April 2018

Chronological Clues to Life’s Early History Lurk in Gene Transfers

To date the branches on the evolutionary tree of life, researchers are looking at horizontal gene transfers among ancient microorganisms, which once seemed only to muddle the record.

By Jordana Cepelewicz

Scientists who want to uncover the details of life’s 3.8-billion-year history on Earth find themselves in murky territory as soon as they look earlier than half a billion years ago. Before then, microorganisms dominated the planet, but—unlike the animals and plants that later emerged—they left behind barely any fossils to mark their ancient pasts, and attempts to infer their family trees from their genes have proved frustrating.

But two papers published earlier this month in Nature Ecology & Evolution are poised to bring greater clarity to the study of evolution. One has already provided additional evidence for the role that early life played 3.5 billion years ago. The key to their success lay in finding ways to exploit what many researchers have regarded as an obstacle to progress rather than a tool.

Reprinted with permission from Quanta Magazine's Abstractions blog.