Stickleback genome-wide replication timing from whole embryo

Developing stickleback embryos were dissociated and sorted for S-phase and G0/G1-phase cell populations. DNA was extracted from each population and sequenced. In a mixed S-phase population, regions that replicate earlier are at higher copy number (up to 2x) than regions that replicate later. The read depth in S-phase, normalized to the read depth in G-phase, thus represents replication timing. Overall design: Replication timing (G0/G1-phase and S-phase cells) from 9 different stickleback populations