Which term describes mutations obtained through breeding with inbred strains?

The term that describes mutations obtained through breeding with inbred strains is "congenic." Congenic strains are developed by introducing a mutation or a specific genetic variation into an inbred mouse strain. This is achieved by backcrossing animals that carry the mutation to a specific inbred background for several generations. This method allows researchers to study the effects of the mutation while controlling for the genetic background, essentially isolating the variable of interest.

The significance of congenic strains lies in their ability to provide a clearer understanding of the specific genetic alterations and their phenotypic consequences. By controlling for other genetic variations, scientists can more accurately attribute observed traits directly to the genes introduced through mutation.

The other terms listed—co-isogenic, transgenic, and hybrid—refer to different genetic concepts. Co-isogenic relates to strains that differ minimally at a specific locus but are genetically identical elsewhere; transgenic involves the introduction of foreign DNA into an organism; and hybrid typically refers to the offspring resulting from the mating of individuals from different species or strains, which does not specifically denote mutations acquired through inbreeding. Thus, the use of the term "congenic" accurately captures the precise genetic manipulation involved in obtaining mutations through inbred strains.