The Compatibility Gene by Daniel M Davis: "I am very rare but my wife is rather common"

The scientist Daniel M Davis has told the story of genetic compatibility - and the rejection that is its opposite - with great insight and decades of research. It's a field that may yield significant treasures in the decades to come.

The Compatibility Gene
Daniel M Davis
Allen Lane, 256pp, £20

“I am very rare but my wife is rather common.” This is not a sentence that would normally endear an author to you, let alone make you feel a little sorry for him. The thing is, it’s not great being exotic. Should Daniel M Davis get seriously ill, his chances of finding a transplant match are very bad. When he tells you that his wife is not one in a million but one in 100,000, you should feel good for her. Davis is one in four million, according to the genetic tests that the couple underwent. That’s very bad news, transplant-wise.

This all comes down to what Davis terms the “compatibility genes”. They are the set of genes that determine the make-up of your immune system and make you who you are.

We worry about where we came from. There is not a human civilisation on the planet that does not pay attention to its ancestors in some way. TV genealogy shows have probably amplified this trait, encouraging us to treasure our roots (or despair at them) in ever larger measure. So it’s no wonder we don’t cope well with the idea of organ transplantation: it messes with everything.

A study carried out in Sweden demonstrates the problem. In interviews with patients who had received someone else’s kidney, almost all of the subjects said that they felt it was best not to know too much about the donor. For some irrational, inexplicable reason, we are psychologically sideswiped by the idea that someone else’s meat has been installed inside our own. Some patients even worried about worrying about it, expressing a fear that too much “brooding” over the donor could lead their bodies to reject the foreign tissue.

We now know, thanks to a half-century of scientific sleuthing, that this isn’t true. Rejection of foreign bodies results from the activities of the compatibility genes. Davis’s enlightening book tells the extraordinary story of that discovery. As well as dealing with foreign tissue, the compatibility genes seem to influence our selection of biologically beneficial partners. It turns out that we look for complementary immune systems that enhance the chance of our offspring’s survival. Get it wrong at your peril: the compatibility genes are, it seems, frequently to blame in miscarriages. The contributions frommother and father have to be a good complementary pairing for a pregnancy to be successful. If Davis’s wife had chosen a more “common” man, she might have found herself with someone whose genes were too similar to her own, with adverse effects on the couple’s fertility. As Davis puts it, “Differences in our immune-system genes can influence who gets born.”

Sadly, science has not yet given us ways to cope with these differences. The best you can do is try to find a partner who somehow smells right. Evolution’s finest innovation might be the nose: we use it to check whether someone else’s immune system is complementary to our own.

Evolution is not perfect, however: given that as many as one in three pregnancies ends in miscarriage, cleary the smell is too subtle. Either that or we are all washing too thoroughly (or not doing enough investigative snogging).

It is almost ironic that the scientists who laid the foundations of this kind of research also had coupling issues. The Nobel laureate biologist Peter Medawar’s work elucidating what causes the rejection of transplants was so intense that he told his wife that she had claim on his love but not his time (and that he would be fine with an open marriage). The Danish biologist and sadomasochism fan Niels Jerne had a string of affairs before his wife (who had her share of lovers) committed suicide; it was only later, suppressing his grief with a gruelling work schedule, that Jerne uncovered the protective powers of antibodies. The Austrian Karl Landsteiner discovered the vital distinctions we know as blood groups. He also lived with his mother until she died. When he married shortly after that, the new Mrs Landsteiner faced the nightly distraction of her mother-in-law’s death mask on the bedroom wall. To her credit, the couple did manage to have a child.

Many more scientists are threaded through the pages of Davis’s thoughtful book and they all share one thing: the grinding heartbreak that is the slow progress of scientific discovery. It’s a heartbreak that Davis knows well; he is a leading figure in this subject. Though the science behind what causes our body to recognise itself and reject foreign material is more than 60 years old, he tells us, the conclusions we can draw from it are still fairly limited. Nonetheless, The Compatibility Gene is a fascinating, expertly told story of a field that may yield significant treasures in the decades to come.

