Are Homo sapiens the only people?

Alien Anatomy

I've been watching the new NBC series The Event. So far it's hasn't been tell-all-your-friends awesome, but I've been finding interesting enough to keep watching.

The premise is that in 1944 a plane carrying aliens crashed in Alaska. While many of the aliens escaped, those who were injured  - and their leader, "Sophia Maguire" - were captured and interred in the secret Inostranka military base.¹ In the present day, there have been a series of strange events seemingly precipitated by the aliens who avoided capture.

Unlike the other recent "aliens are among us" series, V, the US government in The Event is more realistically suspicious of the aliens motives.  And unlike V's lizard-like aliens in beautiful human skins,  the aliens of The Event are primates like us.
While the series probably won't reveal the aliens' origins and purpose on Earth for some time, I think the possibilities are intriguing.

Here's the scene in the second episode that shows us what the US government knows about the aliens' biology:

Agent Lee:  Well, as you can see, outwardly they look very much like us, which could indicate a common ancestor, or even a parallel evolutionary process. But there are differences.

Now, initially, scientists were only able to detect small variations in their circulatory systems and blood composition. But over time it became clear that they age at a much slower rate that we do. Meaning that there had to be substantial differences we couldn't detect and that we didn't understand.

Now recent advances in DNA sequencing are starting to change that. We now know their DNA varies from ours by slightly less than 1%.

President Martinez: 1%? So they're people.

Blake Sterling: They're absolutely not. 1% is actually quite significant genetically. A chimpanzee's DNA differs from ours by only 2%, for example.

When I first saw that scene, my first reaction was "Wow, they are closely related to humans", followed by a puzzled "How are they not people?"   I suppose it all comes down to your definition of a "person.

It's true that a difference in genomic DNA sequence of even "slightly less than 1%" is significant.  It would definitely make the aliens a different species than Homo sapiens. They are not modern humans. But while they aren't human, they are more genetically similar to us than our close primate cousins the chimpanzees.

Reconstructed Neandertal family.  People?

Depending on the method you use to calculate similarity, human and chimp genomes differ anywhere from 1% to 6%.  That means you can't really compare the information thrown out in The Event. But the method of genome comparison that shows a 1.2% genomic difference between humans and chimps, shows a difference between the human and Neandertal genomes of 0.3%.

The ancestors of humans and chimps diverged roughly 6.5 millions years ago.  The ancestors of humans and Neandertals diverged between 500,000 and 800,000 years ago.  
I'd put the difference between the DNA of humans and the aliens of The Event somewhere between chimpanzees and Neandertals.  That means the ancestors the "aliens" would have split off from our human ancestors a couple of million years ago.

So what does that mean for the evolutionary origins of the aliens? 

Based on the similarity of their genome to humans, I'd say it would be extraordinarily unlikely that the aliens (or "aliens") originated anywhere other than Earth.  To produce intelligent humanoids more genetically similar to humans than other Earthly primates, evolution would have had to progress identically on Earth and on an alien world for many millions of years. That just couldn't happen – at least not without some sort of supernatural or superhuman intervention.

Where have the "aliens" been all this time? Perhaps they were moved from the Earth to another planet by more technologically advanced aliens.  Or maybe they've been living in an isolated enclave right here on Earth for a million years.  If it turns out they had been living all those millennia on a plateau in the South American jungle, on a tropical island in the Pacific, or in a valley high in the Himalayas, that would be a nice reference to the science fictiony "lost civilization" stories of the early 20th century.

I'm hoping that the origins of the "aliens" turns out to be both interesting and not entirely inconsistent with biology. Of course depictions of evolution in Hollywood unfortunately tend to be really bad, so I'm not going to be too surprised if the story ends up disappointingly silly.

So terrestrial origin or no, that leaves the question of whether the aliens are "people".

Maybe I've watched and read too much science fiction, but I consider any humanoid sentient being to be a "person". The Event's aliens are more similar to humans than Klingons or Vulcans or Minbari or Centauri or Gallifreyans - of course they are people!

Whether they turn out to be "people" with friendly intentions towards Homo sapiens remains to be seen.

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Watch episodes of The Event on Hulu. (available only in the US, and only for a limited time)

Further technical reading on human evolution:
• Cohen J. Relative Differences: The Myth of 1%.  Science 316: 1836 (2007)(pdf)).
• Green RE et al. A Draft Sequence of the Neandertal Genome. Science 328:710-722. (2010) (pdf))
• Smithsonian National Museum of Natural History: What does it mean to be human? 

Top image: Still from The Event episode "To Keep Us Safe". Agent Lee points out key features of the alien anatomy he knows so well.

Bottom image: Reconstruction of a Neandertal group. © Johannes Krause.  Source: Neandertal Genome Project Press Kit.



1. There is also a plot line with a computer programming genius trying to rescue his sexy fiance  (apparently a scientist of some sort), who has been kidnapped by a homicidal group whose origins and plans are unclear.  Their story line isn't nearly as interesting as the interactions between Sophia and the President Martinez.  Hopefully that will change.