Principal components analysis of base frequencies among mitochondrial genome sequences.

<p><b>A</b> Plot of the first principal component against the second principal component (explaining 93% and 5% of the variability, respectively). <b>B</b> Boxplot of PC1 according to insect orders. An ANOVA of the first principal component shows that the base composition in Hymenoptera is significantly biased relative to the other orders (<i>P</i><0.01 for all pairwise comparisons involving Hymenoptera), due to very high AT frequencies. Samples are color-coded based on order-level taxonomic affiliations (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032826#pone-0032826-g002" target="_blank">Fig. 2</a>).