Reference transcriptome assembly of a protogynous sex change fish, harlequin sandsmelt (Parapercis pulchella).

The harlequin sandsmelt (Parapercis pulchella) is a female-to-male sex change fish in which functional females possess ovotestes that consist of both ovarian and testicular tissues. These features indicate that this species could be an excellent model for studying the flexibility of sex differentiation in vertebrates. However, genetic resources in this species have so far been limited. Therefore, in this study, the reference transcriptome of this fish was constructed through RNA-sequencing, de novo transcriptome assembly, superTranscripts construction, and functional annotations. To obtain as many genes as possible, RNA was extracted from various tissues (brains, gills, hearts, livers, guts, and gonads) and various sexual stages (females, individuals during sex change, and males) and then subjected to sequencing and downstream analyses. As a result, 91,884 representative transcripts with 32,627 protein-coding sequences were generated. 72.2% of protein-coding sequences (23,566 sequences) were functionally annotated. Also, our analysis shows that the superTranscripts method effectively removes redundant sequences from raw-assembled data compared with other strategies. The resultant dataset is a valuable resource for future molecular developmental studies on sex change in P. pulchella.