In which I invite them in

Although engaging with the public about science is famously not about – heaven forbid – ‘teaching’ it, the two endeavors do share some common strategies. I’ve been organizing and executing a lot of undergraduate educational sessions these past few terms, and I can report that the humble analogy is equally effective in both spheres.

It’s true I sometimes weary of science similes and metaphors, especially when they stray into overtrodden cliché territory. The DNA-as-letters/chromosomes-as-books/genome-as-library trope, once so apposite and fresh, has been trotted out so many times by the unimaginative over the years that is has become almost greeting-card sickening. Other metaphors are so engrained in our science vocabulary that people have even forgotten they were metaphors in the first place – concepts such as ‘immune surveillance’ or ‘protein translation’, for example.

Still, I can’t resist a really nice analogy, as long as it’s evocative and – above all – original. So I tend to collect them as I find them through life’s little happenstances.

Yesterday when I was leaving the local high street home improvement superstore with my family, I was accosted by a wild-eyed, cheap-suited man who’d set up temporary shop in the foyer next to a folding table covered with leaflets. His suit wasn’t nice enough to be a Jehovah’s, although there was something of that vibe about him. In a fraction of a second I’d analyzed the leaflet being fanned enthusiastically in my face and had him pegged as a double-glazing salesman.

In a moment of terrible weakness, I decided to accept a leaflet. After all, there are a few single-paned windows in the back of our new house and Richard and I have discussed replacing them at some point in the future. What harm could one leaflet possible do?

As I tried to walk past with the brochure, the man actually grabbed me by the arm and informed my that I couldn’t get the forty per cent discount without registering. Heart sinking, I realized I was falling into a trap – a proper fruit-fly-lodged-into-congealing-jam trap – but I somehow couldn’t stop myself from scribbling my name onto his form. And, when prodded, almost robotically, my mobile phone number. I was that mesmerized maiden, inviting the vampire past my threshold. Except vampires are a lot more charming.

Desperate to escape now, I attempted again to pull away.

“Stop!” the man barked imperiously. “We need a second phone number!”

“What? Why?” Fortunately I couldn’t remember my new land line number yet, and told him as much. The fly, managing to pull half of its legs out of the jam, soon starts to wake up and sense freedom.

“What about the gentleman’s?” he barrelled on, looking over to where Richard, with a don’t-you-fucking-dare expression, was holding our squirming son, who had started to howl with hunger and fatigue. Or maybe he just doesn’t like double-glazing salesmen.

“I’m not going to give you another phone number!” I had to shout to be heard over toddler indignation. “Why do you need more than one?”

As he was muttering something about ‘security’, drowned out by unearthly shrieking, we finally managed to make our escape. There was no way I was going to give my custom to any company that would rather bully a potential customer than allow her to get her screaming baby home to lunch.

As the morning dawned foggy and morose, I knew I was in for a protracted siege. Sure enough, four missed calls from the number on the leaflet between 9 and 11 AM – but no voicemail. Don’t they comprehend that some people cannot take private calls at their places of work? (If you’re interested in science analogies, you can start paying attention again now.) I used my iPhone to block the caller. About 20 minutes later, another call – the same number except the last three digits. The second time this one called, I blocked that one too. Starting at 2 PM, I started to get calls from unknown numbers. Including one just now, as I type these words.

The stupid, make it stop

But it wasn’t all bad. Actually, I started to realize, it was a lot like host/pathogen interactions. When you co-evolve over many millennia with an ancient enemy, as humans have done with bacteria, viruses and other parasites, you are constantly shifting to stay one step ahead. We have developed an elaborate immune system to keep out invaders – so elaborate that we are struggling to summarize it all even at a basic level for our students this term. But the pathogens seemingly shrug such barriers off and, often in no time at all, have mutated to get around our defenses.

Imagine a flu virus, which is covered in coat proteins that can latch on to our vulnerable cells. Our immune system amplifies antibodies that can stick to these virus attachment proteins and neutralize them – as my iPhone blocked the first number. But the virus, with its sloppy genome copying system, can mutate to make subtle variations in its coat proteins – subtle variations that the first antibodies no longer can recognize. That’s their related number, a few digits different, that my iPhone failed to block. I block the second number – as the immune system rebounds to generate new antibodies that can bind to the revised version of flu coat proteins. And the flu counterattacks: just as the company switches to phones that will not trigger caller ID, flu periodically makes more major coat protein changes – the so-called ‘antigenic shift’ that can sometimes be the harbinger of an epidemic. And so on, ad infinitum.

In summary: parasites…vampires…double-glazing salesmen. You get the idea.

This will be on the exam.