Asian tribe's 'new mutant gene' to swim underwater for five hours a day - the science backs it up
Living in homes constructed on stilts in the open waters near Indonesia, Malaysia and the Philippines are the Bajau people, a tribe who live their lives predominantly on water.
Numbering around 1.2 million worldwide, the Bajau spend their days diving, spearfishing and collecting shellfish to sustain their lifestyle, often being referred to by their neighbours as 'sea nomads'.
And it's maintaining this lifestyle for over 1,000 years that has allowed the Bajau to develop genetic mutations that allow their bodies to be better suited to the sea.
The average person is able to hold their breath underwater for around 30 to 60 seconds before needing to take a breath, with some people able to train themselves to last a couple of minutes.
Advert
However for the Bajau, this number is a lot higher, with people from this South-East Asian group able to stay underwater for up to 10 minutes at a time, allowing them to freedive to depths the rest of us could only dream of. So how do they do it?
Mutated genes and enlarged spleens
Naturally, there has been a great deal of interest in understanding how the Bajau people have been able to adapt, with the recent study revealing the enhanced underwater breathing is down to two things: enlarged spleens and a genetic mutation.
Spleens might not be the organ you usually think of as detrimental to your wellbeing, but it’s actually essential for providing you with more oxygen in your blood - so a bigger spleen is perfect when diving for 8 hours a day.
First author of the study, Melissa Ilardo, from the University of Copenhagen, told the BBC's Inside Science programme: "For possibly thousands of years, [they] have been living on house boats, travelling from place to place in the waters of South-East Asia and visiting land only occasionally. So everything they need, they get from the sea.
"When they're diving in the traditional way, they dive repeatedly for about eight hours a day, spending about 60 percent of their time underwater. So this could be anything from 30 seconds to several minutes, but they're diving to depths of over 70m.”
Using traditional wooden goggles and weighted belts, the tribe has learned to adapt to their aquatic lifestyle.
"There's a human dive response that's triggered by holding your breath and submerging yourself in water. You can trigger it by submerging your face in cold water," Ilardo explained.
"Your heart rate slows down, you have peripheral vasoconstriction where the blood vessels in your extremities get smaller to preserve the oxygenated blood for your vital organs and then the last thing is a contraction of the spleen.
"The spleen is a reservoir for oxygenated red blood cells, so when it contracts, it gives you an oxygen boost. It's like a biological scuba tank."
That’s when Ilardo decided to take a look for herself and asked villagers to look at their spleens.
What she found was that the Bajau people had a 50% larger spleen then a neighbouring village.
Co-author Prof Rasmus Nielsen, from the University of California, Berkeley said: "We could ask the question: are there any genetic variants - are there any mutations - that are at a much higher frequency, that have changed their frequency specifically in the Bajau compared to other populations.”
After further tests, they found that the gene, PDE10A, was found to correlate with the Bajau's larger spleen size.
The gene is typically known for regulating a thyroid hormone in mice which also controls the size of the spleen.
In a separate study of Tibetan people living in high altitudes, they found that their gene adaptation came from inbreeding with Neanderthals and the researchers wonder if this is also a possibility here.
Rasmus Nielsen added: "It's a wonderful example of how humans can adapt to their local environments, but there may be some medical interest in this. There's been a lot of interest in understanding hypoxia adaptations - adaptations to low oxygen levels.
"By studying the Bajau, we can figure out: what are some of the genes that help predict differences in people in how they respond to acute low oxygen levels?"
But it could soon be over for the people.
Santarawi Lalisan, an elder statesman of the tribe told Giuseppe from Project Happiness that their culture is now dying due to Western ways.
He said: "A lot of plastic has arrived here because today the Badjao go to the supermarket and here they use plastic and no longer paper. In the past, the Badjao only used paper when they were buying something."
Now, the sea is full of plastic and is making it difficult for the tribe to continue their ways.
Topics: Environment, Health, Science, Travel
Britt Jones