In our comparison of historical strains with the newly expanded BXD lines (BXD Sub-population effects), we evaluated differences among the three groups of BXD RI lines tested simultaneously for all 257 measures. These were BXD 1–32 (Taylor et al. 1977), BXD 33–42 (Taylor et al. 1999) and BXD 43–100 (Peirce et al. 2004). Only the adrenal weight measures show any significant differences among the three groups of strains for the left (P-value = 3.23E–04) and right (P-value = 1.99 E–04) adrenal weights, when sup-population means are considered. Below we address the issue of mapping in the combined sub-populations.
