How Sci-Fi Movies Get Mutants (and Evolution) Wrong
Image credit: 20th Century Fox
Recently, a large-scale genetics study examined DNA from 215,000 participants to determine how and where the human genome might be evolving. The results were not terribly surprising: genes that appear to affect human mortality are already well-known because they're associated with the risk of Alzheimer's disease, smoking habits, and cardiovascular disease. The longer you live, the more likely that you don't have a genetic predisposition for common diseases. The geneticist side of me thinks this is all very fascinating, but the writer side finds it rather ho-hum.
For a more thrilling exploration of mutation and natural selection, we need only turn to some cherished works of science fiction. Granted, there were some big swings and misses, such as the cringe-worthy Kevin Costner film, Waterworld. In it, the polar glaciers have melted, covering the world with water. Costner's character secretly has gills and webbed feet—enabling him to better survive in the watery environs—due to a "mutation." It's unlikely that a mutation would, by chance, give someone the exact traits needed to survive in a changed environment. In reality, nature tends to work by trial and error over a very long period of time.
No wonder that film bombed.
Next, let's talk about X-Men, specifically the 2011 iteration, X-Men: First Class. The central premise is that the superheroes (and supervillains) each get their unique abilities from a genetic mutation. The problem with this idea is that the human genome is already a sophisticated machine. New mutations in our genome are very rare, and they tend to have negative consequences – like cancer, cystic fibrosis, and a host of other diseases. Mutating the genome is kind of like putting a new screw into a car engine at random. There's a chance you might improve how the engine runs, but you're far more likely to break something. Or have no effect whatsoever.
Another issue is that the mutants in X-Men are discussed as if they're a separate species, possibly the next step in human evolution. Yet, as The Scientific American felt obliged to point out, unless the mutants were to preferentially breed with one another and somehow isolate themselves from normal humans, they are simply variations of our species, not the start of a new one.
Of course, no discussion of mutation and evolution in sci-fi would be complete without Planet of the Apes. We'll take Rise of the Planet of the Apes (2011) as sacrifice, since it was marketed with the tagline "Evolution becomes Revolution." The premise is that an experimental gene therapy designed to treat Alzheimer's transforms the brains of chimpanzees, rendering them super-intelligent. The chimp leader, Caesar, did not receive the therapy, however; his mother got it while pregnant. He got the smarts, as did a few hundred others who were exposed.
This illustrates a misconception about genetics that's common in Hollywood: the idea that acquired traits can be passed along to offspring. That pre-Darwin fallacy is called "Lamarckian inheritance," after biologist Jean-Baptiste Lamarck. Equally ludicrous is the idea that a few hundred chimps could develop high intelligence and speech overnight and soon threaten to outnumber humans on Earth. Realistically, mutation and natural selection are incredibly slow processes that happen across many generations.
There might be a super-intelligent chimpanzee out there. Lucky for us, chimps are slow breeders—one offspring every 4-5 years—so we probably have a few millennia.