Fig. 1.

Patterns of chemosensory-related gene (CRG) family evolution in the Arthropoda. Gene family gain events (red plus sign) are shown along the branches. Numbers of GR, IR, CSP, OR, and OBP genes for representative species are shown in the right-hand columns. Letters to the right of the columns indicate the taxa used in the analysis, listed below. Green dots on the phylogeny indicate terrestrial colonization of most members of a lineage. Numbers of CRG genes were obtained from genome sequence data, except for four species (Acropora millepora, Amphibalanus amphitrite, Penaeus monodon, and Artemia franciscana: indicated with underline and gray font letters to the right of the columns), for which CRG genes were obtained from transcriptome data. A consensus of the arthropod phylogeny was obtained from von Reumont et al. (2012), Oakley et al. (2013), and Sasaki et al. (2013). Branching resolution among earliest animal lineages were obtained from Parfrey et al. (2010), Moroz et al. (2014), and Whelan et al. (2015). The gray branches indicate the protistan phyla and the gray-dashed branches are the fungal phyla. Numbers of CRG genes obtained through our analyses are indicated by asterisks to the left of the columns above, whereas references are provided (below) for data obtained from other studies. Species shown in the figure above are as follows: