Cyanobacteria

Architects of the earliest microfossils, atmospheric oxygen, and plastids.

Evolutionary timing of the origins of mesophilic sulphate reduction and oxygenic photosynthesis: a phylogenomic dating approach (Abstract)

Blackwell Synergy: Geobiology, Vol 2, Issue 1, pp. 1-20: Evolutionary timing of the origins of mesophilic sulphate reduction and oxygenic photosynthesis: a phylogenomic dating approach (Abstract): "Until recently, the deep-branching relationships in the bacterial domain have been unresolved. A new phylogenetic approach (termed compartmentalization) was able to resolve these deep-branching relationships successfully by using a large number of genes from whole genome sequences and by reducing long branch attraction artefacts. This new, well-resolved phylogenetic tree reveals the evolutionary relationships between diverse bacterial groups that leave important traces in the geological record. It shows that mesophilic sulphate reducers originated before the Cyanobacteria, followed by the origination of sulphur- and pyrite-oxidizing bacteria after oxygen became available in the biosphere. This evolutionary pattern mirrors a similar pattern in the Palaeoproterozoic geological record. Sulphur isotopic fractionation records indicate that large-scale bacterial sulphate reduction began in marine environments around 2.45 billion years ago (Ga), followed by rapid oxygenation of the atmosphere about 2.3 or 2.2 Ga. Oxygenation was then followed by increasing oceanic sulphate concentrations (probably owing to pyrite oxidation and continental weathering), which then resulted in the disappearance of banded iron formations by 1.8 Ga. The similarity between the phylogenetic and geological records suggests that the geochemical changes observed on the Palaeoproterozoic Earth were caused by major origination events in the mesophilic bacteria, and that these geochemical changes then caused additional origination events, such as aerobic respiration. If so, then constraints on divergence dates can be established for many microbial groups, including the Cyanobacter"

Blank, Carrine E. (2004) Evolutionary timing of the origins of mesophilic sulphate reduction and oxygenic photosynthesis: a phylogenomic dating approach. Geobiology 2 (1), 1-20.
doi: 10.1111/ j.1472-4677.2004.00020.x

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