Conplastic strains are strains in which the nuclear genome from one strain has been crossed onto the cytoplasm of another, i.e., the mitochondrial donor is always the female parent during the backcrossing program. The designation is NUCLEAR GENOME-mtCYTOPLASMIC GENOME. As with congenic strains, a minimum of 10 backcross generations is required, counting the F1 generation as generation 1. (http://www.informatics.jax.org/mgihome/nomen/strains.shtml)