Why Are There No Real Life Superheroes?
The X-men, humans who are born with genetic mutations that give them superhuman abilities, have captured the imagination of millions of people. Why are there no real life X-men? There are tremendous athletes all around us, but still even the fastest person in the world, Usain Bolt, is only a shade faster than his competitors . Compared to physically active adults, Bolt is at most twice as fast, but probably less . Like Wolverine from the X-men, starfish can regenerate a limb that is chopped off (and in some cases grow a whole new body from a limb) .
Why is it that no human has been born that is 5x faster than the rest of us? With 7 billion people there are a lot of opportunities for mutations. Why is there not a little girl or boy out there who can chop a finger off and grow it right back?
Fruit Flies With Super Speed
In 1996, a scientist set up a simple competition for his fruit flies. The flies had to race a fixed distance flying against a wind tunnel. Each time, the winners (fastest 4.5%) were selected and bred together to create the next generation of flies. Over time, the flies achieved a remarkable increase in flight speed – getting almost 100 times faster in the space of 100 generations. One generation takes only about a week, so the whole process took less than two years .
Just as fascinating as this increase in speed though, was the fact that the increase was very smooth. It was not as if researchers managed to mutate a single gene that gave super speed, but actually each generation the new set of flies picked up a handful of small changes that increased their speed bit by bit.
The Vast Majority of Genetic Changes Cause Minute Differences
As scientists have collected DNA from hundreds of thousands of people and compared it to common traits like height or physical fitness, the same pattern that has begun to emerge is that many hundreds, if not thousands of genetic variants contribute small amounts to the differences we see . This means that the chances of a person being born with hundreds or thousands of genetic variants that are the ‘fast’ version of the variant are very small.
So Super People are Unlikely to Happen Naturally, But Can We Create Them???
The concept of genome editing as a method of ‘bio-hacking’ has become a subject of worldwide interest and debate. Scientists in the UK, China, and Sweden have received permission to do research on genome editing in developing human embryos (for basic research, not yet for any medical application) . But making changes to the genome (whether at birth, or within a specific tissue such as the muscles or brain) to engineer strength, speed, intelligence, or resistance to disease is still far from mainstream for many reasons. First, a big part of genetics to date is building a ‘catalogue’ of genetic changes that influence traits – for almost all traits, these catalogues are incomplete. Second, genetic variants that have an impact on one trait (for instance, height) may have impacts on other traits as well (for instance, heart health).
Before there is any hope of safely using genetics to ‘biohack’, we need to better understand the connection between different traits. Besides the scientific hurdles, there are ethical issues of to what degree we should alter the genetic code. Genetic screening is already widely used to help families with a risk of genetic disorders avoid passing them onto their children, but is rarely extended beyond these life threatening cases. While you should not count on seeing (or becoming!) a lab-grown superhero anytime soon, the conversations about what is possible and ethical should involve everyone, not just the scientists and medical professionals working on the research. Feel free to leave a comment below with your thoughts!
Materials provided by Heterogenous. Note: Content may be edited for style and length.
Patrick Short is one of the co-founders of Heterogeneous and is particularly interested in understanding the genetics of rare diseases. Patrick grew up in North Carolina in the United States and now lives in Cambridge, UK and is based at the Wellcome Trust Sanger Institute on the Genome Campus.