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Beige Rats Genetics by Debbi J. Needham

Early in our show rat breeding history, many of our rats were bred and traded with Iris Johnson of D61 Rattery.
Unfortunately she is no longer breeding rats. But, she specialized in breeding double recessive beige rats in many
different varieties. We have some rats from her lines, mixed into ours. Many of our rats carry beige or champagne.
There are two recessive genes that cause a rat to become beige or champagne. When a rat inherits a homozygous
pair of these genes, the coat is diluted to a lighter color, along with the eyes of the rat.
So many beige rats have lighter than black colored eyes.
The red eye dilute genes, rr, causes a black rat to become beige and eyes ruby.
The pink eye dilute genes, pp,. causes a black rat to become champagne, a much lighter version of beige,
and its eyes to be very light pink. A topaz has agouti+beige or (A*rr).
At one time, it was believed that rats could not "be" both rr and pp, because of a close link these genes share on
their chromosome. It was believed the rat could inherit only one pairing. Iris went to breeding to see if a rat could
inherit both and it is her and my belief that a rat can. In fact, we had a lilac colored rat, here at Odd Fellows,
born with a pink and a ruby colored eye. The rats that were offspring of pp and rr genes,
did produce offspring that were both beige and champagne and shades in between.
The following are rats that have lived at OFR and/or were bred into our lines.

Beige Rats Genetics by Debbi Needham
2010 Repost 1st posted 2004