All the strains will be genotyped to verify that they are homozygous at each position of the genome. This is illustrated above for the strain “Archer_EH”, kindly genotyped by Dr Fernando Pardo-Manuel de Villena and colleagues (UNC). Chromosome regions inherited from the founder strains are shown in different colours. This strain is not yet inbred as seen by regions of residual heterozygosity.

By sib-mating of the G3, and successive sib-mating of their progeny, inbred strains are derived from each original mating line. The usual number of inbreeding generations required is 20.

 

Each of the strains of The Collaborative Cross will have a different mosaic of chromosomal regions inherited from the founder strains.