Figure 2
From: Evolution of the mitochondrial genome of Metazoa as exemplified by comparison of congeneric species
Structural genomic features of metazoan mtDNA drawn into a phylogenetic context. Detailed explanation of coloured boxes: ‘high architecture (AR) variability’, AR rate calculated on all genes ⩾70 (Table 1); ‘AR variability due to tRNAs’, percentage difference in AR variability ⩾60 (see Δ% in Table 1); ‘max gene strand asymmetry (GSA) variability’, GSA ranging from 0 to almost 1 in most mtDNA of the metazoan group (see GSA in Table 1); ‘one coding strand’, presence of one coding strand (GSA=1) in all, or almost all, mtDNAs of a taxa (Table 3); ‘co-oriented gene clusters’, genome AR with two or four clusters of co-oriented genes in most mtDNA of the metazoan group (Table 3). Low-sampled groups (only 1–2 mtDNAs) are represented by dashed lines. Asterisk indicates partial mtDNA sequences. Names in bold and underlined indicate the availability of congeneric species showing differences in mtDNA AR (Table 5). Long/short branches indicate fast/slow mt nucleotide substitution rates according to the following references: Tunicata (Yokobori et al., 1999, 2005); Platyhelminthes (Lavrov and Lang, 2005); Rotifera Acanthocephala (Steinauer et al., 2005); Chaetognatha (Papillon et al., 2004); Onychophora (Podsiadlowski et al., 2008); Nematoda (Lavrov and Lang, 2005); Bryozoa (Waeschenbach et al., 2006); Chelicerata (Park et al., 2007b); Bivalvia (Knudsen et al., 2006); Cnidaria (Medina et al., 2006) and Porifera (Lavrov and Lang, 2005). The metazoan phylogeny has been obtained from the ‘Tree of life web project’ (http://tolweb.org/tree/phylogeny.html), with the following exceptions: the deuterostome phylogeny was modified according to Zeng and Swalla (2005) and Bourlat et al. (2006); the chordate phylogeny is represented as unresolved, based on the controversy between traditional and molecular data (Delsuc et al., 2006); Echiura and Pogonophora are represented as distinct phyla, although they are often included in Annelida. Myzostomida are not represented, as commonly included in Annelida. Abbreviations: B, Bilateria; D, Deuterostomia; E, Ecdysozoa; L, Lophotrochozoa.
