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  • 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

  • changesapparently 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.

In comic books and superhero movies changes to genetic material lead to some prettttty

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Cellular Cannibalism May Have Led to the Evolution of Everything, Including Us

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    joey joey に公開 2021 年 04 月 18 日
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