Genomic expansion in the dark: A repeat-rich genome of a cave-dwelling remipede sheds light on the evolution of the hexapod sister group.

A chromosome-level genome assembly for the cave remipede Xibalbanus tulumensis spans 8.05 Gb across 30 scaffolds, revealing a repeat-rich genome where intronic and repetitive elements make up ~71%.

• Why it matters: Remipedes are key to Pancrustacea–Hexapoda relationships, but high-quality genomes have been hard to obtain due to habitat access and fragility outside their cave environment.
• What they did: The team generated a highly contiguous, chromosome-scale assembly and assessed completeness using arthropod ortholog recovery (>97%) and microRNA completeness (94%), then analyzed repeats, gene families, venom genes, and macrosynteny.
• The result: Genome expansion is linked to intronic and repetitive element proliferation, while macrosynteny retains ancient fusion-with-mixing signatures and similarity to basally branching insect chromosome architecture, enabling a first genomic framework for Remipedia.

AI summary of the abstract · may contain errors · not medical advice · read the paper.