Characterization of the spotted seal Phoca largha transcriptome using Illumina paired-end sequencing and development of SSR markers.

Next-generation sequencing provides a powerful new approach for developing functional genomic tools for non-model species. This study aims to investigate the spotted seal (Phoca largha) transcriptome by the approach of Illumina paired-end sequencing technology. We obtained a total of 52,146,394 reads for the mixed tissues of liver and spleen from spotted seal. The de novo assemblies yielded 354,014 contigs and 178,466 unigenes. In addition, bioinformatics analysis revealed a total of 4425 simple sequence repeats (SSRs). Fifty SSRs were randomly selected to validate amplification and determine the degree of polymorphism in the genomic DNA pools. Thirty-five primer pairs successfully amplified expected DNA fragments and detected significant polymorphism among 28 spotted seal individuals. These results contribute to the understanding of the genetic makeup of spotted seal transcriptome and provide useful information for functional genomic research in this species.