Which is it? I mean 
is there one?
The best gene ever!
You know those people who drink, smoke, eat crap, never exercise and live healthily until 98 when a bus hits them and that’s how they die? That gene! What these people have.
Jokingly, there’s something called the “Churchill gene”, after Britain’s Prime Minister, Winston Churchill, which is said to enable a person to perform their best work whilst consuming amounts of alcohol that would otherwise kill people without the gene. Many artists who have diets consisting of exclusively booze and cigarettes have the Churchill gene. I don’t, that’s for sure. Not an artist, by any stretch of the imagination, nor am I able to metabolise booze with enviable speed or endurance I am but a mere mortal, without the best gene ever.