Prokaryotes evolution

Battistuzzi FU, Feijao A, Hedges SB A genomic timescale of prokaryote evolution insights into the origin of methanogenesis, phototrophy, and the colonization of land. BMC Evol Biol 2004, 4 44. 

Still more confusion plagued early researches, when it was not realized that the biosynthetic routes to thiamine in prokaryotes and eukaryotes are quite different, a fact not expected at the outset. Thus, evidence collected from the study of yeast could not be transposed to bacteria, and vice-versa. For instance, formate is a most efficient precursor of one of the carbon atoms of the pyrimidine part of thiamine (pyramine), both in yeasts and enterobacteria, but incorporates at C-2 in bacteria and at C-4 in yeast. However, as is briefly covered in Section VIII, this dichotomy of pathways might have a deep significance in the perspective of biochemical evolution during primitive life on Earth. 

Redundancy is seen when cells have available more than one protein for the same function. In such a situation, during evolution, one of the proteins - and the corresponding DNA - can be co-opted for another function. For instance, the prokaryotic protein FtsA and the eukaryotic protein actin are believed to be derived from a common ancestor. Both bind ATP but, in spite of structural similarity, are only 20% identical in sequence.24 They... 

During prebiotic times, water-soluble ferrous iron was present and was used in the first stage of life, while copper was in the water-insoluble Cu(I) state, as highly insoluble sulphides. About 109 years ago the metabolism of a primitive prokaryote (cyanobacteria) led to the evolution of dioxygen into the Earth s atmosphere. A... 

First Steps in Evolution of Prokaryotes Anaerobic Chemotypes Four to Three Billion Years Ago... 

First Steps The Evolution of Prokaryotes General Considerations of the... 

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