2023-12-01 14:40:56
Raise your hand if you haven’t tried to improve your endurance without breathing underwater. The seabed is a hiding place that, due to its difficulty, is a paradise for many. On average, human beings can submerge unaided for less than a minute, and freediving swimmers can improve those marks with a lot of training. However, there is a tribe that manages to descend up to 70 meters deep and stay underwater for up to 13 minutes.
These are the Bajau, also known as the ‘sea nomads’. For hundreds of years they resided on floating platforms in Indonesia or Malaysia and fed on the fish they obtained by diving with their lungs. But how is it possible to spend 13 minutes without breathing underwater?
The answer to this question was pointed out by researcher Melissa Llardo, from the Center for Geogenetics of the University of Copenhagen in 2018. Her observations were published in the journal Cell and in them she provided the first evidence that the secret of the Bajau was in a mutation of DNA that gave them larger spleens.
After taking several samples, Llardo verified that the average size of the spleen of a Bajau was 50% larger than those of its neighbors in Saluan.
When a person submerges and gains depth, the increase in pressure causes the blood vessels in the lungs to fill with more blood. This is dangerous as the vessels can rupture and cause death. After DNA analysis, the researchers found a gene known as PDE10A, which is not present in the residents of Saluan, and which is responsible for regulating the secretion of the thyroid hormone T4. They observed that this gene was the magic key to being able to dive for so long and so deep.
“Our results suggest that the Bajau have experienced unique adaptations associated with spleen size and their diving experiences, thus adding a new example to the list of fascinating genetic adaptations that humans have experienced in recent evolutionary history” explains in the study.
These findings may help understand acute hypoxia, a condition in which body tissues experience rapid loss of oxygen caused by chronic lung disease, heart failure, anemia, or carbon monoxide poisoning.
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