A male rat "SRR-Do Your Best" was introduced from American fancy rat colony (Spoiled Ratten Rattery: SRR, in Kansas City, Missouri) to Kyoto University on July 13, 2005. Inbreeding started from F1 progeny of male "SRR-Do Your Best" and a female PVG/Seac.
Siamese mutation (pigmentation on the edge of nose, hip and ear)a missense mutation in exon 1 of the tyrosinase gene, S79P, was responsible for sia , and satin mutation (rough fur).
Maintained by crossing of homozygous and satin heterozygous. Poor breeding performance. Young females and old males are suitable for breeding. Id est, we start smear test at 7 weeks of age and cross females with their father (parent-offspring mating).