Problem 1: Dalmatian dogs occur in two colors - normal black spots and bown (liver) spots. Assume that the black-spotted condition is dominant over the brown-spotted condition. Please determine the following:
a) The letters you would use to identify the alleles for a black-spotted dog and the alleles for a brown-spotted dog.
b) Using a Punnet Square cross a homozygous black-spotted dog with a homozygous brown-spotted dog and provide the following information:
Problem 2: In addition to the color of spots, assume that brown eyes are dominant over blue eyes.
a) The letters you would use to identify the alleles for a homozygous black spotted brown-eyed dog and the alleles for dog that is heterozygous for black spots and homozygous for blue eyes.
b) Using a Punnet Square cross a homozygous black-spotted and brown-eyed dog with a heterozygous black-spotted blue-eyed dog and provide the following information:
1. The phenotypes (color of spots and eyes) that result.
2. The percentage of each phenotype produced.
3. The genotypes that result.
4. The percentage of each genotype produced.
Explanation and solutions to two genetics problems involving the use of Punnett squares with dihybrid crosses.
Breeding Dihybrid Crosses
In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If two dihybrids (Bb Ss) were crossed, which would be produced?
A. black and spotted pure-breeding forms
B. black and solid pure-breeding forms
C. red and solid pure-breeding forms
D. red and spotted pure-breeding forms
E. all of these