title: Development of molecular resources of the copepod Calanus sinicus for its potential ecological applications via a comprehensive transcriptome study
design: Total RNA was extracted from about 50 individuals using RNeasy Mini Kit (Qiagen, Germany) following the manufacturer’s instruction. An RNANano Bioanalysis chip was used to assay the concentration and integrity of RNA. High quality RNA was then provided for RNA-Seq library construction and Illumina sequencing. cDNA library was constructed with ~5 µg initial DNase-treated total RNA following the protocols of the IlluminaTruSeq RNA Sample Preparation Kit (Illumina). After poly (A) mRNA was enriched by beads with Oligo (dT), fragmentation buffer was added for interrupting mRNA to short fragments (200-700 bp). Taking these short fragments as templates, random hexamer-primer was used to synthesize the first-strand cDNA, and then the second-strand was amplified. The double-strand cDNA was purified with Qiagen PCR extraction kit, and the short fragments were connected with sequencing adaptors. The library was PCR amplified and the final library had the yields of ~30 µL of 19.8-21.4 ng/µL with an average length of ~270 bp. After KAPA quantitation and dilution, the library was then sequenced on an IlluminaHiSeq 2000 instrument with 100 bp paired-end (PE) read chemistry by Majorbio Biotechnology Cooperation (Shanghai, China).