Researchers at the University of Copenhagen compared the genomes of Bajau divers with a neighboring, non-diving population to find out whether their famous breath-holding ability had a genetic basis rather than just a lifetime of practice.
The team found strong natural selection in the Bajau on a gene called PDE10A, linked to a notably larger spleen, which acts as a reservoir of oxygen-carrying red blood cells that can be released into circulation during a dive. A second gene, BDKRB2, showed signs of selection tied to the body's automatic diving reflex.
A larger spleen gives divers a bigger pool of oxygenated blood to draw on when they hold their breath underwater, which may extend how long they can stay down. Ultrasound showed larger spleens even in Bajau who do not dive, pointing to an evolved trait, though dive times themselves were not tested against the genes.
Read the original study
Ilardo et al., Cell, 2018 · doi.org/10.1016/j.cell.2018.03.054
Generations of diving left its mark on the spleen.
Source
- Ilardo, M. A., Moltke, I., Korneliussen, T. S., Cheng, J., Stern, A. J., Racimo, F., de Barros Damgaard, P., Sikora, M., Seguin-Orlando, A., Rasmussen, S., van den Munckhof, I. C. L., Ter Horst, R., Joosten, L. A. B., Netea, M. G., Salingkat, S., Nielsen, R., & Willerslev, E. (2018). Physiological and Genetic Adaptations to Diving in Sea Nomads. Cell, 173(3), 569–580.e15. https://doi.org/10.1016/j.cell.2018.03.054