Genetic research reveals that humans have undergone significant biological adaptations in recent evolutionary history, challenging common assumptions. This understanding provides insights into human resilience and adaptability, benefiting fields like medicine and public health.
Indigenous communities in the Bolivian highlands have adapted to living at altitudes over two miles high, where oxygen levels are significantly lower. Scientists have discovered that these Andean populations have also developed remarkable genetic adaptations since settling in the South American highlands around 10,000 years ago. These adaptations help them thrive in their challenging environment.
High levels of arsenic, a toxic substance linked to various health problems, are naturally present in the drinking water of the Andes. However, the biochemistry of Andean people has evolved to efficiently metabolize this poison. Populations in Bolivia, Argentina, and Chile have developed variants in the AS3MT gene. This gene produces an enzyme that breaks down arsenic in the liver.
This is a prime example of natural selection, where organisms evolve to adapt to their environment for survival and reproduction. Among the Uru, Aymara, and Quechua people of the Bolivian Altiplano, a rare DNA sequence became dominant. This adaptation highlights the ongoing biological evolution in humans. It challenges the long-held belief that human evolution slowed down significantly after the emergence of Homo sapiens.
For much of the 21st century, many evolutionary biologists believed that humans evolved slowly in recent millennia. This contrasted with the dramatic transformations earlier in our prehistory. Early studies of modern human DNA found limited genetic variations unique to specific populations. This seemed to confirm the idea of evolutionary stagnation.
Consequently, many scientists believed that recent human history was primarily about cultural changes, like developing agriculture, rather than biological adaptations. The discovery of arsenic tolerance in Andean populations demonstrates the power of natural selection to shape human biology even in recent times. This understanding can inform public health strategies and personalized medicine approaches.