Figure 2 - . Occurrence of group I introns in different genomes and cellular compartments. The asterisks emphasize lineages within the tree of life that are notably rich in group I introns, encompassing fungi, plants, and red and green algae. In metazoans, group I introns have been found in non-bilaterian basal lineages (sponges, cnidarians, and placozoans) and in some species of sharks (Corsaro and Venditti, 2020; Mukhopadhyay and Hausner, 2021).