Tde1 enzyme and tagmentation td buffer

ATAC sample preparation was carried out according to the Omni-ATAC-seq protocol (Corces et al. 2017 (link)). For each replicate, embryos were washed once in 1 µm filtered seawater, lysed, and ∼50,000 nuclei were isolated for the transposition reaction using the Illumina TDE1 enzyme and tagmentation (TD) buffer (Cat. No. 20034197 and 20034198) (San Diego, CA, USA). Sequencing libraries for each replicate were amplified via PCR after separately determining the optimal number of amplification cycles for each sample using qPCR as described in (Buenrostro et al. 2015 ), and libraries were purified and size selected using Ampure XP Beads at a 1.8:1 bead volume:library volume (Beckman Coulter, Brea, CA, USA). Library quality and transposition efficiency was accessed using a Fragment Analyzer and PROSize 2.0 (Agilent, Santa Clara, CA) at the Duke University Center for Genomic and Computational Biology. H. erythrogramma and L. variegatus libraries were sequenced on an Illumina HiSeq 4000 instrument using 50 bp SE sequencing. H. tuberculata libraries were sequenced on an Illumina NovaSeq 6000 instrument using 50 bp PE sequencing (only SE were used for data analysis).