Bathyarchaeotal metagenome from Guaymas Basin
DNA were initially fragmented by Covaris and then tested by electrophoresis used 1% agarose gel. Fragmented DNA was combined with an end repair mix and incubated at 20°C for 30 min. The end-repaired DNA was then purified with a QIAquick PCR Purification Kit (Qiagen). Subsequently the A-tailing mix was added and the mixture was incubated at 37°C for 30 min. The purified 3' ends adenylate DNA with adapter and ligation mix were incubated for the ligation reaction at 20°C for 15 min. After this process, the adapter-ligated DNA was selected by running a 2% agarose gel to recover the target fragments. The gel was purified with a QIAquick Gel Extraction kit (Qiagen), and several rounds of PCR amplification with a PCR primer cocktail and PCR master mix were performed to enrich the adapter-ligated DNA fragments. The PCR products were then selected by running another 2% aga rose gel to recover the target fragments. Gel purification was achieved using a QIAquick Gel Extraction kit (Qiagen), and the final libraries were validated by the average molecule length using an Agilent 2100 Bioanalyzer instrument (Agilent DNA 1000 Reagents) and by real-time q-PCR (Taq-Man Probe). The qualified libraries (with a 350 bp insert size) were amplified on cBot to generate a cluster on the flowcell (TruSeq PE Cluster Kit V3–cBot–HS, Illumina). Pair-end sequencing of the amplified flowcell was performed using HiSeq 2000 System (TruSeq SBS KIT-HS V3, Illumina, at BGI-Shenzhen).