In "X-Men: Apocalypse," hitting theaters Friday (May 27), a big, blue powerhouse called "the world's first mutant" threatens humanity with his fearsome abilities. Though real-life mutations haven't given people apocalyptic powers (yet!), science has hinted at some of the human lineage's "first mutations."
From genes implicated in the ballooning of the human brain to mutations associated with the modern diet, genetic tweaks to our human ancestors helped make this species the dominant one on the globe — at least until an Apocalypse comes along.
Here are some of the "first mutants" in humanity's prehistory.
Big brains
In the movies and the original comic books, the X-Men follow the lead of Professor Charles Xavier. "Professor X's" mutant telepathy offers an appropriate sci-fi echo of some of the real mutations that set humans apart in prehistory: genetic changes that allowed for big, powerful brains. [10 Features That Make Humans Special]
Research into the fully sequenced genomes of gorillas helped to identify one such gene: Called RNF213, it showed accelerated evolution in the branch of primates that includes humans, gorillas and chimpanzees, said Aylwyn Scally, a geneticist at the University of Cambridge in England, who led the research.
"What we mean [by accelerated evolution] is not just that it's accumulated a lot of differences," Scally told Live Science. "What we're looking for in accelerated evolution are changes that really do change the protein sequence."
And that's just what happened with RNF213, he said. What's more, other researchers have linked deficiencies in RNF213 with moyamoya disease, which involves decreased blood flow to the brain. This suggests RNF213's evolution helped facilitate the large blood flow needed by big, energy-hungry brains, Scally said.
In general, Scally and his colleagues found that genes related to brain development and sensory-information processing showed accelerated evolution in the human lineage. In fact, RNF213 is just one of many genes, such as "Frizzled-8" and ASPM, linked to brain-size evolution in humans, Katherine Pollard, who studies human genetics at the University of California, San Francisco, told Live Science.
Powerful computers
Of course, human brains aren't just big. Like Professor X's brain-boosting "Cerebro" computer, the real human brain is a powerful processor. And scientists have also identified a few mutations that might have helped to juice up the human computer.
Disease studies revealed that a DNA region called HAR1 shows activity in the human brain, which means the DNA is turned on, and not suppressed in brain cells. Specifically, during brain development, this region shows activity within neurons that help lay down the pattern of the cerebral cortex, the gray-matter seat of consciousness, language and memory. Moreover, early studies comparing the human and chimpanzee genomes identified HAR1 as evolving rapidly in humans after the human-chimpanzee split.
"We thought the most important chimp-human differences would be these sequences that had been frozen throughout evolution … but then changed just in humans," Pollard said. Those regions are the HARs (human accelerated regions), and HAR1 was the fastest-evolving of those regions in humans, Pollard told Live Science.
Research has linked another gene, FOXP2, with an important accomplishment of the human brain: language. Individuals with FOXP2 mutations have speech difficulties, and the gene was identified by Pollard as another evolutionary hotspot.
"So that's very exciting and suggests that it could have a role in our language abilities," Pollard said. "It's interesting because that region of the genome, both in its regulation and the gene itself, are quite different between humans and chimps."
Conquering mouths
Professor X isn't the X-Men's only claim to fame, just as the brain isn't the be-all and end-all of human prowess. Like fan-favorite Wolverine, whose mutant "healing factor" tamps down toxins, humanity owes some of its success to an ability to ward off sickness. [11 Surprising Facts About the Immune System]
The migration of ancient humans across the globe, over the period from 200,000 years ago to 18,000 years ago, suggests they could eat a wide variety of plants, said Nathaniel Dominy, an anthropologist at Dartmouth College. Research by Dominy and colleagues suggests that a gene called AMY1 helped make such a wide-ranging diet possible.
"One of the really extraordinary things about modern humans is … how we rapidly colonized the rest of the world," Dominy told Live Science. And the only way that could have happened "is if we were able to adapt to local conditions, and that would have entailed the experimentation of new, local plant foods."
Plants have defenses, though, which often result in diarrhea, sapping unlucky diners of nutrients. AMY1, which codes the enzyme that digests starch, may have helped early humans obtain the glucose from plants before getting sick, Dominy said.
That's because modern humans have more copies of AMY1 compared to human relatives (chimps and bonobos), and in humans and close relatives, AMY1 is expressed in the mouth, not just in the intestines. This means people can begin effectively digesting starch as soon as they take a bite — long before the meal hits their intestines and could make them sick, Dominy said.
It's complicated
Despite these exciting findings, geneticists have gotten more conservative in their predictions about human evolution, Pollard said. In other words, just as the X-Men franchise oversimplifies mutation, early research into human genes may have oversimplified how human evolution occurs.
Linkages like that between HAR1 and the brain's cortex are based on "guilt by association" evidence, Pollard said. "It's in the right place at the right time to have that effect," she said. Actually proving such an effect has been more difficult, she said.
More recent work has dismantled the idea that a single gene may encode intelligence, language, bipedalism and other complex human traits, Scally said.
"With complicated phenotypes, like intelligence, it seems those are also very complicated at the genetic level," Scally said. "It's a very marginal change across a whole bunch of genes." Phenotypes are the traits of an organism.
In addition, many scientists have focused their attention on regulatory regions of DNA, which turn other genes on and off, Pollard said. That work "suggests that humans and chimps aren't different because we have different building blocks or proteins, but that we're using those same building materials in different ways," she said.
But coming to terms with those complications is just part of the process of unraveling humanity's genetic background, Scally said.
"We are groping towards that question of what makes humans unique," he said. "But we're still fairly near the beginning of that journey."
(For more on "X-Men: Apocalypse" and the X-Men characters, check out Live Science's sister site Newsarama. There, you can find a review of the new movie, a countdown of the worst X-Men villains, another slideshow of the worst things that have ever happened to the X-Men and more on the X-Men.)
Original article on Live Science.
