See more from this Division: Overarching Sessions
See more from this Session: Geobiology and Biomineralization: From the Origins of Life to the Origins of Cities
Abstract:
It long has been thought that mitochondrial endosymbiosis was driven by an increase in oxygen in the Earth's atmosphere. This hypothesis is gaining support as geological age constraints on the Great Oxygenation Event (a.k.a. Oxyatmoversion) and molecular clock estimates for the origin of mitochondria converge on the same interval somewhat older than 2 billion years ago. This still-imprecisely delineated interval also hosts a remarkable, >160 million year-long positive excursion in the carbon isotopic record of marine carbonates known as the Lomagundi-Jatuli event. We hypothesize that the duration of this excursion represents the time over which respiratory efficiency increased to ultimately match productivity of oxygenic phototrophs.
Mitochondria evolved from an ancestral member of the Rickettsia group, an early-diverging group in the alpha-Proteobacteria. The only group to diverge more basally is composed entirely of magnetotactic members, including the sequenced Magnetococcus marinus MC-1. We suggest that radiation of this magnetotactic bacterial group immediately prior to the evolution of mitochondria indicates that part of the genetic machinery involved in magnetotaxis evolved at this time and may have facilitated mitochondrial endosymbiosis.
See more from this Division: Overarching Sessions
See more from this Session: Geobiology and Biomineralization: From the Origins of Life to the Origins of Cities