Convergent genome streamlining accompanies independent miniaturization in the world's smallest fishes.

Progenetic miniatures in Cypriniformes share convergent genomic signatures of repeat loss and intron shortening despite independent origins.

• Why it matters: Understanding the genomic basis of extreme body size reduction can reveal fundamental links between development and genome architecture in vertebrates, addressing gaps in knowledge about miniaturization.
• What they did: The study used a time-calibrated phylogeny of 309 species and comparative genomics of 33 high-quality genomes to investigate the evolutionary history and genomic features associated with miniaturization.
• The result: All three independently evolved progenetic miniature lineages exhibit convergent patterns of repeat loss and intron shortening, suggesting predictable structural genomic changes underpin developmental truncation.