MSM was established as an inbred strain from Japanese wild mice and maintained at the National Institute of Genetics, Mishima, Japan (Moriwaki et al., 2009). (Tokyo, Japan), and bred at the animal facility of the National Institute of Genetics.
The consomic strain that carried a large segment of chromosome 6 was established by replacing chromosome 6 of B6 with that of MSM (Takada et al., 2008).
The results revealed three loci (loci 1–3) that have the effect of reducing home-cage activity and one locus (locus 4) that increases activity.
We also found that the combination of loci 3 and 4 cancels out the effects of the congenic strains, which indicates the existence of a genetic mechanism related to the loss of QTLs.
Before these tests were conducted, the mice were kept individually for 1 day in their home cage to habituate them to isolation.
The home-cage test involved the recording of individual spontaneous home-cage activity from 0600 h on the day after transfer for 3 days. Ltd., Tokyo, Japan), was used to evaluate the spontaneous activity of each mouse in their home cage.
However, grooming or foraging behaviour that occurred in one place was detected less efficiently.
The number of individuals used for each strain and the genotype of microsatellite markers on chromosome 6 are shown.