Genetic dominance for low activity in infant mice.

Abstract

Locomotor activity of 2,140 four-day-old inbred, hybrid, and wild mice was measured. Consonant with the prediction that high rates of locomotor activity would be maladaptive in infant mice, hybrids were less active than inbred lines. A triple test cross analysis indicated low heritability and nearly complete dominance toward low activity. Mice from wild stock were even less active than hybrids, which suggests that selection pressures for low infantile activity have relaxed during laboratory domestication. A test is described for estimating changes in selection pressures resulting from laboratory rearing.

QUANTITATIVE GENETIC ANALYSIS OF TEMPERATURE REGULATION INMUS MUSCULUS. II. DIALLEL ANALYSIS OF INDIVIDUAL TRAITS

“…The large proportion ofadditive genetic variance and slight dominance toward high performance were consonant with results of previous extensive studies involving inbred strains and selected lines of laboratory rats (Hewitt et al, 1981). In an examination of ecologically relevant vs. "nonsense" behavior in house mice, Henderson (1978Henderson ( , 1981 compared two kinds oflocomotor activity in 11-day-old pups. The genetic architecture reflected the relative "adaptiveness" of the behavior, with open-field activity (a situation unlikely to be encountered by infant mice) exhibiting only additive genetic variance.…”

GABA and behavioral inhibition in the neonatal rat pup

“…Indeed, the inheritance of locomotor activity is characterized by a pattern of nearly complete dominance for low activity in neonatal mice, suggesting that low activity may be adaptive in the early postnatal period (Henderson 1978). Although it has often been assumed that the neonatal rat pup is simply not capable of much behaviorally, under certain circumstances (e.g., in the presence of milk or when stroked with a soft brush somewhat mimicking maternal licking -see Pedersen et al 1982) neonatal rat pups do become quite active, exhibiting behavioral repertoires that may not be elicited by isolated pups in the absence of such sensory stimulation until much later in ontogeny.…”

Mouse (Mus) burrows: Effects of age, strain, and domestication

“…Why wasn't the difference between wild and domestic Mus greater? There is some evidence that domestication of the laboratory mouse has produced a relaxation of the expression of other activity-related behaviors (Henderson, 1978). Perhaps the most likely explanation is one that degeneracy theorists would do well to remember: Laboratory mice and rats are recent domesticants (Zeuner, 1963)-so recent, in fact, that we cannot legitimately expect great changes in most behaviors.…”