Don't let the cutesy animation fool you, these guys rock the house.
John Oliver also did a show recently about CRISPR that reminded me how cool it is & how much I wanted to write about it. His segment is really quite informative about the social context of it, but today I'm gonna bite into the nuts & bolts a bit.
CRISPR stands for "clustered regularly interspaced short palindromic repeats," because we found them and then named them before we figured out what they did, because that's how science works a bunch of the time. We named them because, when we were looking at bacterial DNA, we found these weird structures that seemed kinda out of place (or possibly a waste of space). So there are these repeating sequences of base pairs, they read the same forward & backward, they're fairly short, they're regularly interspaced, and we find them clustered together.
These structures occur naturally in bacteria & archaea, where we first found them, and it took us a while to figure out what they did because, surprise, they're one part of a system and not a whole enclosed thing-in-a-vacuum on their own. What happens is, when bacteriophage viruses do their thing and inject their code into a bacterium to convert them into factories for making copies of themselves (which is, like, all viruses ever do), that bacterium can "recognize" the virus' code if one of its ancestors survived an attack from this virus. Or, well, one of its less-successful cousins, at any rate.
When that ancestor bacterium survived the initial attack all those generations ago, it took a chunk out of the virus' code and saved it for later, like a cheese puff that falls between the cushions of your couch. Well, not exactly like that, because it's less like a snack and more like a hoarder saving leftover IKEA parts "for a project." Except this project actually gets done, so maybe less like that and more like saving memorabilia in a box so that you can... y'know what? I'm done with analogies for now.
Anyway, when a sufficiently-similar virus comes by once again, and once again injects its code into the bacterium, the bacterium now has a mechanism for recognizing that code and disposing of it: a "CRISPR-associated" (cas) enzyme snags the CRISPR segment and compares it against all the various bits floating around, and when it finds a match, BAM! It's clobberin' time, as the kids haven't said since... since I was a kid, really. Even then. I think I just said that 'cuz my dad did.
Now because that cas enzyme is able to take any CRISPR chunk & do the slice-&-dice with it, this means it's not limited to what's currently in the bacterium's DNA. It's not even limited to whatever will or might ever be in the bacterium's DNA. In fact, we can yank out that cas enzyme and give it whatever we want. We've even found a way to make it add or replace, not just delete, DNA sequences arbitrarily, even down to a single base pair. Yeah. Chew on that for a minute. Swallow hard.
So, as summed up in the Last Week Tonight clip linked above, CRISPR tech can be used to arbitrarily copy & paste code into or out of host DNA. Anyone got the over-under on whether we'll use this power for good or for evil? I know we're already using it for stupid: Josiah Zayner, the "biohacker" who injected himself with a DIY CRISPR kit he sells online, was the target of Oliver's ridicule for pulling that stunt. But now Zayner is facing the regret that a lot of people get from high-visibility stunts that don't go the way they want, and he's awkwardly considering the ethical ramifications in stunted high-school terms for what seems like the very first time.
Forget performance-enhancing gene edits, forget designer babies, forget genetically engineering deafness or dwarfism out of existence, and forget people scrambling for the latest and greatest splice kits like iPhones - what if we created a real-life Redlight virus? Dollars to donuts that's what white supremacists would do first, and I wish like Hell I was wrong.
Fortunately - I can't believe I'm typing these words, but here we are - fortunately, there are problems with this fascinating and exciting new technology that will keep us wary of any widespread or recreational applications for a long time. When CRISPR is used in humans and/or other species with the p53 gene (which guards against cancer, thank you Metal Gear: Solid), that gene goes into action and mashes the self-destruct button, scuttling the cell. Without the p53 gene, you've got a cancer bonanza on your hands, because it turns out cancer actually kinda happens all the time and your body just handles that shit. So the way CRISPR works is pretty much directly antithetical to our anti-cancer defense, which means that if it ever does work then you've got a cell that's prone to cancer, and spreading the newly-edited cancer-prone genome around in your body is probably the only thing worse for you than smoking or skinny-dipping in the wet well of a nuclear reactor.
Unfortunately - again, I can't believe I'm typing this - unfortunately, technology only gets better, faster, and cheaper with time - and we've already got the "cheap" part down (did I mention Josiah Zayner and his bonkerballs DIY CRISPR biz?). So really, it's only a matter of time until we have to deal with the best and worst that will come of this, on a massive scale. Which means we should probably start teaching bioethics in high school, like, yesterday. And also coming up with ideas for what to do if shit goes way the Hell wrong.
Good luck, motherfuckers.
No comments:
Post a Comment