| Abstract: | In 12 inbred strains of mice there was no general correlation between litter size and parental life span within strains, although a significant between-strain correlation of +0.69 was found between mean life span of the dams and the mean size of their litters. When data for AKR/J mice, which characteristically die early from leukemia, were excluded, the correlation was increased to +0.90 for the remaining 11 strains. These findings indicate that the correlation is of genetic origin-that is, that genes affecting a dam's life span also affect the size of her litters. |
