Figure 2.

Change in the PM repeat PCR profiles and σ with age and extent of expansion. The PCR profiles and σs were generated from male mice as previously described [26,27]. (a) Liver PCR profiles of mice of different ages, all with an original allele of ~145 repeats. The arrowhead on the bottom of each panel and the dotted lines indicate the original inherited allele as assessed from tail DNA taken at 3 weeks of age. The numbers above the panels indicate the number of repeats added to the expanded allele. The σ of the stable allele and the expanded allele are shown in black and red, respectively. The examples shown in this panel are derived from previously published work [27]; (b) PCR profiles and corresponding σ for alleles in hearts and brains of 1-year old (155 repeats) and 6-month old (175 and 185 repeats) mice. The number associated with each arrowhead represents the number of repeats in the indicated allele. For the hearts, this number corresponds to the original inherited allele. For the brains, the repeat size reflects a gain of 6–9 repeats from the original allele.