A QUANTITATIVE GENETIC-ANALYSIS OF TISSUE-SPECIFIC CATALASE ACTIVITY IN MUS-MUSCULUS

Tissue-specific catalase activity in 3-week-old animals from inbred mouse strains 129/ReJ, BALB/c, C3H/HeAnl/Cas-1b, C3H/HeSnJ, C3H/S, C57BL/6J, and Swiss-Webster was found to be highly variable by analysis of variance (P = 0.01). Appropriate crosses were made among strains which were classified as normal (BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (129/ReJ, C57BL/6J), and acatalasemic (C3H/HeAnl/Cas-1b) with respect to blood catalase activity to study the inheritance of the blood, kidney, liver, and lung catalase activity levels in a number of generations (reciprocal F1's, F2, two backcrosses-BC1 and BC2-and some RI lines). Segregation analysis and statistical methods which tested different models of inheritance as well as calculations of heritability were used in an effort to assess and evaluate genetic parameters that affect catalase activity. Results indicate that the inheritance of blood catalase activity in the cross involving acatalasemic and normal (BALB/c, C3H/HeSnJ) strains is compatible with the single-locus difference between the parental strains; however, the difference between the acatalasemic and the hypocatalasemic strain (C57BL/6J) would require additional genetic interaction for a satisfactory explanation. A similar pattern of generalization also applies to the inheritance of kidney catalase activity. The segregation pattern for the liver and lung catalase activity in most crosses is significantly different from the expectations of the single locus model. These results are compatible with the concept that a number of genes must affect tissue-specific catalase activity in mice. These may include previously described (e.g., Ce-1 and Ce-2) or novel genetic regulators/modifiers which interact with a single structural gene (Cas-1) or its product to produce the catalase phenotype characteristic of specific tissues in each strain.