Colour genes

Marking genes

Merle

Merle rats seemed to disappear in the UK at one point, but imports in 2015/16 brought merle back to the UK fancy. Merle works on the mink gene, and causes uneven distribution of pigments in the coat, causing distinct spots in the coat. This can appear similar to the ‘patchy moults’ which are commonly associated with mink rats, however these are permanent, and do not change with moults.

Genetics: Currently unclear, but requires mink for expression.

NFRS Standard: Merle rats may be shown in pearl and cinnamon pearl. The unique feature is a pattern of dark splash-spots distributed evenly throughout the entire lighter background colour so as to resemble a merle dog. The markings should be numerous and distinct. Eye colour black.
Genetics: Pearl or cinnamon pearl rats with patchy expression of the pearl gene.