[Gene angora enhances the effects of gene waved alopecia in mice]

Interaction between the mutant gene angora-Y (Fgf5(go-Y)) and the mutant gene waved alopecia (wal) in mice has been studied. Gene Fgf5(go-Y) in a homozygous state increases the length of hair of all types, whereas the homozygotes at wal gene display a waved hair with subsequent development of partial alopecia. Crosses between Fgf5(go-Y)/Fgf5(go-Y) and wal/wal mice gave the animals displaying the genotypes +/Fgf5(go-Y) wal/wal and Fgf5(go-Y)/Fgf5(go-Y) wal/walas well as F2 +/+ wal/wal mice. The first signs of alopecia in F2 +/+ wal/wal appear at the same time as in the mutant wal/wal BALB/c mice. This demonstrates that the genetic background has no effect on the expression of mutant gene wal. A single dose of gene Fgf5(go-Y) in +/Fgf5(go-Y) wal/wal mice causes a considerably earlier appearance of the first signs of alopecia compared with the +/+ wal/wal single homozygotes. The signs of alopecia in double homozygotes Fgf5(go-Y)/Fgf5(go-Y) wal/wal appear even earlier than in the mice +/Fgf5(go-Y) wal/wal. By the end of the first month after birth, the majority of double homozygotes have a virtually bold back with preserved scarce long hairs, guard hairs. Alopecia covers also the sides and belly. However, the head retains its hair and the regions of thinned long hairs remain on the limbs and near the tail base. The data obtained demonstrate that gene Fgf5(go-Y) is a modifier of gene wal, as it enhances considerably the effect of gene wal. This appears in an earlier development of alopecia and its more pronounced progress in the mice with genotypes +/Fgf5(go-Y) wal/wal and, particularly, Fgf5(go-Y)/Fgf5(go-Y) wal/wal.