Comparisons of qualitative genotyping for the mutant hSOD1 locus in two independently-derived colonies. Progeny derived from commercial breeders exhibited more than a two-fold decrease in the genomic G37R signature compared to collaborator derived offspring. Results are presented as the relative difference between the PCR cycle threshold (CT) values of the housekeeping (CJUN) and target (mutant SOD1) genes, raised to the second power. Kruskal-Wallis non-parametric analysis followed by Dunn’s Multiple Comparison test, indicated significant inter-source differences (p < 0.001, 0.01) while failing to differentiate loci heterogeneity from within each source. Collaborator- ♂ vs. Commercial-♂ (p < 0.001); Collaborator- ♂ vs. Commercial-♀ (p < 0.001); Collaborator- ♀ vs. Commercial-♂ (p < 0.01); Collaborator- ♀ vs. Commercial-♀ (p < 0.001).