Bacteria have remarkably diverse base composition in their genomes, with many well studied cases of rapid GC reduction associated with obligate symbiosis and genome streamlining in poor environments. But we don’t really understand how GC content generally changes in evolutionary time. To find out, Saurabh tested different evolutionary models of change in GC content in a phylogenetic context. He found that a model with both gradual and occasional sudden changes was the best fit to the data, with many big jumps in genome GC occurring in all bacterial groups that were analysed. Surprisingly, these jumps were almost evenly split between those with large increases in GC content, and those with decreased GC. The former remain poorly explored, and demand more attention! Read the paper to find more.
AdaptationLab 