Abstract
On the macroevolutionary timescale, does trait evolution proceed gradually or by rapid bursts (pulses) separated by long periods of stasis? Although studies have shown pulsed evolution is prevalent in animals, our knowledge about the tempo and mode of evolution across the tree of life is very limited. This long-standing debate calls for a test in bacteria and archaea, the most ancient and diverse forms of life with unique population genetic properties. Using a likelihood-based framework, we analyzed patterns of microbial genomic trait evolution on a broad macroevolutionary timescale. Here we show that pulsed evolution is both prevalent and predominant in microbes. For the first time, we detected two distinct types of pulsed evolution that are predicted by the punctuated equilibrium and quantum evolution theories. Our findings suggest that major bacterial lineages originated in quick bursts and pulsed evolution is common across the tree of life despite drastically different population genetic properties of animals, plants and microbes.
Competing Interest Statement
The authors have declared no competing interest.