The RAD-seq of nine-spined sticklebacks
DNA was fragmented with restriction enzyme PstI, and P1 adapter with forward amplification primer, sequencing primer and sample-specific barcode were ligated to the digested DNA fragments. Barcoded samples were then sheared randomly and the P2 adapter was added. After a selective polymerase chain reaction (PCR) enrichment step, DNA fragments of 300500 bp in length were gel purified.