Recombinant congenic breeding scheme

Recombinant congenic (RC) breeding scheme. Donor strain genetic material is shown in white and recipient genetic material is shown in black. There are two stages in the RC breeding program. The behavior of a schematic autosome pair is depicted during each of these stages. Stage 1 consists of repeated backcrosses to the recipient strain, so as to reduce the donor contribution to the genotype. There is no selection for donor alleles. Stage 2 occurs as independent sib-pairs from the second backcross generation are used to establish new inbred strains, with full-sib matings at each generation. Inbreeding fixes the genotype of the strain, with most loci becoming homozygous by the 12th generation. The resulting array of genotypes is shown schematically at the bottom of the figure. Only one copy of the schematic autosome from each strain in the set is shown. The donor contributions in each strain in the set are map loci contributing to continuously varying traits and eliminates the need for genotyping to achieve the resolution achieved by quantitative trait loci (QTL) quantitatively similar, but the specific chromosome regions of donor genotype will differ from one strain to another.