Fig. 4: Diversification of SAR202 Baeyer–Villiger monooxygenase (BVMO) genes and its temporal correlation with the evolution of Earth’s atmospheric O2 levels.
a Evolution of the per-gene diversification rate of the SAR202 BVMO genes over geologic time. The two vertical dashed lines represent the Archean/Proterozoic boundary and Proterozoic/Phanerozoic boundary, respectively. Three positive peaks stand out, during the Neoarchean/Paleoproterozoic (around 2500 Ma), the Middle/Late Mesoproterozoic (around 1200 Ma), and the Late Paleozoic/Early Mesozoic (around 300–200 Ma), corresponding, respectively, to the time of the Great Oxidation Event, the rapid divergence of eukaryotic marine algae, and the Permo-Carboniferous O2 pulse. b The temporal correlation between the SAR202 BVMO diversification rate (blue) and Earth’s atmospheric O2 level (red) in the Phanerozoic. The red dots from 100 Ma to 500 Ma are the moving averages of the O2 levels in45, using an averaging window of 200 Myr, which is the uncertainty range (i.e., 95% confidence interval) of the age distributions in the Phanerozoic on the gene tree chronogram of BVMO homologs (Supplementary Fig. 4). The O2 concentration at time 0 is the present atmospheric level (PAL).
