Widespread over-expression of the X chromosome in sterile F1 hybrid mice

We used a reciprocal cross of Mus musculus and M. domesticus in which F1 males are sterile in one direction and fertile in the other direction, in order to associate expression differences with sterility. Four different crosses were performed. A cross between two strains within each mouse species (M. musculus, PWK/PhJ and CZECHII/EiJ; M. domesticus, LEWES/EiJ and WSB/EiJ). And two reciprocal crosses between a domesticus (LEWES/EiJ) and a musculus (PWK/PhJ) strain. The cross between a musculus female and a domesticus male produces sterile male offspring - whereas all other crosses produced fertile male offspring. Testis tissue from three male mice (60 days old) from all four crosses were analysed on the Affymetrix MG 430.2. Array.