Stripping Down Science (2 page)

Five chemicals were found in the orchid scent that produced a positive response, which were benzyl alcohol, benzyl acetate, octadecan-1-ol, eicosan-1-ol and 11-eicosen-1-ol. This latter molecule made the researchers sit up like they'd been stung – because it's used by bees as an alarm pheromone and is highly attractive to foraging workers.

Hornets, it seems, have learned to home in on this smell in order to capture bees, which they can then feed to their young. But occasionally, fooled by the irresistible odour of a ready meal, they grab an orchid instead, pollinating it in the process!

The vitamins, minerals and health-supplements market is now a multibillion-dollar international industry. What we're all buying into every time we take a packet of horse-sized pills off the shelf is the idea that the contents will make us healthier, less likely to catch something and hopefully live longer. It's a bit like a cross between a chemical comfort blanket and an insurance policy – the contents absolve the user of having to worry about doing other boring ‘good for you' things, like eating properly, taking regular exercise or not drinking too much.

But the health hype hides a metabolic myth on a massive scale: vitamin tablets don't make you live any longer and they might even shorten your life. At least that's the conclusion of Goran Bjelakovic and his colleagues at the University of Copenhagen,
³
where they've carried out the
largest analysis yet on the pill-popping effects of vitamin supplements.

What the Copenhagen team have done is a meta-analysis. This is a process by which researchers combine the results of many (in this case 67) smaller trials to achieve what is effectively one very large dataset of participants. Doing this makes a study much more powerful, so researchers can iron out bias and spot more subtle trends that might previously have been masked by statistical ‘noise' in a smaller study. When Bjelakovic did this, the summed results from over 230,000 people, which included both healthy individuals and people with a variety of ailments, showed that taking antioxidant vitamins such as vitamin A, beta-carotene, vitamin E, vitamin C and selenium, was no better at cutting mortality rates than taking a placebo. The vitamins were, however, much better at emptying patients' wallets.

The bad news for the ‘nutraceuticals' industry didn't stop there. When the team focused on 46 trials that were judged to be the most reliable, they found evidence that some of these vitamins may actually be significantly increasing mortality rates. Vitamin A, for instance, was linked to a 16% increase in deaths, and vitamin E to a
4% increase. However, the use of antioxidant vitamins in staving off disease and the effects of ageing is actually based on sound science. Reactive products of metabolism, such as free radicals, are known to damage cells and DNA, and antioxidants can act as a shield, soaking up the radicals before they can pounce destructively on a gene or a cell membrane. But taking excess quantities of these chemicals clearly doesn't work, presumably because there are other knock-on metabolic effects that undo any benefits. In some respects it's a bit like over-filling your car engine with oil and expecting it to run better.

There's no quick fix. The bottom line is that the human body has evolved to absorb and use these micronutrients in the context and concentrations in which they are found in a normal diet, not a packet of pills. The best solution is to do what the nutritionists have been telling us for decades and what public health doctors have recently confirmed in large-scale trials: take regular exercise, drink in moderation, don't smoke and above all, eat five portions per day of fruit and vegetables.

Makes me feel ill just thinking about it … maybe I need a supplement.

FACT BOX

Ways to live longer that
are
evidence-based

For those seeking to live longer without risking life, limb and bank balance into the bargain, scientists at Cambridge University have identified four simple things that could gain you an extra 14 years. Between 1994 and 1997, epidemiologist Professor Kay-Tee Khaw and her colleagues
⁴
recruited 20,000 men and women aged between 45 and 71 years into a study to look at the impact of various lifestyle factors on longevity and health.

At the time of enrolment, the study subjects filled in a simple questionnaire about their lifestyles and were also assessed by nurses at a clinic. They earned a point for every positive answer to being a non-smoker, a light drinker and regular exerciser. They also earned a point if a blood test revealed a vitamin C level consistent with eating about five daily
portions of fruit and vegetables.

The team then followed up the volunteers until 2006, tallying up who lived and died. The results showed that, over an average period of 11 years, people who had scored zero points at the initial assessment were four times more likely to have died than participants who had scored four points. They also found that people scoring zero had about the same risk of dying at any time as someone 14 years older than them who had a score of four points.

The moral of this story is quit smoking, drink in moderation, take the stairs not the lift and follow the five-a-day plan (that's portions of fruit and vegetables, not pints or hamburgers) and you might live 14 years longer!

