Striatal <i>HTT</i> CAG instability in 10-week-old <i>Hdh^Q111/+</i> mice on different genetic backgrounds.

Graphical representation of striatal CAG instability indices from individual (A) B6, 129, (B6x129).F1 and (B6x129).F2 mice, color-coded based on strain genetic background; and from (B) (B6x129).F2 mice color-coded by genotype at the Mlh1, Msh3 and Msh2 genes (“undetermined” indicates failed genotype). F2 mice homozygous or heterozygous for B6 Mlh1 alleles display significantly higher levels of striatal somatic CAG instability than F2 mice homozygous for 129 Mlh1 alleles (p<0.0001 for both). No relationship could be established between Msh3 or Msh2 genotype and striatal CAG instability. B6.HdhQ111/+, n = 10, CAG116.9±1.2SD; 129.HdhQ111/+, n = 12, CAG110.9±1.2SD; (B6x129).HdhQ111/+ F1, n = 11, CAG114.7±6.4SD; (B6x129).HdhQ111/+ F2, n = 69, CAG107.7±3.2SD. dbSNP markers located within MMR genes: Mlh1, rs30131926 and rs30174694 (concordant genotypes detected with both markers); Msh3, rs29551174; Msh2, rs33609112 and rs49012398 (concordant genotypes detected with both markers). Horizontal bars represent the mean CAG instability indices of the respective groups.