Metridium sequences
DNA was extracted using QIAGEN DNeasy kits with 2 elution steps of 5 min of elution time. High-quality DNA (~3mg) was extracted. Genomic libraries were prepared from the double-stranded DNA using Nextera DNA Sample Prep Kit (Epicentre Biotechnologies, Madison WI) and shotgun sequenced on a 454 GS-FLX sequencer using the Titanium Sequencing Kit (Roche Diagnostics Corporation, Indianapolis, IN).