A little while back, a South Korean company, RNL Bio, opened its doors offering a commercial canine-cloning service.
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Their first order, with a price tag of $150,000, was to re-create ‘Booger', who had died 18 months earlier. He was a pit bull terrier previously owned by a Californian woman who presumably missed him so much she wanted him back again.

You can understand her sentiments. Most of us have mourned the passing of a pet at some time in our lives, but now some seem to be prepared to go as far as cloning their dead dogs, despite the enormous cost, in the belief that they can turn them into the canine equivalent of Lazarus. Unfortunately, the misconception under which most of these people are labouring is the belief that not only will they get back a pet that looks like the one they lost, but it will also have the same lovable
personality traits, temperament and training.

This is just not true. It's like assuming that a newborn baby would know how to talk because its mother and father could. Similarly, you wouldn't expect a newborn dog to know how to herd sheep because its father was a collie! Although some aspects of behaviour are driven by genes, the majority is learned, so it's wrong to assume that if you clone your dead dog you'll get anything other than a totally new pet that merely looks like your old one. The best evidence to prove this point is to look at identical twins, which are natural clones formed when a developing embryo splits in two. Although they're very difficult to tell apart physically, anyone who is a twin or knows a pair very well will tell you that they certainly have their own unique preferences, likes and dislikes.

The reason for this is that humans' and animals' brains are moulded and shaped by their day-to-day experiences. As the Oxford University neuroscientist and author Susan Greenfield put it to me, ‘the brain you go to bed with is not the same brain you woke up with this morning'. So if two clones, dog or human, have different experiences in life, they will be two totally different individuals.

And since it would be almost impossible to ensure that a cloned pet is raised in an identical environment and have the same experiences as its predecessor, it's almost certain that the two animals would be different. The nail was driven further into this coffin recently when scientists showed that random chance also plays a major role in the way some parts of the nervous system wire themselves together. Even if the environment and upbringing were the same, the likelihood is that the resulting brain wouldn't be.

But for pet-parents who are so far undecided about whether to bring their dog back from the dead, there is another option. US company ViaGen run a ‘preserving your pets' service.
⁶
For
$1500 and a $150 annual retention fee, they'll store your pets' genes for you so you can clone them later if you like. Even if they choose not to, owners can sleep easy in the knowledge that they've kept their pets' genetic legacy alive, even after the pooch has passed on.

FACT BOX

Genes that control canine coiffures

Dog owners unsatisfied with the concept of merely cloning a canine, preferring instead the prospect of some additional genetic manipulation, will be heartened to know that scientists have recently tracked down the genes that give dogs their hairstyles.

The discovery was made by National Institutes of Health (NIH) researcher Edouard Cadieu and his colleagues in the United States,
⁷
who successfully sniffed out three crucial genes that control whether a dog has hair that is long or short, wiry or curly, or
comes with ‘furnishings' – the moustache and eyebrows seen in some breeds.

Cadieu and his colleagues made the discovery using a technique called genome-wide association. By comparing the pattern of genetic markers called SNPs (single nucleotide polymorphisms) from many dogs with a single characteristic of interest alongside other dog breeds lacking that trait, the team were able to home in on the genetic region and then the genes underlying the different hairstyles.

Samples from more than 1000 dogs from 80 different breeds led the researchers initially to a gene called RSPO2 (R-spondin-2), which gives certain breeds of dogs their eyebrows. Next, they flushed out a gene called FGF5, which comes in two forms, one of which (the T form) leads to long hair when two copies of it are present, and a G form that triggers a short back and sides. Finally, the scientists were able to track down the gene for curly hair, KRT71, which encodes the protein keratin, used to make the hair itself (and claws). This also comes in two forms, T and C, with curly
coated pooches carrying two copies of the T form. Overall, the scientists were surprised to see that the three genes they'd identified accounted for more than 95% of the hairstyles seen in all of the animals analysed.

Also quite surprising was the finding that when the researchers studied the genetic sequences of three grey wolves, none of the alternative hairstyle genes seen amongst the dogs were present in these near relatives. The wolf genes were for short, straight hair and no ‘furnishings', suggesting they are a ‘wild-type' genetic stock from which modern dogs derive originally.

The difference between a dog and a wolf amounts to about 15,000 years of selective breeding by humans. The fact that just three genes account for the coat differences across such a broad range of dog breeds shows that, in each case, single mutations have produced each coat trait and have subsequently been bred by us into all of the other dogs around today.