For the first time, a scientific study shows that the human body adapts genetically to diving. This is particularly the case with the Bajau, a group of indigenous Indonesians whose spleen is larger. Explanations.
There is a connection between the size of the spleen and the ability to dive. This is shown by a study carried out in connection with the Bajau people, also called the “nomads of the sea” and published in the journal Cell. These indigenous people, who live in Indonesia, have naturally larger spleens, which allow them to dive to greater depths. The Bajau people are a people of fishermen, who for over a thousand years traveled the seas of Southeast Asia by boat. The “nomads of the sea” feed mainly by diving with spears.
Today installed on Indonesian islands, they are still able to dive in deep water equipped with weights and a pair of glasses. Based on this information, Melissa Ilardo, the study’s lead author, wondered if the Bajau did not have spleen genetically adapted to diving.
What is the role of the spleen?
The researcher was inspired by deep-diving seals, in particular the Weddell seal, which has a disproportionate spleen.
The spleen is part of what is called the “immersion reflex”. When our body is submerged in cold water, this reflex is triggered to help it survive in an oxygen-free environment. Our heart rate slows down and our spleen contracts. When this contracts, it causes a surge of oxygen and thus prolongs the diving time. Melissa Ilardo took genetic samples from the Bajau and their neighbors, the Saluans.
50% larger spleen
The results were conclusive: the Bajau have indeed a median spleen size 50% larger than that of the Saluan. On the other hand, even those who do not dive have a larger spleen. Particularly because the members of this people have one more gene: PDE10A. The researchers believe that this gene controls and increases the thyroid hormone T4, which in turn increases the size of the spleen. This is the first time that the genetic adaptation to diving has been followed in humans.
A new issue of Cell is out @ https://t.co/ye9kiMN3jk – feat. #sea #nomads, #CRISPR & #tau, #phaseseparation & #FUS, #immunotherapy & MORE! pic.twitter.com/R97v8MTTMm
– Cell at CellPress (@CellCellPress) April 19, 2018
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