Colour genes

Marking genes

Agouti

The agouti gene is one which most fanciers will recognise the effects of, and usually it’s very clear and easy to spot the effects of this gene. The alleles at this locus are:

  • A– agouti, wild type. The fur on the back and sides is grey at the roots, then there is a band of yellow, then black tips (this is often referred to as ticking). On the belly there is less black pigment and almost no yellow pigment, so the belly looks silvery grey.
  • a – non-agouti. The fur lacks the yellow banding, so it is the same colour from root to tip. The belly is no longer paler, so the rat is the same colour all over.

A variety has been bred in the US which is theorised to be melanistic agouti (am), but this hasn’t been imported into the UK yet.

 

A-: Agouti

aa: Non-agouti