Figure 1. Illustration of the breeding scheme used in the mapping cross. The BALB/cByJ and C57BL/6ByJ parental strains are crossed in both directions. The resulting F₁ mice are inbred through brother–sister mating to produce the F₂ generation. This figure shows the manner in which the Y chromosomes and recombined (black and white-striped) and unrecombined (solid color) X chromosomes are passed through the generations of the cross. White chromosomes are inherited from the BALB/cByJ albino parent, and black chromosomes are inherited from the C57BL/6ByJ pigmented parent. The different coat colors shown in the F₂ generation are for illustrative purposes only. The color of the F₂ animals is unrelated to either gender or the direction of the cross.