ASIP disruption via CRISPR/Cas9 system induces black patches dispersion in Oujiang color common carp

Pigment pattern formation in economical fish remains elusive to date. Oujiang color common carp (Cyprinus carpio var. color) is a variant of common carp with different pigmentation patterns and important farm fish in China. Agouti signaling protein (ASIP) is an endogenous antagonist of melanocortin in the melanogenesis pathway. In this study, two ASIP genes (ASIP 1 and ASIP 2) were first identified in color common carp. Their expression was higher in the pale belly than in the dark dorsal skin, which was consistent with the typical dorsal-ventral expression pattern such as that of wild common carp. In comparison, an unusually higher expression was detected in the non-melanophore side skin than in the melanophore side skin of Oujiang color common carp. Thus, CRISPR/Cas9 was used to disrupt the two ASIP genes in Oujiang color common carp of red with big black patches (RB) pattern. Consequently, the black patches disappeared and the melanophores dispersed along the dorsal skin in the F0 mosaic RB individuals. The findings of this study indicate that the ASIP gene is involved in regulating melanin aggregation and distribution during black patch formation in Oujiang color common carp.