Viruses, Variants and eVolution
Wow!
I just asked Google about “variant” and before I could blink, literally, I had more than 700 million pages at my fingertips - a lifetime’s worth of reading for something most of us never thought about before this spring.
Despite the seemingly sudden appearance of troublesome viral variants, like the ones slowing our exit from the pandemic, variants have been with us forever.
And variants aren’t always a bad thing!
In fact, the very same processes responsible for creating pesky viral variants are also the reason we’ve been able to evolve into a talking, empathizing, tech-savvy species.
(Well, some of us at least!)
When it comes to understanding how variants and evolution are merely two sides of the same coin, viruses are a great place to start.
Not disease-causing viruses but computer viruses which despite their capacity for everything from the laptop, blue screen of death to shutting down whole airlines and governments, are surprisingly simple - a set of instructions written in a language of 1’s and 0’s
I could, shh, detail the pattern of 1’s and 0’s making up the ILOVEYOU virus, a virus thought to have cost the global economy more than 10 billion dollars, but nothing bad would happen. Written on a page, those digits have absolutely no power as that piece of code has to enter a host i.e a computer if it’s going to cause chaos.
The problem is that all the instructions used by computer operating systems to enable them to do everything from opening YouTube cat videos to creating spreadsheets, are written in that same language of 1’s and 0’s.
Our computers can’t distinguish between the desirable number sequences making up their operating systems and undesirable viral sequences, so an infected computer reads and follows both the operating instructions and the viral directives with two main results - the computer malfunctions whilst copying and passing on that viral code to other computers, spreading the infection.
A virus that infects living things is no more alive than that nerdy series of 1’s and 0’s making up the computer virus. It’s simply a piece of code, written not in numbers but in DNA, or its close cousin, RNA.
Like the computer virus 1’s and 0’s, viral genetic material has no power until the virus enters a host, in this case, our cells. Because the instructions for the cellular processes keeping us alive, are also written in DNA and RNA, we have the same problem as with the computer virus - infected host cells can’t distinguish between the desirable genetic instructions and the unwelcome viral commands and therefore, follow them both.
Just like a virus-infected computer, infected cells malfunction whilst also duplicating and exporting the viral genetic code, and more and more cells become infected, and infectious!
(Hopefully, sooner rather than later our immune system outwits the virus, but that’s for another story for another day!).
There is though, one crucial difference between virus-infected computers and cells - computers are super accurate when copying viral code, and cells are not! In fact, cells are relatively careless when copying any type of genetic material, their own or that of a virus, and those errors cause changes in the code called mutations.
Some mutations change the look of a cell’s internal instructions a little but the directions still convey the same sense as the original - like when an American copies “colour” from a British article but re-writes it as “color”, we all still know what that means.
Sometimes though, the mutations alter the instructions to read in a very different way.
As viruses move through a population, they acquire both types of mutation in a process that might look something like this:
Take a cooking instruction that’s being passed from person to person down a crackly phone line.
The instruction is:
· Bake the pie at 400°F for 35 minutes.
The first error (mutation) changes the instruction to:
· Bake the pie at 400°F for 37 minutes. No biggie.
A second mutation adds to the first and the instructions now read:
· Bake the pie at 380°F for 37 minutes. Meh, it’ll still taste good
A third mutation and the instructions say:
· Bake the pie at 380°C for 37 minutes. Our pie is ruined!
As the SARS-CoV-2 virus (coronavirus for short!) has journeyed through millions of people, each made up of trillions of cells, many copying errors and mutations in the viral code have happened, creating numerous variants - close relatives of the original virus with a slightly different genetic sequence.
Many variants behave exactly like the original virus they evolved from, their mutations reading as “analyze” instead of “analyse” and “aluminium” in place of “aluminum” for example, but the message hasn’t changed.
But some variants, like the now infamous delta variant, are game changers.
This variant’s mutations have changed the virus’ instructions to the human host cells, ordering those cells to make a stickier spike protein that makes the delta variant 60% more infectious than other coronavirus variants.
But no, the virus didn’t try to become more infectious and it didn’t purposely set out to produce nastier variants, it’s all just down to chance mutations from careless copying.
Swiftly vaccinating populations does more than protect the people vaccinated today. It cuts down the number of times the virus is copied, lessening the likelihood of the virus randomly gaining the type of mutations that could make it more infectious or worse, resistant to the vaccinations that many of us anxiously counted down the days for.
All of which begs the question, why have we evolved with such a sloppy process for copying genetic material?
Because that error-strewn copying process responsible for bothersome viral variants, is also behind every one of the improvements to the human machine, all the evolutionary upgrades that have moved us out of the swamp to become the sophisticated humans we are today.
Throughout that epic journey, our ancestors were accidentally gaining random mutations in their own genetic information, those instructions written in DNA that cells need to survive and thrive.
Some of those mutations would have been decidedly unhelpful but most nasty mutations don’t get passed on to future generations because, well, they kill their owners before those owners have chance to produce children. On the other hand, random, advantageous mutations, ones that help humans to persist and prosper, are much more likely to be passed on to the next generation because typically, healthy people make more babies!
And so ultimately, love them or loathe them, viral variants and evolutionary improvements are two sides of the same, random mutations coin - we can’t embrace the benefits of one, without accepting the other!
Stay curious,
