Figure 3From: The origin of introns and their role in eukaryogenesis: a compromise solution to the introns-early versus introns-late debate?A brief early history of spliceosomal introns. The scheme shows the inferred sequence of events from the primordial pool of genetic elements to the origin of spliceosomal introns from group II introns invading the host genome upon mitochondrial endosymbiosis.Back to article page