Fig. 1.

Widespread loss of introns during the evolution of fungi. Ancestral introns were inferred from 1,444 sets of orthologs in 263 fungal species using a Markov model with rates across sites and branch-specific gain and loss rates. Branches are color-coded with intron densities from the median posterior distribution for each node. A list of full names and intron densities are available in supplementary table S2, Supplementary Material online; see also, table 1, figure 2, and supplementary figure S1 and table S1, Supplementary Material online. Green-filled circles denote eight intron-poor species selected for additional analysis. Introns/kb, the number of introns per 1 kb of protein-coding sequence.