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Dihybrid cross

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:

1. The phenotypes (color of spots) that result.
2. The percentage of each phenotype produced.
3. The genotypes that result.
4. The percentage of each genotype produced.

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.

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Solution Summary

Explanation and solutions to two genetics problems involving the use of Punnett squares with dihybrid crosses.

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