iono, i'm just pointing that out, but still really amazing in identifying people who were around, remains, etc...

  3. Holy crap, it's prehistoric Val Kilmer!

  4. Dry earwax? I didn't know that there were genetic markers for earwax.

  5. According to Wikipedia, the field is called 'forensic facial reconstruction', within the field of 'forensic archaeology.' It's in a bag with police artistry, and requires mucho mucho background in drawing and additive sculpture (building up a structure rather than carving it out). PBS' NOVA featured some professionals who worked on Ardi.

  6. outside the 'forensic facial reconstruction' ecorona list above the other stuff is a field called Scientific Illustration, it covers a lot of varied things including detailed orthographic projections of type specimens, visualizations of scientific phenomena that occur at distances or scales that don't lend themselves to photography (distant stars, atomic or quantum interactions), stuff like that.

    The field is basically an art discipline, with some basic science classes added in so the artist has a better understanding of what the scientist is talking about.


    Carl Buell is a really well known scientific illustrator that has done alot of walking-while type reconstructions. Its basically a full time profession. I tried to get them to let me take a scientific illustration class, but I wasn't allowed.

    We've also got a fantastic invertebrate illustrator working in a lab, too:

    So there is always money to be made!

  8. I love Carl Buell's work!

    I'm also a fan of Heather Luterman: