Photosynthetic bacteria phylogeny

Recent advances in understanding the phylogeny of photosynthetic prokaryotes have been made by comparing oligonucleotides derived from 16S rRNA [1]. Results of these analyses have renewed general interest in the comparative biochemistry of photosynthetic bacteria, since it is now clear that they are closely related to many non-photosynthetic bacteria. Extensive phylogenetic analysis has indicated that the ancestry of most, if not all, eubacteria and even the ancestry of the cellular organelles of eukaryotes, the mitochondria and chloroplasts, lies deeply entrenched in the history of the photosynthetic bacteria. 

Hiraishi A, Nagashima KVR Katayama Y. 1998. Phylogeny and photosynthetic featnres of Thiobacillus acidophilus and related acidophilic bacteria its transfer to the genns Acidiphilium as Acidiphilium acidophilum comb. nov. Int J Syst Bacteriol 48 1389-98. 

At present neither fossil evidence nor the phylogeny of extant bacteria can tell what the ancestral photosystem looked like and what properties predisposed its possessor among the progenotes to the acquisition of photosynthesis. Another approach to these questions is to search the photosynthetic apparatus itself for possible traces of its history. 

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