Integrated miRNA-mRNA analysis provides potential biomarkers for selective breeding in bay scallop (Argopecten irradians).

Growth traits were compared between selected Argopecten irradians (BA) and non-selected A. irradians (NA; as a control). The results indicated that 1) the BA line exhibited greater average body weight and adductor muscle wet weight increase compared with the NA line at the same age of 10 months. 2) Comparative and integrated microRNA (miRNA) and mRNA transcriptome analyses identified 3373 differentially expressed genes (DEGs), 33 differentially expressed miRNAs (DEMs), and 39 "DEM-DEG" pairs in the BA line compared with the control. DEGs, DEMs, and "DEM-DEG" pairs involved in insulin signaling, immune related pathways, and actin cytoskeleton regulation were identified as candidates correlated with growth improvement in the BA line. A total of 259 positively selected genes were also identified. Collectively, our observations in this study will enrich the molecular information for A. irradians and provide potential biomarkers for future selective breeding and new seed creation in scallops.