About a quarter of present-day life's DNA blueprint was sketched out by 2.8 billion years ago
Using the genetic equivalent of the Hubble telescope, researchers have peered into the distant past and witnessed an explosion of new genes that happened more than 3 billion years ago.
About 27 percent of all gene families that exist today were born between 3.3 billion and 2.8 billion years ago, two researchers from MIT report online December 19 in Nature. The surge of gene births — which the scientists have dubbed the Archean expansion — predate some important changes in Earth’s early chemistry, including the appearance of large amounts of oxygen in the atmosphere, say evolutionary biologists Eric Alm and Lawrence David.
The study may show how early organisms responded to and helped alter the planet’s chemistry. Daniel Segrè, a computational biologist at Boston University, says that the work provides “insight into really ancient metabolic events.”