Construction of cDNA library from muscle tissue of Sepiella maindroni and analysis of expressed sequence tags

A cDNA library from the muscle tissue of Sepiella maindroni was constructed using a cDNA library construction kit.The quality of the library reached 1.2×106 cfu/dm3 in capacity while the rate of recombinant efficiency was as high as 96%.PCR results showed that the average length of the inserts was greater than 1 000 bp.568 clones were selected and sequenced from the library,among which 475 that contained expressed sequence tags(ESTs) were greater than 100 bp.Approximately 200 single-gene clusters were acquired including 41 contigs and 159 single-copy ESTs after an initial assembly,while the redundancy rate was 57.89%.Through retrievals,53(26.5%) ESTs had no obvious homology with any known sequences in the BLASTx(E-value ≥1.00×10-10),and were identified as novel genes.147(73.5%) ESTs had relatively high homology with previously reported genes,including energy-related genes with the highest abundance of ESTs(23.0%),cellular signal transduction(17.5%),cytoskeleton(12.5%),and protein metabolism(9.5%),in addition to heat shock protein 70 and transferrin.These ESTs might facilitate further screening and cloning of uniquely expressed genes in the muscle tissues of Sepiella maindroni and other cephalopods.