In(7)4Rl

This chromosomal inversion was discovered at Oak Ridge National Laboratory in descendants of pink-eyed progeny from a cross of an X-ray irradiated male mouse and a T-stock female homozygous for pink-eyed dilution (p). The chromosomal breakpoints were cytologically localized to bands 7C and 7E1. DNA analysis using probes for 13 genes between Ldhc and Igf1r, inclusive, found none of them to be deleted. Complementation by this inversion of all other lethal p alleles against which it was tested suggests the lethal phenotype is associated with the distal breakpoint, in the vicinity of the tyrosinase (Tyr) locus. This is borne out by its failure to complement the embryonic lethal Tyr-locus deletion Tyrc-26DVT. (J:29903, J:29904)