Darwin's explanation of evolution, [Woese and Goldenfeld] argue, even in its sophisticated modern form, applies only to a recent phase of life on Earth.
At the root of this idea is overwhelming recent evidence for horizontal gene transfer - in which organisms acquire genetic material "horizontally" from other organisms around them, rather than vertically from their parents or ancestors. The donor organisms may not even be the same species. […]
In the Darwinian model, evolutionary change occurs because individuals with genes associated with successful traits are more likely to pass these on to the next generation. In horizontal gene transfer, by contrast, change is not a function of the individual or of changes from generation to generation, but of all the microbes able to share genetic material. […]
For the researchers the conclusion is inescapable: the genetic code must have arisen in an earlier evolutionary phase dominated by horizontal gene transfer.