Fig. 2.

Differential gene size expansion during animal evolution. a Phylogenomic tree showing median gene length of the top 10% longest genes in each genome as a bargraph. All eukaryotic kingdoms are represented, with Metazoa further subdivided into animals with notochords (Chordata) and animals without notochords (here labeled as Metazoa). Branch lengths were obtained from TimeTree.org [22], and scale bar shows 100 million years. b Boxplots of median gene length of long genes of each genome in kilobases aggregated by clade. c Boxplots of long gene intronic sequence versus exonic sequence per clade. d Boxplots showing median number of exons of each gene for each species grouped by clade. This extends similar analyses by Lynch et al. [40] and Francis and Wörheide [39] of exon/intron content