Genetics versus epigenetics
Is our lifespan written in our DNA or does it depend on our behavior? Modern science leans in favor of the second explanation. The question is not new. Aristotle, while studying chicken embryos in 350 B.C., wondered if we were pre-programmed or shaped by our environment, a debate as scientific as it is philosophical!
The 20th century made genetics sacrosanct, with the compelling idea that we are governed by our genes. Our genes make us blond or brunette, tall or short, susceptible or not to hereditary disorders. Going one step further, our life expectancy would thus be inscribed in our genome.
“Genetics is no longer all-powerful! For 50 years, we were told that the genetic code we inherited from our parents would determine our future health. Today that’s considered about 80% wrong, and it’s proven by a science called epigenetics: ‘epi’ means ‘upon’ in Greek,” explains Professor Gilbert Deray, a nephrologist and pharmacologist at La Pitié-Salpêtrière Hospital in Paris.
Controlling one’s genetic future
Is epigenetics really “above the genes”? Can it go against the laws of hereditary?
Several studies have shown that it can modify all the machinery of our cells, since the activity of our genes is impacted by our behavior.
“Your genetic code is made up of about 23,000 genes, bits of chromosomes like software. You decide whether to activate or disactivate each one of these little genes. Imagine that you have a gene that codes for lung cancer: by adopting certain behaviors – especially by not smoking – you’ll disactivate this gene. It will no longer be expressed. You control about 80% of your genetic activity and, therefore, your genetic future,” says Professor Deray.
However, in 20% of cases, genetics still has the upper hand :
The evidence can be found in inherited diseases, with DNA codes that do not function properly. Even with the progress made by gene therapy, these diseases remain untreatable. Nonetheless, in the vast majority of cases we can act to change things.
“A number of pharmaceutical companies are working to discover drugs that transform the action of certain genes, and it is very likely that in the next 10 years they will succeed. But for now, we can control our lifestyle, which has an incredible influence on our genetic code. If we adopt the right lifestyle, we will modify our epigenetic activity and our future health,” explains Professor Deray.