Cross a homozygous running heterozygous black mouse with a w

Cross a homozygous running, heterozygous black mouse with a waltzing brown mouse. What is the probable phenotype ratio? Show punnet square and all work.

Solution

Dihybrid cross

Homozygous running & heterozygous black -mouse         x    heterozygous black & waltzing mouse

Parental gametes --> RRBb                             x                       rrbb

              RB        Rb         RB         Rb

rb     RrBb        Rrbb     RrBb           Rabb

rb      RrBb      Rrbb       RrBb         Rrbb

rb      RrBb      Rrbb       RrBb           Rrbb

rb    RrBb      Rrbb       RrBb           Rrbb

F1-phenotypes

Running black mouse

Running brown mouse