A. Representative repeat PCR profiles from the livers of 10-month old Lig4+/+ and Lig4fl/fl mice with 150 repeats. The repeat PCR profiles from heart, an organ that does not show expansions, are included to indicate the original inherited allele size. Superimposed on the liver profiles is the calculated normal distribution profile of each allele. The numbers above each liver panel indicate the number of repeats added relative to the original allele. The black dotted line in each panel indicates the size of the original inherited allele, while the gray dotted line indicates the average size of the expanded alleles. The numbers adjacent to each peak in the PCR profile are the respective SDs. B. Average repeats added to different tissues of Lig4+/+ and Lig4fl/fl mice. Each panel shows the average of five 10-month old animals with ~150 repeats. C. Average standard deviations of the stable and expanded PM alleles in the livers of the Lig4+/+ and Lig4fl/fl mice shown in Panel B. The error bars represent the standard error. * p= 0.02, ** p= 0.002, ns: not significant.