Fig. 2From: Effect of genome composition and codon bias on infectious bronchitis virus evolution and adaptation to target tissuesScatter plot based on the first two components of the PCA performed on Z-score (a) and RSCU (b) calculated for all IBV proteins (color-coded). The PCA loadings are represented as arrows. However, for graphical reasons the labels have been removed from (b) and the loading values are provided in Additional file 4. The 95% confidence ellipses around clusters are also reported. The figure was generated using ggplot2 [32]Back to article page