Evolutionary genomics in Metazoa: the mitochondrial DNA as a model system.

摘要: One of the most important aspects mitochondrial (mt) genome evolution in Metazoa is constancy size and gene content mtDNA, whose plasticity maintained through a great variety rearrangements probably mediated by tRNA genes. The trend mtDNA to maintain same genetic structure within phylum (e.g., Chordata) generally accepted, although more recent reports show that considerable number transpositions are observed also between closely related organisms. Base composition extremely variable. Genome GC often low and, when it increases, two complementary bases distribute asymmetrically, creating, particularly vertebrates, negative GC-skew. In mammals, we have found coding strand base average degree conservation be asymmetric replication mechanism mtDNA. A quantitative measurement evolutionary rate has revealed each various components different rate. Non-synonymous rates specific fall range comparable nuclear genes, whereas synonymous about 22-fold higher mt than genes among conserved but, compared their counterparts, they evolve 100 times faster. Finally, describe some molecular phylogenetic reconstructions which produced unexpected outcomes, might change our vision classification living