Monday, October 18, 2010

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.


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.


Tracy said...

Seems like the typical show for NBC lately. In a way they are kind of turning away from the comedy series style of show and starting to go into more serious drama type series. Its awesome though that they are really bringing science fiction to life.

Athena Andreadis said...

Very interesting, Peggy! I was totally unaware of this, thank you for pointing it out.

I agree with you that they couldn't be of any origin but terrestrial. As to people -- that depends on definition. They're obviously members of the hominin family. The rest depends on the iron rule of ability to interbreed.

mrcreek said...

There isn't a particularly good reason to define "person" by means of sequence divergence. One could theoretically engineer a human with billions of bases of extra useless junk DNA, who would thus be more than 50% "genetically different" from the rest of us but phenotypically indistinguishable. The only reason we can make a clear distinction between "human" and "non-human" in our minds is because all of the steps between human and chimp are gone. If they were still around, there would be no obvious boundary of personhood, with plenty of resulting ethical and political conundrums (which have been underexplored in science fiction, in my opinion). The ability to interbreed is irrelevant. If it were discovered that an isolated group of humans were reproductively incompatible with the rest of humanity, but shared our intellectual and emotional capacities, there is no question in my mind that they would be "people" in every moral and social sense.

Athena Andreadis said...

Genes also control brain wiring; embryo viability is merely a practical measure of such divergences, which are more than skin-deep. So the interesting question is if they would indeed share our capacities and assumptions.

Make no mistake, I don't think that they should share everything with us to be fully sentient. But "people" is a different issue.

And not so incidentally, "junk DNA" is everything but. The term hails from the days when we were aware of only coding DNA functions. We know much more now about alternative splicing, miRNAs and chromatin states -- which influence outcomes as decisively as proteins that arise from "coding" DNA.

Peggy said...

Tracy: NBC seems to go in cycles where sometimes they favor dramas, and other times they favor comedies (which are cheaper to make). Looks like they're trying dramas again since the Jay Leno-every-night schedule didn't work out so well.

Peggy said...

Athena: Would other sapient beings really have to share our "capacities and assumptions" to be considered people?

I would argue that other humans often don't share the same capacities and that assumptions and workings of interpersonal relationships can vary widely from human culture to culture.

I personally feel that sapient beings would have to be extraordinarily different from humans to not be considered "people". I would definitely include other intelligent hominids so closely genetically related to Homo sapiens that they are also likely in the Homo genus.

Jeremy said...

My suspicion is that they are not aliens, but time travelers from the very distant future.

Peggy said...

Jeremy: It wouldn't surprise me if that's their secret. Perhaps they are refugees from the future, which has been made unlivable by events in our present?

Athena Andreadis said...

Well, Peggy, sometimes I do think that humans are several species that simply have the ability to interbreed!

More seriously, the term "people" has at least two shadings. It's an informal plural of human (my use). It's also the plural of person (your use). It's the plurals that are sowing confusion! I think we agree that you don't need to be human to be a person and that Homo sapiens cousins were people.

Peggy said...

When (and if) we meet other sentient beings, I think we're going to have to overhaul the language. There are so many assumptions built in to words like "person" and "people" that they many not be adequate.

Anonymous said...

Yeah, I was thinking that they were either from the future or that they were explorers/anthropologists from an alternate timeline Earth.

On the H.sapiens as the only people question - considering recent history (as in the last 500 years or so) of the political nature of inclusiveness, or lack thereof, of the category of personhood; the government types are already on extremely shaky ground morally, politically,and whatnot in declaring yet another group of seemingly less-powerful sapients as not people.

Esebian said...

I always liked the thought that they're an alternate version of humans from a parallel universe where evolution took a slightly different path causing rather big differences in their genotype (and maybe a technologically more advanced culture), but developed a similar body structure due to identical environmental influences on their Earth.