Crossbreeding mouse and chinchilla

Question

The MGI Mouse Genome Informatics website states for the Mus musculus 129 strain, popular in biomedical research, that:

Origin: Dunn 1928 from crosses of coat colour stocks from English fanciers and a chinchilla stock from Castle.

Source

However, according to wikipedia, Chinchillas are in the suborder Hystricomorpha, whereas the house mouse is in the Myomorpha suborder of the Rodentia order. From my limited knowledge about species hybridisation, this seems like quite the evolutionary distance for these species to hybridise. How plausible is it that the 129 mouse strain was actually bred through hybridisation efforts between chinchillas and house mice? I'm also open to the possibility that I might've misinterpreted some relevant information.

Answer 1

"Chinchilla" is both a separate rodent, and also a name for a Mus musculus mouse coat color/pattern. Here it's used in the latter context. You may be more familiar with the word "agouti" which is a different color. See for example:

AFRMA Fancy Mice:

Color is to resemble that of the Chinchilla rabbit, with a pearl-gray background, evenly tipped with black, and a slate blue base to the hairs. The belly and the inside of the legs is to be white, the outside of the legs to match the top color. Eye color is black.

Varieties - Ticked - Chinchilla (chi):

The mouse shall be as near as possible to the colour of a chinchilla with slate-blue undercolour and intermediate shade of pearl-grey. Hairs to be evenly tipped with black. Colour of feet on inside white, with remainder of foot the same colour as body - as in the standard for tans. Belly white. Eyes black.

I would have assumed the name was derived simply from the chinchilla, as in a "chinchilla mouse" has a coat that reminds someone of a chinchilla, but that first quote seems to suggest that the route is a bit more circuitous, and perhaps there was first a breed of rabbits which had a coat that reminded someone of a chinchilla coat, and later used the same word to describe a mouse as looking like the rabbit that looks like the chinchilla. I have no other evidence for this, but find it a bit entertaining.