Figure 3. Chromosome-specific MLH1 localization patterns in males and females.

The chromosomal locations of MLH1 foci were determined using the same cells as in Figure 2 for ten representative large, medium and small chromosomes. Each chromosome arm was arbitrarily divided into five equal regions – centromeric, proximal, interstitial, distal, and telomeric – and the distribution of MLH1 foci recorded for both chromosome arms for metacentric and sub-metacentric chromosomes or for the q-arm only of acrocentric chromosomes. The distribution differed significantly between females (black) and males (white) for seven of the ten chromosomes: 1 (χ²=24.9; p<0.005), 6 (χ²=24.8; p<0.005), 13 (χ²=13.8; p=0.01), 16 (χ²=32.1; p<0.0001), 18 (χ²=47.7; p<0.0001), 21 (χ²=22.3; p<0.0001), and 22 (χ²=20.8; p<0.0001). However, sex-specific differences were not evident for chromosomes 9 (χ²=15.1; p=0.088), 14 (χ²=5.3; p=0.262), or 15 (χ²=7.8; p=0.101).