Developing genomic information for Holothuria polii (Echinodermata: Holothuroidea), a novel potential aquaculture species

Sea cucumbers (Holothuroidea) are ecologically important organisms for their bioturbation and alkalinization activities of the seabed. They are also important as luxury food and for the production of bioactive compounds and for these reasons they are extensively fished. A few initiatives are also evaluating sea cucumbers as novel species for cultivation in aquaculture systems. In this study we generated sequence information for Holothuria polii, a common sea cucumber species of the Mediterranean Sea, for which no detailed genomic studies have been carried out so far. Whole genome sequence information was produced from an individual whose species identity was obtained by scanning electron microscope analysis of sclerites, which are anatomical features that can discriminate closely related species of the genus Holothuria. Illumina paired end sequencing produced a total of ~210 millions of reads for a about 21 Gbp. Generated data was analyzed against the genome sequence of other echinoderms to characterize several nuclear genes. In addition, the complete mitochondrial genome was assembled and used to evaluate the phylogenetic relationship of H. polii against the other few Holothuroidea species for which the whole mitochondrial DNA (mtDNA) was available. The 15,907 bp H. polii mtDNA sequence has the same gene order already reported for H. scabra, H. forskali and other species of the same family. Cox1 gene sequences were informative for species identification across the genus and could be used for the authentication of commercialized Holothuria spp. These first genomic data we produced for H. polii may constitute starting information to obtain an assembled genome and analyze variability in the Mediterranean populations of this species.