Metagenome of Adelie penguin guano
5g of fecal matter was resuspended in 50 SM buffer [0.1 M NaCl, 50 mM Tris/HCl (pH 7.4), 10 mM MgSO4].  The supernatant was recovered after centrifugation at 10 000 g for 20 min. This was then sequentially filtered through 0.45 and 0.2 um (pore size) syringe filters and 3 g of PEG 8000 (Sigma) was mixed gently with 20 ml filtrate. The 15% (w/v) PEG 8000 filtrate solution was then centrifuged for 20 min at 10 000 g and the pellet was resuspended in 2 ml SM buffer at 4 'C overnight. A High Pure Viral Nucleic Acid kit (Roche Diagnostics) was used to purify viral DNA from 200 ul of the final resuspended solution. Rolling-circle amplification with a TempliPhi kit (GE Healthcare) was used to enrich for circular DNA, and this was sequenced on an Illumina HiSeq 2000 sequencer at the Beijing Genomics Institute (Hong Kong).