Part 2: Dihybrid Crosses
1. In Labrador Retrievers, coat color is controlled by two genes. One gene controls which pigment the hair
follicle produces. Black pigment (B) is dominant over brown pigment (b). A second gene controls whether
pigment gets deposited in the hair. Pigment deposited (D) is dominant over pigment not being deposited
(d). When pigment is not deposited, the Labrador's coat will be yellow.
a. What is this type of inheritance pattern called?
b.
Fill in all possible gametes for a F, Labrador.
C.
Write out a dihybrid cross for coat color between two F, individuals and give the phenotypic ratios. Be
sure to indicate which outcomes go with each number in your ratio.