low coverage genomic dan of X .birchmanni: male caudal fin
DNA was extracted using the Agencourt DNAdvance kit (Catalog #A48705, Beckman Coulter, Brea, California). The protocol followed manufacturer's instructions except that we used half-reactions. Briefly, ~10 mg of tissue from the caudal fin was mixed with lysis buffer, DTT, and proteinase K and incubated for 16-18 hours at 55oC. Lysed tissue was mixed with 50 l Bind 1 buffer and Bind 2 buffer to bind the DNA to magnetic beads, then washed three times with 70% ethanol. DNA was eluted in 50 l elution buffer. Extracted DNA was quantified using the Nanodrop 8000 (Thermo Fisher Scientific, Waltham, MA).