Construction of a set of RI strains from B6 and DBA progenitors

A single pair of chromosome homologs are followed through the process of RI strain development. Genomic intervals derived from B6 are indicated by shading and intervals derived from DBA are indicated without shading for all genotypes in all generations. The map positions of five fictitious loci, numbered 1-5, are shown in the progenitor generation. In the F2 generation, the genotypes at these five loci are indicated for six different animals with "B" signifying the B6 allele and "D" signifying the DBA allele. The two circled regions represent segments of the genome that are already fixed for one parental type within the two F2 progenitors of particular incipient RI strains. At the F20 generation, four separate animals with the same homozygous genotype are shown for each of the three newly constructed RI strains (fictitiously called BXD-101, BXD-102, and BXD-103).