True breeding: a true breeding strainplugin-autotooltip__default plugin-autotooltip_bigStrain or line: refers to a pool or colony of individuals or cultured cells of a desired genotype or phenotype that is mostly homogeneous and can be bred and/or produced in perpetuity for research or commercial purposes. “Strain” tends to be used more for microorganisms and is one that has been inbred for multiple generations. We assume that the vast majority of lociplugin-autotooltip__default plugin-autotooltip_bigLocus (plural form: loci): a physical location of a gene; often used as a synonym for a gene. are homozygousplugin-autotooltip__default plugin-autotooltip_bigHomozygous: a state for a diploid organism wherein the two alleles for a gene are identical to each other. in a true breeding strainplugin-autotooltip__default plugin-autotooltip_bigStrain or line: refers to a pool or colony of individuals or cultured cells of a desired genotype or phenotype that is mostly homogeneous and can be bred and/or produced in perpetuity for research or commercial purposes. “Strain” tends to be used more for microorganisms and.