Mr. Dohm et al., EXERCISE PHYSIOLOGY OF WILD AND RANDOM-BRED LABORATORY HOUSE MICE ANDTHEIR RECIPROCAL HYBRIDS, American journal of physiology. Regulatory, integrative and comparative physiology, 36(4), 1994, pp. 180001098-180001108
We conducted a ''common garden'' experiment to compare aspects of exer
cise physiology and voluntary wheel-running behavior in wild and rando
m-bred (i.e., non-inbred) laboratory house mice and their reciprocal c
rosses. Analysis of covariance indicated that, after effects of body m
ass and other appropriate covariates (e.g., age at testing) were accou
nted for, wild (range 2.46-3.30 m/s, n = 12) and hybrid (range 1.69-3.
30 m/s, n = 24) mice exhibited forced maximal sprint running speeds th
at averaged similar to 50% higher than those of random-bred laboratory
mice (range 1.11-2.12 m/s, n = 19). Wild and hybrid mice also had sig
nificantly higher (+ 22%) mass-corrected maximal rates of oxygen consu
mption (VO2max) during forced exercise and greater (+ 12%) relative ve
ntricle masses than lab mice. Wild and hybrid mice also showed statist
ically higher swimming endurance times relative to body mass than lab
mice, although these differences were insignificant when body mass was
not used as a covariate. No significant differences were found for re
lative gastrocnemius muscle mass, liver mass, hematocrit, or blood hem
oglobin content. During a 7-day test on voluntary activity wheels, bot
h wild and hybrid mice ran significantly more total revolutions (+ 101
%), ran at higher average velocities when they were active (+ 69%), an
d exhibited higher maximum revolutions in any single 1-min period (+ 4
1% on the 7th day of testing), but the total number of active 1-min in
tervals did not differ significantly among groups. In general, the beh
avioral and/or whole organism performance traits showed greater differ
ences than the lower-level traits; thus, during the domestication of h
ouse mice, behavior may have evolved more rapidly than physiology.