How One Child’s Sickle Cell Mutation Helped Protect the World From Malaria

How One Child’s Sickle Cell Mutation
Helped Protect the World From Malaria

The genetic mutation arose 7,300 years ago in just one
person in West Africa, scientists reported on Thursday.
Its advantage: a shield against rampant malaria.

 Carl Zimmer

A false-color image of healthy red blood cells with some sickle cells, the defective cells that die quickly and cause sickle cell anemia. Sickle cells are the result of a mutation that scientists say arose in a single person in West Africa more than 7,000 years ago. Credit Eye of Science/Science Source

 Thousands of years ago, a special child was born in the Sahara. At the time, this was not a desert; it was a green belt of savannas, woodlands, lakes and rivers. Bands of hunter-gatherers thrived there, catching fish and spearing hippos.

A genetic mutation had altered the child’s hemoglobin, the molecule in red blood cells that ferries oxygen through the body. It was not harmful; there are two copies of every gene, and the child’s other hemoglobin gene was normal. The child survived, had a family and passed down the mutation to future generations.

As the greenery turned to desert, the descendants of the hunter-gatherers became cattle-herders and farmers, and moved to other parts of Africa. The mutation endured over generations, and for good reason. People who carried one mutated gene were protected against one of the biggest threats to humans in the region: malaria…