HORIZONTAL TRANSFER OF GENES-CODING FOR THE PHOTOSYNTHETIC REACTION CENTERS OF PURPLE BACTERIA

Phylogenetic trees were drawn and analyzed based on the nucleotide seq uences of the 1.5-kb gene fragment coding for the L and M subunits of the photochemical reaction center of various purple photosynthetic bac teria. These trees are mostly consistent with phylogenetic trees based on 16S rRNA and soluble cytochrome c, but differ in some significant details. This inconsistency implies horizontal transfer of the genes t hat code for the photosynthetic apparatus in purple bacteria. Possibil ities of similar transfers of photosynthesis genes during the evolutio n of photosynthesis are discussed especially for the establishment of oxygenic photosynthesis.