Fig. 7

Splice site evolution correlates with both lineage and genome size. Splice site changes are shown for hemocytin (blue text), Tenascin major (Ten-m, turquoise text), and UDP-galactose 4′-epimerase (brown text), mapped onto a species tree of eight insects. Patterns of splice site evolution were inferred based on the most parsimonious changes that could generate the given pattern within a protein sequence alignment of all orthologs (see also Additional file 1: Supplemental Note 6.3 for methodology and data sources). If inferred gains or losses were equally parsimonious, we remained agnostic and present a range for the ancestral number of splice sites present at the base of the tree, where the bracketed number indicates how many ancestral positions are still retained in all species. Along each lineage, subsequent changes are indicated in brackets, with the sign indicating gains (+) or losses (−). Values shown to the right are species-specific changes. The values shown between the D. melanogaster and T. castaneum lineages denote changes that have occurred independently in both species. Colored boxes highlight the largest sources of change, as indicated in the legend. Species are represented by their four-letter abbreviations (as in Fig. 6), and estimated genome sizes are indicated parenthetically (measured size [12, 30, 162, 165, 166]; draft assembly size: GenBank Genome IDs 14741 and 17730). Divergence times are shown in gray and given in millions of years [3]. Abbreviations as in Figs. 4 and 6, and also: Hemipt., hemipteroid assemblage (including F. occidentalis); n.d., no data