It is proof that humans continue to evolve. The track is on the central Sulawesi peninsula in Indonesia. The life of its inhabitants, the Bajau tribe, is closely linked to fishing and wetlands. They capture most of their prey there. They can spend more time underwater than on the surface. Up to 60% of the daily work day. The tribe that dives like fish evolves to this day.
To go into the depths, they weigh themselves down with stones. They descend more than 60 meters. The most amazing thing is his ability to hold his breath. They last more than 10 minutes before rising to the surface again. Researchers want to unravel the genetic secrets to maintaining apnea for notable periods.
United to water
The Bajau have an intimate connection with the aquatic environment. They adapted to the limited access to oxygen during long periods of diving. Researcher Melissa Ilardo, from the University of Copenhagen, studied them in detail.
The spleen is an organ that is part of the lymphatic system. It plays a vital role in the body’s response to prolonged diving. During immersion, mammals exhibit the so-called dive reflex. This slows the heart rate, constricts blood vessels in the extremities and constricts the spleen.
This contraction of the spleen releases red blood cells into the bloodstream and increases the oxygen content in the blood. It turns out that, in the Bajau, the spleen is approximately 50% larger than usual. The exceptional physiological adaptation of the Bajau is revealed through genetic findings. Their genes are conditioned to favor apnea activity.
Adapting
For example, the inhabitants of the tribe that dive like fish have developed a receptor for bradykinin, a peptide associated with vasodilation. It is related to the diving reflex. These findings support the notion that hypoxia tolerance in the Bajau has a genetic basis.
Adaptation to the freediving lifestyle has shaped the expression of these genes. It provides a unique opportunity to study human adaptation to hypoxia tolerance. The influence of mutations associated with Bajau genes contributes to their remarkable underwater abilities. And it gives us a valuable perspective to understand how human evolution acts in extreme environments.
