Total RNA was extracted from frozen animal cap explants by homogenisation in NETS buffer followed by phenol-chloroform extraction and ethanol precipitation. DNA was removed using DNase I treatment, and RNA was re-purified by phenol–chloroform extraction and ethanol precipitation. RNA quantity was assessed by spectrophotometry and integrity confirmed by agarose gel electrophoresis. RNA-seq libraries were prepared by Novogene using standard Illumina-compatible protocols following poly(A) RNA enrichment and fragmentation, cDNA synthesis, adapter ligation, and PCR amplification.