Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 20

In chickens, some varieties have feathered shanks (legs), but others do not. In a cross between a Black Langhans (feathered shanks) and Buff Rocks (unfeathered shanks), the shanks of the F 1 generation are all feathered. When members of the F 1 generation are crossed to each other, the F 2 generation contains chickens with feathered shanks to unfeathered shanks in a ratio of 15:1. Suggest an explanation for this result.