In comic books and superhero movies changes to genetic material lead to some prettttty
strange capabilities!
But in reality, could altering our genetics help us rapidly evolve?
Unfortunately for those of us who live in the real-world, expression of large mutations
requires evolution: generations of iterative selection of a specific change.
So, sorry, no single exposure to radioactive sludge is gonna turn you into a mutant turtle
with martial arts skills.
We rarely get to see the results of the mutations that build up in our DNA over a lifetime.
But, if you let yourself start to think about the fact that the complexity of life we all
take for granted started out as a collection of single celled organisms -- we all kinda
look like superheroes.
So how does a simple cell get to be a complex creature like you and me?
Well, one individual cell can’t, but generations of its descendants, over millions of years,
making mistakes in replication and reproduction, of begging, borrowing and stealing similar
evolutionary solutions, suffering a harrying gauntlet of selection pressures and environmental
changes … apparently did.
Early on, like, 1.4 billion years ago early on, a jump in evolutionary complexity may
have occurred when a simple single cell engulfed another simple single cell.
These two cells likely had some genetic variability between them and so a more complex cell was
born.
The process of one cell absorbing another in its entirety is called phagocytosis.
When that happened, the ingested cell didn't get chewed up and digested -- instead, it
formed a beneficial relationship, with its devourer.
Endosymbiotic theory suggests that post phagocytosis, the resultant symbiotic relationship was so
successful (over generations) that the engulfed cell eventually relied on the host cell to
provide the resources it needed to survive, and the host cell likely gained the benefit
of any superpowers its prey may have evolved, like the ability to generate energy or photosynthesize.
The mitochondria in our own cells and the chloroplasts required for photosynthesis in
plants may have started out as bacteria with extraordinary abilities that were engulfed
by other cells.
These compartments still have minimal circular genomes that look like bacterial genomes,
evidence for the hypothesis that they were once independent.
I wish I could say that this approach to symbiosis worked in complex systems but sadly it is
limited to simple, single celled organisms.
So if you were wondering, eating a spider, even a radioactive one, will not give you
the ability to swing around skyscrapers and climb walls on your fingertips.
There is evidence, however, that more complex genomes can benefit from contact with foreign
genes.
One example of this is a protein called Arc.
Arc works very similarly to the viral coat proteins of retroviruses like HIV.
It assembles together to create an envelope that carries RNA between cells.
This is how retroviruses infect their hosts.
In mice and possibly in humans, the behavior is essential for memory formation.
It’s likely that our version of Arc came from a virus that infected a cell long ago
-- and now we can’t form memories without it!
Why?
Scientists aren’t yet sure -- but our neurons need the ability to shuttle RNA back and forth
like viruses.
The capability is evidence of horizontal gene transfer -- vertical gene transfer is direct
inheritance, horizontal is when weird stuff like this happens.
There is an obvious evolutionary benefit to creating diversity through random genetic
events and nature has many mechanisms through which to ensure that it beta tests a wide
variety of genetic variations.
The lucky ones will persist in the population and likely confer some survival and/or reproductive
advantage to it’s carriers, and we may never know they’re there.
It is unlikely that a random event will lead to the development of superpowers overnight,
and we’re still waiting for modern gene therapy to go mainstream.
But, right now, it is highly likely that you are already a mutant experiment of nature
who will pass down the primitive building blocks of some superpower to future generations
of your offspring.
For more on the secret lives of cells, check out this video.
And Fun Fact: human male mtDNA self destructs upon fertilization so we inherit 100% of our
mitochondrial DNA from our mothers The powerhouse of the cell, ladies.
Thanks for watching Seeker.