Coat color Genetics part VI: G-locus (Progressive Greying with Age)

by Annika Farstad
© 2006

Progressive Graying with age is a pigment locus affecting the intensity of dark pigment. Although only two genes were recognised in this series by Little, this may be a more complex locus, or genes that affect graying may reside at more than one locus. The effect of G, in single or double dose, is the replacement of colored by uncolored hairs as the animal ages, very much like premature graying in human beings.

(G) Progressive Graying with age: The Gaying allel progressively lightens pigment with maturity. (Will fade black to grey/silver). The fading may start immediately after birth or after a period of weeks to months has elapsed. The coat often lightens until the dog is around 2 years, but may also continue through the animal's lifetime.

Note that Dilution is different from Progressive Graying. The lightening caused by the Dilution gene (D-locus) is present from birth and influences all pigment, resulting in a blue nose.

(g) Normal Dark: This allel has no effect on pigment (neutral allel)