'Wanderlust gene' explains why some of us have the travel bug

My dad was 18 when he first set off to explore the world on his own. And even then, he'd already seen a fair portion of it. He'd lived with his parents in Hong Kong and Singapore. He'd been to school in Australia and in Scotland.

But when he was 18 he took the biggest leap of faith: he signed up to work as an apprentice in the merchant navy. He took a two-year contract with a shipping company. He walked up the gangplank of a ship he'd never boarded before, to do a job he'd never performed, with a bunch of people he'd never met, to see a world he'd never experienced, knowing he wouldn't return home for two years at the least. In fact, he didn't make it back for four.

My mum, meanwhile, says she never had much interest in travel. That is, until she decided, at the age of 19, to leave her home in England, to jump on board a ship and sail to the Bahamas. She'd find work when she arrived, she figured. She'd sort something out.

She says she never had much interest in travel, but that move is the sort you would only make with the heart of an adventurer, particularly back then when you couldn't just jump on a plane and fly home if things went wrong. She stayed in the Bahamas for a few years before moving to Australia, where she eventually got a job on a cruise ship in order to see more of the world.

My parents still travel, constantly. They're both wanderers, both explorers. Dad has visited pretty much every country with a coastline. Mum still hikes up mountains. She went sky-diving when she was in her 60s. They've both been to Antarctica. They've camped in Utah. They've hung out in Buenos Aires.

I mention all of this by way of explanation. See, I don't remember getting the "travel bug", as some travellers do. I can't pinpoint a particular moment when I realised that I loved travel, that it was all I ever wanted to do. I've just always known. I've always wanted to do it.

And that's because of my parents. Not just because of the way they brought me up, or the experiences they gave me, but possibly, in an even larger way, because of their genes, because of a special genetic variation that they most likely possess, and that they most likely passed on to me.

It's called the "wanderlust gene". They probably have it. I probably have it. You might have it too.

Scientists have discovered a genetic variation called DRD4-7R, which occurs in about 20 per cent of the human population. This variation affects dopamine levels in the brain – and dopamine isn't just a chemical that makes you feel good, as is commonly understood. It also makes you more curious, more obsessed with finding things that are new and interesting and exciting, more likely to take risks in the pursuit of pleasure.