Monohybrid cross in mice

    In mice, a locus (B) at a particular point on a particular chromosome in mice influences black or brown fur. Each Bb parent produces equal numbers of B and b gametes. Random union of B and b gametes produces four possible combinations: BB, Bb , bB, and bb, at equal frequencies, of which three (BB, Bb, and bB) produce black offspring due to the dominance of the B allele to the b allele, and one (bb) produces a brown offspring by reinforcement of the b allele. Thus the mating of two heterozygous black mice produces the expected ratio of 3 black : 1 brown offspring.

Figure ©2002 by Griffiths et al;. all text material ©2016 by Steven M. Carr