Mechanisms of Natural Selection Maintaining in Groups of Highly Standardized Mice and Rats, Influence on Infection Resistance

Natural selection; i.e. mechanisms within animal collectives responsible for adaptation to altered environments is based on two main principles: (a) creation of individual variability and (b) elimination of particular individuals. Both principles — at least in part — persist in groups of highly standardized laboratory mice and rats. — The study reports on the maintainance of mechanisms creating inborn individual variability in inbred mice as well as on the persistance of sexual selection within groups of inbred male rats and the existence of three psychotypes within such animals. Finally the psychotype’s different susceptibility against an infection with Mycoplasma arthritidis is investigated.