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Figure 3 | BMC Evolutionary Biology

Figure 3

From: An updated 18S rRNA phylogeny of tunicates based on mixture and secondary structure models

Figure 3

Analysis of base-composition heterogeneity. Principal component analysis (PCA) of the base composition of 18S rRNA from the 110-taxa dataset considering all nucleotide sites. The graph shows the first two principal components (PC), which contribute 96% and 2% of the total variance, respectively. The main component represents the variance along the AT versus GC axis, with the AT-rich Appendicularia, and the GC-rich Aplousobranchia at the two extremes.

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