Genetics

C-locus

5. Extreme dilution, c^e

The extreme dilution gene is lower on the dominance scale than c^ch within the c-series. It has an even stronger effect on the yellow pigment than the chinchilla gene. Furthermore, this gene is the first one in the series to have a strong effect on black pigment as well. c^e dilutes brown pigment less than black, which makes for an interesting effect - see 5.1.4. c^e mice tend to darken with age and often molt streaky.

5.1. Homozygous Forms

5.1.1. c^e with A^y

This gene "wipes out" (dilutes) yellow pigment completely. Therefore A^y/* -- c^e/c^e mice are black eyed whites, suffering from all the problems associated with the dominant yellow colours. Add the pink-eyed gene to the mix and you have a pink-eyed white mouse.

5.1.2. c^e with A

Agouti and c^e make for a dirty brownish colouring, which makes the mouse look streaky and a bit dirty. The usual agouti pattern of a single hair's pigmentation doesn't show very well, the base of the hair being lighter and the tip darker. The mouse is slightly lighter than its nonagouti black representative.

Black Eyed white, Ay/* ce/ce pic: Arttu Väisälä

Beige, a/a ce/ce pic: Arttu Väisälä

5.1.3. c^e with a^t

The ?tanned? extreme dilution homozygotes have a completely white belly because of the strong effect this gene has on the yellow pigment. Well, why should the breeders use the more difficult chinchilla gene when breeding Foxes, rather than this one? -you might ask. The simple answer is: You don't have much of a choice with colours and wouldn't definitely get black fox and such. While the belly is reduced to pure white, the top colour will also be diluted. This top colour varies a bit, the lightest being a greyish shade of light tan (this is called beige in many standards) to the darkest, which is coffee-with-cream in colour (this is called coffee in many standards). With blue dilution added you'll get smoke fox.

5.1.4. c^e with a

As mentioned above, c^e dilutes both black and brown, but brown less than black. Therefore a/a B/* c^e/c^e P/* and a/a b/b c^e/c^e P/* are both Beige, the latter with dark ruby eyes. a/a b^c/* c^e/c^e P/* is coffee - that is, darker than extreme dilution on a self black background.