INVOLVEMENT OF REGIONS OF THE 4TH AND 7TH CHROMOSOMES IN THE OPEN-FIELD ACTIVITY OF MICE

Reactivity to a new environment was studied hi mice, using an open-fie ld procedure in two strains, C57BL/6By and ABP/Le, the F-1 populations and the intercrosses F-2 and backcross segregating populations. The a nalysis of the behavioral traits: peripheral and central activities, l eaning, rearing and defecation in the parental strains made it possibl e to show that the ABP/Le strain was more reactive than C57BL/6By. In addition, the study of segregating, for four phenotypic markers, in F- 2 and backcross populations strongly suggested that two autosomal regi ons were involved in the control of open-held behavior: one in chromos omal region comprising the b locus on chromosome 4 and one in chromoso mal region comprising the p locus on chromosome 7.