Differential rates of aging in natural populations of old-field mice (Peromyscus polionotus).

Lipofuscin accumulation in cerebellar Purkinje cells was studied in two natural populations of old-field mice (Peromyscus polionotus). Chronological age was estimated by assaying water-insoluble proteins in the eye lens. The number of fluorescent lipofuscin granules per cell was used as an index of physiological age. In both populations, lipofuscin accumulation began at an age of about two months and increased linearly thereafter until the maximum age included in the study (322 days). Sex did not significantly affect the rate of accumulation in either population. The populations did differ in their rates of aging, however. The population with faster rate of lipofuscin accumulation had higher reproductive effort and/or greater adult mortality, and lived in poorer quality habitat. Although genetic influences cannot be discounted, environmental factors were probably responsible for differences in rates of lipofuscin accumulation.