A region on chromosome 15 controls intersession habituation in mice.

Habituation to a novel environment, as measured by a change in exploratory activity over time, can be measured both within (intrasession) and across (intersession) sessions. The role of genetics in intrasession habituation has been investigated previously in quantitative trait loci studies, but little attention has been focused on the role of genetics on intersession habituation. We reported recently that inbred strains respond differently in an intersession habituation test. By testing a total of 25 BXD recombinant inbred lines, we were able to map a chromosomal region that strongly influences the way in which mice habituate. This region located on chromosome 15 appears to the major one affecting habituation and accounts for 80% of the genetic variance. We subsequently confirmed this map position by testing (C57BL/6J x DBA/2J) F2 mice.