XNA and Xenobiology

Today in Is It The Future Now?:  Synthetic DNA that can replicate and evolve.

Synthetic DNA is, in itself, not a new thing – it’s been around for about a decade now.  And these molecules aren’t self-replicating, exactly.  But they can “translate” DNA into XNA, and XNA back into DNA – and with high fidelity, as well.

It’s possible that it could have therapeutic purposes.  But what I find more intriguing is the fact that this punches a hole in the idea that only the nucleic acids of DNA and RNA can encode information.  There are more possible structures out there.  And, if things get particularly mad-sciencey, this could someday (likely in the far future) be proven by the synthesis, from scratch, of a novel XNA-based organism.

And who knows where it would go from there.

I can’t help but think that, whenever we find life on other worlds (and I’m pretty sure we will, if not on Mars then on Europa, and given the absolutely crazypants endurance of extremophiles, maybe even on Titan,) it will be mostly like terrestrial life.  That may be my natural cynicism at work – not wanting me to let myself get too excited for something wild and novel, not trusting the rest of humanity enough to be excited about the life even if it WERE incredibly different.  But these developments do give me hope that life elsewhere might not be just like us.

But it makes me wonder if it could make us just like them.  Would the plasmids of an XNA-based prokaryote be able to transfer to a DNA-based one?  Would the DNA-based prokaryote transform, if it did?  Bacteria play an incredibly important role in the human body, and recent research even suggests that our gut flora can not only break down our food but can even influence whether or not we are obese, and may influence such things as organ failure and various cancers.   Not to mention the fact that, even though they’re so much smaller and don’t take up much of our mass or volume, bacteria cells make up 90% of the cells in the human body, by number.

All these tested types of XNA were stronger, much more resistant to being broken down by biological nucleases.  What would these other structures be able to do?  What would they not have to face?  Would there be a reduced chance of mutations?  Would they be unlikely to develop cancer?  Would they have chromosomes like us, and would their telomeres – the nucleotide sequences that cap the ends of a chromosome, like an aglet to a shoelace – shorten like ours with every cell division?  If not, would they age?

It’s fascinating to think that something like the ending of War of the Worlds might be possible – only in reverse: xenobiological bacteria ferried from a returning probe or a meteorite quietly do some horizontal gene transfer with terrestrial bacteria, which transfer to still other bacteria, and eventually make their way into the bacteria within human bodies.  Altering our abilities to digest food or gain energy from it, to fight off infections by other hostile bacteria, or causing other presently imponderable changes.   An invasion and takeover in the truest sense, by aliens that cannot speak, cannot reason, and possibly cannot be stopped by any means we know.

The crux of Neil DeGrasse Tyson’s recent “Fascinatingly Disturbing Thought” is that, if humans differ from chimpanzees by only 1% of our DNA, a sentient alien species that is only 1% different from us would possibly see us as we see chimps – bumbling and virtually incapable of communication with us, but possessing an occasional surprising glimmer of very familiar intelligence.  As we’re amazed when chimps demonstrate the abilities of a human toddler, so a sentient alien species might be amazed when Stephen Hawking can perform the kinds of mathematics their toddlers can perform. We’re proud when our children learn long division; maybe they’re proud when theirs prove the Riemann hypothesis.   But, even though that’s slightly more familiar sci-fi territory, and indeed fascinatingly disturbing in its own right, at least it would be a relationship we could understand.  We don’t even fully know what our own bacteria are up to, and we’re symbiotic with them!

All this business with XNA might lead to fascinating and useful therapies, might lead to apocalyptic mad science of doom, or might just lead to nothing but some papers, some theories, and some speculative fiction.   Either way, it’s probably going to be interesting.

*I am not a biologist / bacteriologist / geneticist / scientist of any shape or kind, as is probably rampantly obvious.  And perhaps I should just have let the link speak for itself, instead of making a fool of myself by trying to ponder things I’m not versed in at all.  heh.  But, especially as I’m still getting this thing off the ground, it seemed… untoward, I suppose, to just drop a link from elsewhere here and say little of my own.  Thus the blather.  Sometimes, it’s pleasant to write through my speculations and ponderings – but perhaps that’s better saved for somewhere else?  Hooray for second-guessing myself!   Point being, I’m almost certain I will drop more SCIENCE in the future – it’s just the method I’m not entirely sure of.

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One thought on “XNA and Xenobiology

  1. evolutionandthings says:

    Please write more in science! I found this post incredible amusing. You took a finding from a recent paper and were able to imagine wildly fantastical possibilities.

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