Name:______

Period:______

Genetic Problems: Night 2

Monohybrid, Dihybrid, and Test Crosses

Directions: Show your Work! You can use the back for scratch work, if you need to uses scratch paper, attach it. Work must be shown to receive full credit!!!!

  1. Two plants having red flowers are mated. When their F1 offspring are studied, it is found that 95 have red flowers and 31 have white flowers. What is the genotype of the parents and diagram a cross to support your answer.
  1. Ingarden peas, axial flower position is dominant and terminal flower position is recessive, tall vine is dominant and short vine is recessive. A plant known to be purebred for tall vine and axial flowers is crossed with a plant having shortvines and bearing terminal flowers

A)What is the phenotype of the offspring?

B)What is the genotype of the offspring?

C)Predict the types of offspring ( their phenotypes) that wourld appear in the F2 generation and their ratios.

  1. In horses, black is a dominant trait (B), chestnut is recessive (b). The trotting gait is dominant (T), pacing is recessive (t).

A)If a homozygous black pacer is mated to a homozygous chestnut trotter, what will be the appearance of the F1 generation?

B)If two F1 individuals were mated, what types of offspring could they have and in what ratios?

  1. In dogs, wire hair is a dominant trait, smooth hair is recessive. Two wire-haired dogs produce a male puppy that is were-haired. To find out most quickly whether he carries the allele for smooth hair, he should be mated to what type of female?
  1. In a certain animal, a breed is known that always has a hairy tail; another breed is known that always has a naked tail. How would you determine which trait is dominant?
  1. In cocker spaniels, black is a dominant trait (B), red is recessive (b). solid color is dominant (S). white spotting is recessive (s). A red male was mated to a black-and-white females. They had five puppies, as follows: 1 black, 1 red, 1 black-and-white, and 2 red-and-white. What were the genotypes of the parents?
  1. In sheep, white coat is dominant and black is recessive. Occasionally, a black sheep appears in a flock. Black wool is worthless. How could a sheep farmer eliminate the genes for black coat from the flock?
  1. In laboratory mice, the normal gray color is dominant over the albino (all-white) color. Starting with a purebred albino and a purebred gray as parents, what is the ratio of phenotypes in the F2 generation?