In contrast, the cbbA genes may actually encode for two different enzymes (cbbA I and cbbA II ), although there is high identity between the two genes (79%). cbbA II genes are usually confined to simple organisms such as bacteria and fungi while cbbA I is selleck compound present only some bacteria such as R. sphaeroides, but is mostly confined to higher level organisms, including plants and animals. It could be that these two cbbA genes in R. sphaeroides are therefore different although they share high homology as these two enzymes NSC23766 mw are thought to have evolved from convergent evolution [62, 63]. However, in many instances,

there is not markedly homology between cbbA I and cbbA II [63]. Therefore, the physiological significance of these duplications, including those involving cbbA and cbbM, need to be

further studied biochemically and molecularly to better understand their relationships. Ancient gene duplications predated the existence of two chromosomes in R. sphaeroides Since the overwhelming majority of gene PND-1186 mw duplication in the current day R. sphaeroides genome are orthologs and originated prior to or at the time of lineage formation, these findings also validate previous results that a large-scale gene duplication event might have occurred prior to the speciation of R. sphaeroides [28]. and possibly even before the diversification of the α-3 Proteobacteria [52]. The HGT analysis conducted suggests that the contribution of laterally transferred genes to the duplicated genes is not very significant. It must also be noted that with the sequencing of new organisms and strains, it is possible that new ortholog matches to these gene duplications could be found. However,

even so, such new sequences could only change Type-B trees to Type-A trees. Such an understanding aids the mentioned finding that an overwhelming majority of the gene duplications are Type-A. Another issue that must be noted is that it is possible that genes in relatively recent duplications in separate R. sphaeroides strains could have evolved to look more like functional homologs in other species. However, 61.54% of the 234 R. sphaeroides 2.4.1 gene pairs were found in at least one other R. sphaeroides strain. Moreover, the functional constraints data among the 28 common gene pairs Ribonucleotide reductase shows that these pairs are under negative selection and are therefore strongly conserved in function. It is likely then that the majority of gene duplications in R. sphaeroides are undergoing negative selection as well. In addition, the identification of homologous gene pairs among the other three strains of R. sphaeroides reveals that although a gene duplication event may have occurred prior to the formation of R. sphaeroides lineage, significant gene loss or retention has occurred among all R. sphaeroides strains. The distribution of matches on R.