American Fancy Rat & Mouse Association

This article is from the WSSF 2012 AFRMA Rat & Mouse Tales news-magazine.


Blue Mimic Mice

By Virginia Pochmann

From Mouse Review No. 14, Dec. 1989

QWhat is a ‘blue mimic’ gene?

ABlue mimic refers to a number of genes which produce a diluted coat very similar to that produced by the blue-dilution (d) gene. These mice all look like ‘Blues’ to the eye, but some of the genes produce mice with ruby eyes, not black eyes, and one of them gives a coat without ‘mealiness,’ such as d/d mice have. Interestingly, I am personally having my problems with one of these blue-mimic genes, as yet unidentified! The pair of ‘Blue’ mice which I brought back from England, and which look physically identical to each other, are now found to be of completely different genotypes. One of them is doubtless Blue (d/d), and the other a blue-mimic. How do I know this? Because their first litter consisted entirely of Self Blacks! This could only happen if one parent had one genotype such as d/d (Blue) and the other something else, such as ‘leaden’ (ln/ln). (Leaden is one of the blue mimics.) In this case, one parent would be genetically d/d Ln/Ln, and the other parent would be D/D In/In . . . and ALL the babies would be D/d Ln/ln (BLACK).

When these babies are mated to each other, I will expect to find BOTH kinds of Blues segregating out, but still won’t be able to tell them apart.

Ed. Note: Leaden Tan does not suffer from the dilution of the tan as in the normal Blue Tan (dilute gene dd) so you can get Blue Tan (Leaden Tan) that has the rich dark orange bellies seen in other Tans.

Other Blue mimic genes are Ashen ash and Gunmetal gm.

July 21, 2015