Fig. 3.

An overlay of representative QTL scans centered at their peak loci mapped with approximately 250 to 300 mice in each study. The entire chromosome containing each representative locus is shown. QTL precision is dramatically improved with new reference populations, including the Collaborative Cross, Diversity Outbred, and to a lesser extent, the expanded BXD recombinant inbred panel. A panel of consomics mice has the ability to narrow a QTL to the resolution of a single chromosome [30]. Thirty-five BXD recombinant inbred strains were used to map basolateral amygdala complex size, resulting in a significant QTL on chromosome 8 [41]. The precision of an F2 cross produces a small, broad significant QTL for bone mineral density on chromosome 7 [42]. From the expanded BXD RI population, a narrow QTL was mapped on chromosome 13 for open field rearing after cocaine [22]. Using mice from the collaborative cross breeding population a QTL for liter size was mapped to a narrow locus on chromosome 6 [14]. Early studies using the Diversity Outcross population of mice reveal high precision loci for light-dark box behavior. CC = Collaborative Cross; DO = Diversity Outbred; F2 = F2 hybrid cross; LOD = Logarithm of odds; MBp = megabase pairs