Akane Kawaguchi

Highlights • Epigenetic profiling of axolotl limb CT cells provides important resource data • Histone H3K27me3 is associated with limb segment identity and developmental history • Transcriptional cues initiating regeneration might be conserved in regenerative animals Summary The salamander limb correctly regenerates missing limb segments because connective tissue cells have segment-specific identities, termed “positional information”.

Significance The axolotl is an important model organism because it is a tetrapod with a similar body plan to humans. Unlike humans, the axolotl regenerates limbs and other complex tissues. Therefore, the axolotl contributes to understanding evolution, development, and regeneration. With sophisticated tools for gene modification and tissue labeling, a fully assembled genome sequence was a sorely missing resource. Assembly was difficult because the genome size is 10× that of humans.