Pedigree Analysis Practice Problems

Pedigree Anaylysis Practice Problems

The pedigree below illustrates a case of dominant epistasis. (a)What symbol represents the genotype A-B-? (b)What symbol represents the genotype aaB-? (c) What symbol represents the genotype aabb? (d) What type of epistasis would be represented if II2 × II3 produced, in addition to and , an offspring of type? (e)What type of interaction would be represented if III5 × III6 produced, in addition to and , an offspring of type ?

Given the following pedigree showing three generations of mink breeding,where open symbols represent wild type and solid symbols represent platinum, determine (a) the mode of inheritance of these coat colors, (b) the most probable genotypes of all individuals in the pedigree (use of familiar symbols such as A, a and B, b are suitable), (c) what phenotypic proportions are expected in progeny from III1 × III2.

The pedigree below shows the genetic transmission of feather color in chickens. Open symbols represent white feathers, solid symbols represent colored feathers. Under the assumption of dominant and recessive interaction (given A- or bb or both = white, aaB- = color), assign genotypes to each individual in the pedigree. Indicate by (-) whatever genes cannot be determined.

Additional practice problems for these concepts can be found at:

• Genetic Interactions Practice Problems
• Genetic Interactions Practice Test