Comparison Of Chloroplast And Mitochondrial Genome Evolution In Plants
Published 1992 · Biology
Plants are unique among eukaryotes in possessing two DNA-containing organelles—the plastid and the mitochondrion. Moreover, the green alga Chlamydomonas reinhardtii has recently been shown to contain a third extranuclear genome—that of the basal body (Hall et al., 1989). Nothing is known about the origin, phylogenetic distribution and evolution of basal body DNA, and therefore this genome will not be considered in this chapter. In contrast, we now possess a rather detailed picture of the tempo and mode of evolution of chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) in land plants. Review of this topic will form the heart of this chapter, as presented in Sects. III–V. Data for both genomes will be presented in an integrated format in order to highlight the striking contrasts in their evolution in land plants. The much more limited evolutionary data base available for algal organelle genomes will be discussed in Sect. VI. All plastid and mitochondrial genomes are of endosymbiotic, bacterial origin. However, as discussed in the next section, considerable uncertainty remains as to the precise number and nature of endosymbioses that have taken place.