Fig. 2

Intein preponderance in pathogenic fungi. a Analysis of inteins in pathogens. Two phyla (Ascomycota + Basidiomycota) were analyzed for a propensity of inteins in pathogens (left). Sequenced genomes of non-pathogenic fungi (gray circles) and pathogenic fungi (black circles) were separated and overlaid with the number of intein-positive genomes from each group (red circles). The overall percentage of intein-containing pathogens is 37.0%, higher than the 16.4% of intein-containing non-pathogens. Ascomycota and Basidiomycota were analyzed separately (right), and also show higher number of intein-containing pathogens (41.8% and 18.6% compared to 27.4% and 3.2%, respectively). Out of available sequenced Ascomycota and Basidiomycota, there are more non-pathogenic genomes sequenced than pathogenic, indicating no sequencing bias. Total genomes analyzed are listed. b Certain fungal lineages have intein-pathogen correlation. Species within an individual phylum (Aspergillus/ascomycete and Cryptococcocus/basidiomycete) were analyzed for a correlation of inteins in pathogens. A condensed phylogenetic tree for Aspergillus species was constructed and annotated by lifestyle (colored circles). Presence of an intein is indicated by bold and red text. While Aspergillus contains many inteins, these do not have a preference for pathogenic species, with a negative correlation coefficient (r = − 0.2). The phylogenetic tree for Cryptococcus shows an absolute correlation (r = 1.0), with the only two known pathogens both having inteins