Fluctuating Asymmetry in relation to single housing versus group housing in three inbred mouse strains

Abstract

Fluctuating asymmetry (FA) reflects small, random deviations from symmetry in otherwise bilaterally  symmetrical characters and has been used to detect harmful conditions such as environmental and genomic  stress in growing animals and humans. The development of FA may be related to the balance between  canalization (the ability of the genotype to develop a constant phenotype under changing environments)  and plasticity (the ability of the genotype to change phenotype dependent on the environment) of the individual.  Different mouse strains differ in coping strategies in stress situations, and these coping strategies  may be related to this balance. In this study, development of FA was studied in female mice of three different  inbred strains, 129s6/Sv, C57BL/6J, and BALB/c, during a 6 week period. Besides the comparison  of different strains, single housing was compared to group housing conditions. Overall, FA did not differ  between strains. After six weeks, single-housed mice had higher FA than those that were group housed  (P<0.001), which may indicate that single housing causes a higher degree of environmental stress than  group housing does.