People typically think about evolution as a linear process where, within a species, the classic adage of “survival of the fittest” is constantly at play. New DNA mutations arise and get passed from parents to offspring. If any genetic changes prove to be beneficial, they might give those young a survival edge.
Over the great span of time – through the slow closing of a land bridge here or the rise of a mountain range there – species eventually split. They go on evolving slowly along their own trajectories with their own unique mutations. That’s the process that over the past 3.5 billion years has created the millions of branches on the evolutionary tree of life.
However, new genome sequencing data reveals an unexpected twist to this long evolutionary story. It turns out that the boundaries between species on their own branches of this tree are a little more permeable than previously thought. Rather than waiting around for new mutations to solve a particular problem, interbreeding between different species can introduce ready-made genetic advantages.
Unraveling the story of life, one genome at a time
