Mutants Among Us! Can Humans Evolve?

In the TV show Heroes, hundreds of people discover that they have superhuman powers.  My favorite power from the show is Hiro's ability to master time and space.  This is the only power in all of science fiction that I would prefer to Nightcrawler's poof (from X-men).  Just like X-Men, Heroes explains that these special individuals are a more evolved form of human.  Is this how evolution happens?  Is it possible to wake up with a genetic mutation that gives you added powers?  Do mutants usually wear black?


Yes, this is one way that evolution happens.  No, you will never wake up with a new ability due to random mutations in DNA.  And if you think all mutants wear black, you're too old to remember the Teenage Mutant Ninja Turtles.  Let's break it down.

Genetic Mutation

Mutations happen constantly in one form or another.  Every time that your cells divide, your entire genome is copied so that the new cell can have a complete set of genes.  The tiny biological machinery involved in copying DNA works very quickly to duplicate our 3 billion basepairs.  (See the video below for an example of the incredible speed of our internal molecular machinery.)  (Click here for a refresher on DNA bases.)

Let's say a skin cell on the back of my earlobe just started dividing this morning.  By tomorrow morning, its DNA will be completely copied and sorted so that the new cell ('daughter cell') will have its own complete set of DNA.  In one particular region, my DNA reads GCCAGCC, but in the hustle and bustle of replication, a mistake was made.  That region now reads GCCGGCC in the daughter cell.  I'm now a mutant!

Chances are good that this mutation will have no effect on me for two reasons.  First, less than 2% of my genome is used as a template for proteins.  (Click here for a refresher on how DNA determines proteins.)  It's like a bird pooping over a playground - the odds are that it will slip into the grass, leaving the children blissfully unaware.

Rarely, a bird can land a lucky shot.  I myself have been whitewashed in recent years.  When a mutation does occur in a portion of the genome that codes for a needed protein, there is still a good possibility that the mutation won't make a big enough difference to cause any notable changes.  It's possible that the protein will never be expressed, such as a necessary liver protein that gets mutated in that reckless earlobe cell of mine.  Or perhaps the change is so small or insignificant that it makes only a small difference to the normal daily functions of my earlobe cell and I never notice that it grows a little slower and dies sooner than the rest of my earlobe cells.  Most of our mutations are harmless like this.

Mutations Cause Cancer

There are also deadly mutations.  Mutations can be much bigger than a simple change from A to G.  Things like UV rays and carcinogens can find their way deep into cells to break and kink DNA irreparably.  Our cells have repair machinery to correct small mutations and self-destruct machinery in case things go horribly wrong.  If a mutation occurs in the DNA that codes for the repair or self-destruct machinery, the cell has no defense against further mutation.  Without the proper repair and self-destruct machinery keeping things in control, the cell can grow and divide uncontrollably.  Each of its daughter cells have the same mutations and continue unhampered growth, forming a tumor, the beginning of cancer.

Mutations Cause Evolution

Mutations can be undetectable and they can be deadly.  Can't mutations be bioawesome?  What about Hiro, Nightcrawler, and Leonardo?  Can humans evolve?

Humans have evolved, do evolve, and will evolve.  Unfortunately for would-be super heroes, evolution occurs more slowly and in less exciting ways than movies want us to believe.  But it does happen, and it's usually caused by simple mutations that spread in subsequent generations.  For instance, a few hundred years ago, the bubonic plague devastated Europe.  Many people survived because they had a slight mutation in one gene (CCR5).  Since most people without the mutation died, what started as a random mutation has spread into nearly 10% of people with Northern European ancestry.  In the last 15 years, this gene has been found to confer resistance to HIV and smallpox!

So what about stopping time, teleportation, and talking, fighting, skateboarding turtles?  I can tell you now that modern physicists and biologists would say that bending time or space is completely outside the abilities of a biological organism.

But mutant ninja turtles could happen.  For millions of years, organisms has been evolving one step at a time.  Most mutations aren't helpful for the organism and therefore lead to early death or decreased offspring.  Every so often, a mutation arises that helps the organism and its offspring succeed in their environment.  These mutations will spread in subsequent generations.  Barring some rare events, IF turtles could evolve one step at a time toward being ninjas, AND each step increased the turtles' success in their environment, the mutations would spread and through the population; further mutations following the same two conditions would be added to the first mutations until you eventually have turtles that wear headbands, eat pizza, and dual-wield nunchucks.

Forcing Evolution

We are approaching an exciting and controversial point in biotechnology.  Human-driven evolution is on a distant horizon.  Besides cyborg-type technology, scientist-directed gene therapy in human embryos (or even adults) could lead to manmade mutations.  These may help us against diseases, change our behavior, or even give us cat-like night vision.  But don't count on flying unless you're willing to grow some very large wings.