variant strain of mice that is formed by backcrossing to an inbred parental strain for ten or more generations while maintaining heterozygosity at a selected locus (see Chapter 3). See Congenic in the MGI Glossary.
a strain of animals that is formed by backcrossing to an inbred parental strain for ten or more generations while maintaining heterozygosity at a selected locus. Resulting strains are assumed to differ only at this small heterozygous chromosomal region. [Source: Source: NHBLI/NCBI Glossary
Nearly identical strains of an organism; they vary at only a single locus.
Animals which are genetically constructed to differ at one particular locus.
In genetics, two organisms that differ in one locus are defined as congenic.