Monohybrid cross in mice

    A coat colour locus (B) 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 combination, BB, Bb , bB, and bb, at equal frequencies, of which three (BB, Bb, and bB) produce black offspring due to the dominance of B to b, and one (bb) produces a brown offspring. 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 ©2014 by Steven M. Carr