Transcriptomic analysis reveals growth-related genes in juvenile grass carp, Ctenopharyngodon idella

Grass carp has the highest production yield among all the farmed fish species around the world. But the molecular and genetic basis of growth traits is inadequately understood in this fish. In the present study, we apply whole-transcriptome sequencing to identify genes whose expression is different between fast and slow growing grass carp. We identified 1178 differentially expressed genes (DEGs), among which 270 were upregulated in the fast growing group and 908 upregulated in the slow growing group. The GO enrichment analysis revealed that DEGs was significantly enriched in protein synthesis and export machinery, cell division and development and metabolism, suggesting that cell division and metabolism may play key roles in development processes of fish. KEGG pathway analysis showed that MAPK signaling pathway may play a prominent role in growth difference. In addition, the majority of genes in immune responses related pathway were upregulated in the slow growing individuals. These results provide some valuable resources for understanding the molecular mechanisms of growth traits in fish.