Analysis of gene expression level changes during the regeneration of the hemichordate posterior during the first 96 hours of regeneration. Overall design: Animals were bisected, then collected at eight experimental timepoints - 2 hours, 4 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours, 96 hours, with a minimum of four replicates for each timepoint. Additionally, four healthy and intact animals were bisected and immediately collected to serve as reference controls.