Why are sea nomads "Bajau tribe" able to work underwater for a long time?

The Bajau tribe, known as a nomadic ocean, is a minority living in Indonesia, the southern part of the Philippines, Malaysia, living with a residence at sea, not land. The Bajau tribe has a phenomenal physical ability such as reaching water depth of 80 meters with elemental diving and acting for 3 minutes or more in the water. According to Mr. Melissa Irald et al. At the University of Copenhagen, it turned out that the secret of the incredible physical ability of the Bajau is in the spleen (elephant).

Physiological and Genetic Adaptations to Diving in Sea Nomads: Cell
https://www.cell.com/cell/abstract/S0092-8674(18)30386-6

These 'sea nomads' are the first known humans to have a genetic adaptation to diving
https://www.sciencealert.com/indonesian-bajau-genetic-changes-adapt-them-to-aquatic-lifestyle

The Bajau tribe mainly lives in fishery by fishing, and when fishing, use only the minimum tools such as wooden goggles and Mori. Because of this, the Bajau tribe had to undercut for a long time with imagination and it is thought that the ability to stop breathing has developed.

Research teams of Mr. Iralard et al. Investigated the people of the Bajau, revealed that the people of the Bajau have 1.6 times larger spleen than the inhabitants of the adjacent village (Saluan). Also, people who normally do not fish among the Bajau tribes also have large spleens, so it is considered that individuals are genetically changed, not to change to apply to the environment.

The reason why the Bajau spleen is big is that it is greatly related to the role of "saving the blood" of the spleen. While stopping breathing, such as during diving, the human body attempts to reduce the blood flow by contracting the blood vessels of the limbs and to maintain oxygen in the blood. At this time, the spleen contracts and also plays a role of delivering oxygen to the blood vessel. Having a large spleen therefore increases the amount of oxygen delivered and it makes it possible to stop breathing for a long time.


When the research team investigated the DNA of the Bajau family, it turned out that there was a mutation in the gene called "PDE10A". The PDE 10A is "T4 (ThyroxineThere is a function to control the thyroid hormone called "). In mouse experiments, we know that there is a relationship between T4 secretion level and spleen size.

According to Mr. Irald, "Understanding the mechanism of the genetic application of the Bajau tribe will be useful in the treatment of hypoxia that can not incorporate enough oxygen due to disease or injury."