Small changes in our genes help give us our unique traits. Scientists have found that one genetic variation carried by the Bajau, people of Southeast Asia, has probably allowed them to hunt underwater for lengthy stretches of time. Over 1,000 years and many generations, these folks have spent a lot of time holding their breath as they free dive to collect fish and shellfish.
"This is a fascinating example of how humans can, in a relatively short amount of time, adapt to a local environment," said researcher Rasmus Nielsen of the University of California, Berkeley.
The body has several ways to get by in an environment that is low in oxygen. Simply increasing lung capacity is one way, another is to increase the production of red blood cells, so more oxygen moves to the body. Another, described by the scientists in this work, is to increase the size of the spleen, where red blood cells carrying oxygen are stored. If a person is diving, the spleen can contract and released those stored cells and their oxygen into circulation.