The shortest animal introns: insights from parasitic cnidarians.

Ultra-short introns under 30 base pairs independently evolved in at least two parasitic animal lineages, with median lengths as short as 22 bp in Myxozoa.

• Why it matters: Understanding intron length constraints in animals is limited, yet intron size influences gene regulation and genome evolution, making this a key area of genetic research.
• What they did: Using long-read sequencing, the genome of Henneguya salminicola was assembled, revealing median intron lengths of 27 bp, and comparative analysis of 51 genomes identified similar ultra-short introns in other parasitic species.
• The result: The findings show that introns shorter than 30 bp are present in animals and that extreme intron shortening has evolved convergently in parasitic lineages, expanding knowledge of genome diversity and evolution.