Extreme mitochondrial genome complexity in the calcaronean sponge Sycon ciliatum (Fabricius, 1780): fragmentation, gene duplication and mRNA editing

Abstract Mitochondrial genomes (mt-genomes) of calcaronean sponges are among the most unusual in Metazoa. They are fragmented into multiple linear chromosomes (mt-chromosomes) and often rely on insertional mRNA editing to generate functional transcripts. These unusual features have precluded complete characterization of calcaronean mt-genomes using short-read sequencing technologies. Here, we assembled and analyzed the mt-genome of Sycon ciliatum (Fabricius, 1780) using HiFi PacBio data generate