This strain is homozygous for the retinal degeneration allele Pde6brd1.
On an agouti background gri homozygotes resemble Tyrc-ch homozygotes. There is a graying of the coat due to a lighter than normal phaeomelanin band. There is no change in eye color. gri homozygotes are slightly smaller than their unaffected littermates. Homozygous females breed well, but homozygous males often do not breed. Testis biopsies failed to identify any sperm abnormalities. The gri mutation does not cause a clotting disorder. (Davisson et al., 2000.)
gri arose spontaneously in C3H/HeSnJ, generation F163, at The Jackson Laboratory in 1983. It has been maintained by backcross-intercross, breeding homozygous females to C3H/HeSnJ then interbreeding their obligate heterozygous offspring to produce homozygous female breeders. This strain was frozen at N37 in 1997/98.
When using the grey intense mouse strain in a publication, please cite the originating article(s) and include JAX stock #002333 in your Materials and Methods section.