These pronounced similarities in the phenotype as well as the co-segregation of the Crb1RD8/RD8 mutation with the early onset retinal degeneration in the different re-derived chemokine knockout mice indicate that the retinal degeneration observed in original CCDKO mice is the consequence of the Crb1RD8/RD8 mutation and not due to the combined double knockout of Ccl2 and Cx3cr1 as previously reported [41]. The gene discussed is CX3CR1; the disease is retinal degeneration.