Is being funny in your genes? Comedian Nik Rabinowitz takes a DNA test

Nik Rabinowitz is no caveman and he has the genetic results to prove it. The results of a panel of DNA tests show that he would not thrive on the Palaeolithic diet of the ancient huntsmen (all meat and no bread).

The fact that he orders tempura broccoli when we meet in a Cape Town coffee shop could tell us this, but it's always good to have scientific evidence.

"I'm a 12th generation suburban Woolworths Jew, not a caveman," says the comedian, whose DNA states that his wiry body leans towards "everything in moderation".

"As much as I love Tim Noakes, I never have to go on his diet."

Rabinowitz shared all his DNA secrets with the Sunday Times after the genetic testing company, Geneway, tested his saliva for this story on the benefits and pitfalls of getting more information about your future health or sickness and death.

It's far more precise than gazing into a crystal ball and a number of results are based on solid scientific studies, whereas others are more observational or speculative.

In SA, commercial companies offer people the chance to find out more about their genes and how they interact and impact on diet, sport, skin, wellness and medication.

Geneway operations manager Christa North, who is based in Johannesburg, says: "Every single test we do has four controls and the results are accurate. All the information we give you is based on published studies and referenced."

A medical scientist signs off on them, like a pathologist would do for bloods, and trained practitioners interpret the reports for clients like Rabinowitz.

"Personalised medicine is about empowerment and we want people to know what steps they need to take," says North.

Rabinowitz's gene variations ranged from great - his razor wit is likely to stay intact given that he got green for cognitive function and is not susceptive to addiction (besides his cellphone) - to more disquieting results.

His cholesterol and blood-clotting genes came out red. However, this wasn't a shock to Rabinowitz, whose family has a history of heart disease.

"My father's father had a heart attack at 50 and my dad at 40. He lived to 88 after having a triple bypass in his 60s. When I turned 40 I was put on medication," he says.

These results confirmed what he already knew, but others were unexpected. For example, he is missing a gene related to hormone function.

Another gene variation concerned the "motherf***ing" (TMTHFR A1298C) in his words, which is tied to fatigue, chronic pain, IBS and mood-related problems.

His sports summary says that genetically his "post-exercise recovery rate is compromised".

"I must stop training so hard," says Rabinowitz (who trains twice a week for half an hour).

"My DNA shows I'm more of an endurance athlete so I'm never going to be a cross-fitter," adds Rabinowitz, who surfs whenever he can.

He hopes to turn other results, like his "night owl" circadian rhythm, to his advantage at home.

"I will tell my wife and kids that my DNA results say I must sleep in."

North points out that people can retrain and force their bodies into a rhythm, but naturally they have a cycle of optimal performance.

"With professional athletes, we discuss their results only with the doctors and the players, never the coaches," she says.

When Rabinowitz is forced out of bed (which he is by young kids), he shouldn't rely on a double espresso to get moving because his genes warn that he metabolises toxins, like coffee, slowly. "Does this explain why I get the shakes?" he asks.

North says: "People's genetic variations influence their caffeine sensitivity and toxicity, whether they can have six cups a day or one at Christmas."

Stress is another red flag that stands out on Rabinowitz's wellness report.

"My ability to break down cortisol is not good. I should have a job as a massage therapist or a librarian," he says.

Yet Rabinowitz, whose show, Dry White, played in February, admits that he doesn't feel too stressed on stage.

"I used to prepare at the last minute. This time I prepared nine months in advance during Cape Town's worst drought, and then (unfortunately for him) it started to rain."

Luckily he doesn't use alcohol to get into the flow because his gene mutations indicate that "his detoxification in the liver is impaired" and he has a greater risk of diseases associated with regular drinking.

He's also apparently got impaired genes when it comes to converting "food into energy". This is not in fact a crisis because genes interact with each other in a pathway, not in isolation.

North says: "We usually compare them to a rugby team, where players work together to win a match but everyone has their own job and one doesn't cancel another out."

A more cryptic result concerns TBDNF (Val66Met) related to mood disorders and memory, where he's not exactly in the range of the commoners - the most common variation of the genes. Then again, many people are not.