Michael Brooks is the New Statesman’s science columnist 

The science behind our bodies' rejection of foreign material is 60 years old, Davis writes, but the conclusions we can draw are still limited. Photograph: Getty Images.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 02 September 2013 issue of the New Statesman, Syria: The west humiliated

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Why does food taste better when we Instagram it?

Delay leads to increased pleasure when you set up a perfect shot of your dinner.

Been on holiday? Take any snaps? Of course you did – but if you’re anything like me, your friends and family didn’t make it into many of them. Frankly, I can only hope that Mr Whippy and I will still be mates in sixty years, because I’m going to have an awful lot of pictures of him to look back on.

Once a decidedly niche pursuit, photographing food is now almost as popular as eating it, and if you thought that the habit was annoying at home, it is even worse when it intrudes on the sacred peace of a holiday. Buy an ice cream and you’ll find yourself alone with a cone as your companion rushes across a four-lane highway to capture his or hers against the azure sea. Reach for a chip before the bowl has been immortalised on social media and get your hand smacked for your trouble.

It’s a trend that sucks the joy out of every meal – unless, that is, you’re the one behind the camera. A new study published in the Journal of Personality and Social Psychology suggests that taking pictures of food enhances our pleasure in it. Diners at the food court of a farmers’ market in Philadelphia were asked either to photograph their meal or to eat “as you normally would”, then were questioned about how they found it. Those in the photography group reported that not only did they enjoy their meal more, but they were “significantly more immersed in the experience” of eating it.

This backs up evidence from previous studies, including one from this year in the Journal of Consumer Marketing, which found that participants who had been asked to photograph a red velvet cake – that bleeding behemoth of American overindulgence – later rated it as significantly tastier than those who had not.

Interestingly, taking a picture of a fruit salad had no effect on its perceived charms, but “when descriptive social norms regarding healthy eating [were] made salient”, photographing these healthier foods did lead to greater enjoyment. In other words, if you see lots of glossy, beautifully lit pictures of chia seed pudding on social media, you are more likely to believe that it’s edible, despite all the evidence to the contrary.
This may seem puzzling. After all, surely anything tastes better fresh from the kitchen rather than a protracted glamour shoot – runny yolks carefully split to capture that golden ooze, strips of bacon arranged just so atop plump hemispheres of avocado, pillowy burger buns posed to give a glimpse of meat beneath. It is hardly surprising that 95 million posts on Instagram, the photo-sharing site, proudly bear the hashtag #foodporn.

However, it is this delay that is apparently responsible for the increase in pleasure: the act of rearranging that parsley garnish, or moving the plate closer to the light, increases our anticipation of what we are about to eat, forcing us to consider how delicious it looks even as we forbid ourselves to take a bite until the perfect shot is in the bag. You could no doubt achieve the same heightened sense of satisfaction by saying grace before tucking in, but you would lose the gratification that comes from imagining other people ogling your grilled Ibizan sardines as they tuck in to an egg mayonnaise at their desk.

Bear in mind, though, that the food that is most successful on Instagram often has a freakish quality – lurid, rainbow-coloured bagel-croissant hybrids that look like something out of Frankenstein’s bakery are particularly popular at the moment – which may lead to some unwise menu choices in pursuit of online acclaim.

On the plus side, if a diet of giant burgers and salted-caramel lattes leaves you feeling queasy, take heart: if there is one thing that social media likes more than #avotoast, it is embarrassing oversharing. After a week of sickening ice-cream shots, a sickbed selfie is guaranteed to cheer up the rest of us. 

Felicity Cloake is the New Statesman’s food columnist. Her latest book is The A-Z of Eating: a Flavour Map for Adventurous Cooks.

This article first appeared in the 25 August 2016 issue of the New Statesman, Cameron: the legacy of a loser