Coat types

Body types



The roan gene, also known as husky or European husky, is responsible for the vast majority of worried “why has my rat changed colour?” threads (the remainder being the work of Siamese kittens moulting into their adult coat). This gene has not been scientifically described, but commonly it is given the ro (roan) symbol. The […]


The rat variety called chinchilla is genetically very unlike chinchilla in the mouse. In the mouse the chinchilla colouration is caused by a c-locus mutation, and the white belly either by separate spotting genes or a-locus mutations. In rats, the chinchilla situation is more complicated. The main part of the story is a spotting gene […]

H locus and friends

Most rat markings are created by mutations at the H-locus. The most distinctive is probably the hooded, but the full variety is quite amazing. Opinions on which alleles actually exist in the fancy at the moment differ, but some known alleles include:

H – Wild type, minimum white spotting. He – Quite extensive white spotting […]