"Everybody should have access to this kind of information," says Rabinowitz, observing that the results are way more specific than when he had a DNA test years ago.

A new study of DNA, from half a million people, found that 12 areas of the human genome significantly impacted on lifespan and people's genetic data could indicate if they would live longer than average.

"What's behind DNA testing, I suppose, is our quest for immortality and how to extend the quality of life with a set of imperfect genes. But pretty soon, when they edit out our gene errors, humans will be living to 150 or 200 years. Maybe my knock knees can be fixed for my descendants," says Rabinowitz.

HOW DNA TESTING WORKS

Gene variations revealed in DNA tests provide information about our susceptibility to certain conditions and diseases.

Commercial companies offer individuals genetic testing, focusing on genes which interact at a biochemical level with diet and lifestyle. They do not typically include genes like BRCA1, in which a faulty copy increases the risk of breast and ovarian cancer.

University of Cape Town genetic counsellor Tina-Marié Wessels says: "People should understand that there is a clear distinction between genetic testing that is useful clinically - where genetic variants cause disease - and variants which, in combination with other factors [like lifestyle], could lead to increased risk of disease."

Everyone has two copies of each gene, one inherited from the father and one from the mother.

Less than 1% of genes are slightly different between people, and this contributes to people's unique make-up.

North says: "You can get one of three results: both genes work, one is not working, or both are not working (flagged as red on their reports).

"We drop your DNA onto templates which are predesigned overseas. The results will match the good variations, the bad ones or the middle ones."

For example, Alzheimer's is associated with the gene variant APOE-e4. The risk is reduced if you have the rare E2 and E3 variant. (Rabinowitz has the winning combination of E2/E3). Double E4 variants suggest increased susceptibility.

Ethical concerns arise around DNA testing, and the US department of health's National Institutes of Health, for instance, doesn't recommend testing APOE status except for clinical drug research. Results could be used to discriminate against individuals by insurers and employers.

"We are aware that people are using information to make significant decisions," says North, who is excited about the pharmaceutical panels they introduced last year to test responsiveness to medication.

Initially, most of this research was done in oncology and psychiatry, however, pharmacogenetics now also covers heart disease, antibiotics, anaesthetics, pain, antihistamines and other fields.

Yael Joffe, the founder of genetic testing company 3X4, says: "Genetic testing is not a silver bullet, but it adds another layer of insight and information onto the physical examination, medical history, diet, blood markers and psychosocial history.

"We have three to four million places in our DNA where we are different from each other. This determines our responsiveness to diet, environment, stress and drugs. By knowing this we can help our clients to make better choices at every point in the day."

Joffe got into the field of genetic testing in London nearly 20 years ago.

"The first 10 years of my career people thought I was a quack and working in science fiction, but now it is mainstream," she says.

"We have another tool to make more efficient clinical decisions for patients. Testing is going through the roof. It has doubled year on year for the last five years."

Joffe shifted early in her career from dietetics to nutrigenomics.

"[On diet] we have followed a process of trial and error about what's best for us, and there has been so much error," she says.

Ten years ago, DNA testing would have cost millions of dollars. Now it is an option for many people, costing roughly R3,500 a person in SA.

IS THERE A ROAD RAGE GENE? 

People who don’t control their aggressive impulses could have the “roadrage” gene, according to Geneway genetic expert Christa North.

“This gene helps keep the neurotransmitters dopamine and serotonin in balance,” she said.

Without this balance, people tend to be less controlled in and after a stressful event.

“On a rugby field this could work. You don’t want a wuss,” she said. “But a couple of years ago a guy killed somebody and got some time off his sentence because of this gene.”

Paternal and maternal DNA tests may reveal surprising, and even contradictory, results about our ethnic makeup.

A US science writer got four different profiles from his DNA, because results were based on the databases of the four sources.

One of them, National Geographic, has a strong collection of about 850,000 samples through its Genographic Project.

Y chromosome testing gives insights into male ancestry whereas maternal testing (mitochondrial DNA) can give clues for both genders.

The Origins Centre at Wits University is one of the places to go for this.