[Occurrence of white Japanese field vole (Microtus montebelli) in the laboratory]

Some field voles with a white coat color were found in the breeding process in the laboratory, originated from a wild population captured in the riverside of the Arakawa in Okegawa, Saitama prefecture in Japan. They had been raised in a room and fed with pelleted feed for herbivore. An attempt was made to analyze their breeding records and mode of inheritance for the white coat color. As a result, the average litter size was 3.80 +/- 1.52, and the age of the first birth was 121 +/- 46.8 in days. This shows that most of the characters of the white voles are not different from those of the agouti ones. From the results of the mating tests, it might be concluded that an autosomal recessive gene was responsible for the appearance of the white coat color.