The ocean changed their DNA: Discover the incredible adaptation of the Bajau people

A genetic mutation that greatly benefits them

A recent study indicates that genetic adaptations possibly enhancing diving abilities have been found in a nomadic group from Southeast Asia.

The Bajau: a people of the waters

Unlike most humans, the Bajau live in the waters of the sea and spend 60% of their time submerged. They are so familiar with this element that in 2004, they were able to warn tourists of imminent danger, protecting them from the tsunami which ravaged the coasts.

Science and genetic evolution of the Bajau

This lifestyle has aroused the interest of researchers at the Center for GeoGenetics at the University of Copenhagen in Denmark. Melissa Llardo, lead author of the study, went to where the Bajau live to get to know them and study them.

The Bajau dive in search of fish

These nomadic people live in the waters of the Philippines, Malaysia and Indonesia. The Bajau dive to catch fish, but also elements from the seabed, which they use to make handicrafts.

Little time on dry land

Melissa Llardo explained to the BBC's Inside Science that "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.”

The Bajau and their ability to hold their breath

For this reason, the Bajau have developed an extraordinary diving ability and can spend 13 minutes submerged at depths of up to 60 meters, explains National Geographic.

The spleen

With such ingenuity, the researcher suspected the Bajau of having a biological advantage and decided to study one organ in particular: the spleen.

Why study the spleen?

The spleen controls, stores and destroys blood cells. About the size of a fist, it is located in the abdominal cavity, just below the lungs. When we dive, it functions like a biological scuba tank, increasing the availability of oxygen, according to the BBC.

The spleen of marine mammals

Another factor that suggests spleen size may be linked to diving ability is marine mammals, such as seals, with proportionately larger spleens.

Visit to Indonesia

The author of the study, Dr Ilardo used a portable ultrasound machine to study the Bajau, "I asked very nicely for the people to let me look at their spleens," she said.

The Bajau spleen is bigger

After measuring this important organ, the researchers found that it was 50 percent larger among the Bajau than among their agricultural neighbors, the Saluans, who live on dry land and only enter the water occasionally.

Spleens of similar dimensions

The researchers also observed that Bajau individuals who had other activities, and therefore did not dive, had spleens the same size as their family members.

A genetic evolution

Thus, according to the study, published in the scientific journal Cell, everything indicates that the increase in the size of the spleen is potentially a genetic evolution, and not a momentary adaptation of the organ.

When did this development occur?

However, Ilardo cautioned: ""It's not clear how long the Bajau have had this lifestyle, or when exactly the adaptation arose give the genetic data that we have now."

The Bajau population

According to rough estimates, Southeast Asia has around one million Bajau people. Unfortunately, their way of life is under threat.

On the margins of society

According to National Geographic, the Bajau do not have the same rights as other citizens and live on the margins of society.

The fishing industry is a threat

Furthermore, the increase in industrial fishing is seriously harming their main livelihood, hand fishing.

Why study the spleen in this population?

The scientific interest in understanding how this evolution occurred and how the Bajau organism functions also has a medical purpose.

Acute hypoxia

As National Geographic explains, the diving reflex is similar to a condition called acute hypoxia, in which humans quickly lose oxygen. In some cases, this condition results in death. The study of the Bajau spleen could therefore serve as a laboratory for understanding hypoxia.