Meeting Abstract

P1.116  Jan. 4  Life-History Traits in House Mice Selectively Bred for High Voluntary Wheel-Running Activity KEENEY, B.K.**; MALISCH, J.L.; KELLY, S.A.; HANNON, R.M.; KOLB, E.M.; LONQUITCH, B.P.; MIDDLETON, K.M.; GARLAND, T.Jr.; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside bsahara33@yahoo.com

In rodents, exercise-related changes in reproductive output can range from estrous irregularities to diminished pup survival through weaning. We test the hypothesis that selective breeding for high voluntary wheel running negatively affects reproductive output by analyzing pre- and post-zygotic factors that influence overall reproductive success in house mice. In 4 replicate selected and 4 replicate control lines of mice (generations 45, 46, 47), we compared birth and litter success, pairing-to-pup intervals, litter size, sex ratio, and mass. At generation 45, selected-line females ran on average almost 3 times more revolutions per day than non-selected control lines. Preliminary data show that dams from selected lines have a lower litter success at weaning when compared with control-line dams (1-tailed P = 0.0253), although there are no apparent differences in birth success. Neither litter size, litter mass at weaning, nor the sex ratio of the litter differed significantly between selected and control lines. Analyses of other traits such as estrous cycle length, maternal behaviors, and embryo success based on counts of uterine scars are currently in progress. Supported by NSF IOB-0543429 to T.G.