NR2E3 and retinal degeneration: To determine if a single modifier gene is able to ameliorate rd7 associated retinal degeneration, we generated an incipient congenic strain that harbors the AKR/J modifier locus on chromosome 11, named Mor7 for modifier of rd7, by backcrossing F2 progeny from our B6.Cg-Nr2e3rd7/rd7 × AKR/J cross to the C57BL/6J inbred strain for six consecutive generations.