WILD MOUSE & LABORATORY MOUSE HISTORICAL ASPECTS, GENETIC SELECTION AND WELFARE

The mouse is the most used animal model in biomedical pre clinical trials. Its phylogeny descends from the genus Mus , subgenus Mus and species Mus musculus . The origin of this animal as an experimental model is due to the capture of wild subspecies mainly Mus musculus domesticus , Mus musculus musculus , Mus musculus castaneus and the hybrid subspecie Mus musculus molosinus . For centuries, diverse breeders with diverse geographical locations have been breeding and swapping selected individuals from among them, which has promoted very large genetic variability and difficulty in accurately recording subspecies that gave rise to both isogenic strains and outbred stocks individuals. The couple Abbie Lathrop and Leo Loeb in Massachusetts (United States of America) are the most cited in this activity. But it was documented, mainly at the origin of the inbred lineages, however, Swiss outbred stock that other unknown suppliers were selecting albino mice and supplying to research institutes. Currently, we believe in the theory of the subspecies Mus musculus laboratorius existence in house facilities. Because through years suffering artificial evolutionary and selective pressures the extreme adaptability of this animal (which made it possible to be captured in the wild and reproduce in captivity) also made the restriction of space in the laboratory enviroment. However, we must take into consideration, with great respect for this animal, that despite its adaptability, its welfare is linked to the expression of its intrinsic natural behavior to the species M. musculus . Thus we have the obligation to provide mating and management directed at reducing the aggressiveness of adult males; searching for equipment and materials to the mouse preference; avoiding abrupt changes in environment and routine and proper handling. Thus, the genealogical and phylogenetic study of this species can contribute to the welfare of laboratory mouse and during the important knowledge discovered during their use, breeding and animal testing.