International Mammalian Genome Society

logo18th International Mouse Genome Conference

17-22 October 2004, Seattle, USA


Nishi A 1, Nishi A 3, Yonekawa H 2, Shiroishi T 1, Shiroishi T 4, Koide T 1, Koide T 3

1 The Graduate University of Advanced Studies, Hayama, Japan, 2 The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan, 3 Mouse Genomics Resource Laboratory, National Institute of Genetics, Mishima, Japan, 4 Mammalian Genetics Laboratory, National Institute of Genetics, Mishima, Japan

The wild-derived mouse strain, MSM/Ms, belongs to a musculs subspecies group, has much different behavioral traits in comparison with C57BL/6, which is a domesiticus subspecies group. MSM/Ms is more active than C57BL/6 in home cage at night phase. And MSM/Ms indicates lower activity than C57BL/6 at open-field test and Light-dark box test. It seemed that MSM/Ms is hyperactive and more anxious than C57BL/6. For identifying genes involved in the difference of behavioral traits between MSM/Ms and C57BL/6, we used consomic strains generated by replacing one of the chromosomes of C57BL/6 by that of MSM. As a first step of this project, we have characterized the behavioral traits of each consomic strains with the use of home-cage activity test and light- dark box test. As a result, C57BL/6-Chr6CMSM, which carries MSM locus from D6Mit166 (1.1cM) to D6Mit12 (49.2cM) showed lower spontaneous activity and higher anxiety than C57BL/6. And there were no apparent sex difference on the test scores of spontaneous activity in this consomic strain, while females of C57BL/6, MSM/Ms and other consomic strains exhibit higher activity than males.

It seemed that the major gene or genes that causes this phenotype are located in the centromere side from D6Mit268 (7.7cM), because C57BL/6-Chr6TMSM, which carries MSM locus from D6Mit268 to D6Mit15 (66.7cM) did not showed similar phenotype as C57BL/6-Chr6CMSM.

Currently, we have been mapping this gene and analyzing the in vivo mechanism of this behavioral trait.

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