Red on German Shepherds is a rich mahogany color on sections of the coat. It does not come as pure color.
All GSDs called red German Shepherds are a combination of red on specific sections of the coat with darker-colored sections. This darker color can be black, liver/brown, blue, or isabella/lilac usually concentrated on the dog’s dorsal surface. The dorsal surface is the dog’s back surface and sides.
For a German Shepherd due to be pure red with no dark shading or dark hair, two copies of the recessive red gene would need to be present. These dogs would need to have the e/e genotype which blocks any dark-colored pigment to be formed and loaded onto the coat hairs.
Dogs with the e/e genotypes can’t have any black, brown, blue, or lilac hairs.
But for the coat to have a rich red shade, the red pigment should be in high concentration and undiluted. This does not seem to be the case for German Shepherds that are e/e on the E-locus.
All German Shepherds with two copies of recessive red (e/e) have very light coats. Their coats range in shade from blonde to almost white which is known as ivory white. This is because in GSDs the recessive red seems to be inherited together (haplotypes) with another gene known as the intensity gene which reduces the concentration of the red pigments causing them to range in shade from blonde, and cream to ivory white. Blonde to white GSDs have two copies of recessive red (e/e) and intensity genes (i/i) hence none are pure red due to the actions of the intensity genes.
All red or pure red German Shepherds without dark shading do not seem to exist. Rich mahogany red is always combined with darker pigments that are either black, brown/liver, blue, or lilac.
More research is required on the actions of the intensity genes on German Shepherds and how they interact with recessive red.
If you have any questions or feedback, feel free to leave them in the comment section below.
There you go, WOOF!