Color Blindness Problem Set

Problem 3: Barbara's genotype

Audrei is the family member who contacted us. She has a red-green color perception defect. Her father is also color blind, but her mother Barbara is not. What is Barbara's genotype? Remember that Audrei's mother does not have a color perception defect.

You answered: C. homozygous recessive for the red-green color blind allele

If Barbara, the mother, were homozygous recessive for the red-green color blind allele she would be color blind. Audrei's mother has normal vision.

Female Genotype	Female Phenotype
X^R X^R	Normal Vision
X^R X^r	Normal vision, "carrier"
X^r X^r	Red-green color blind

The Biology Project
University of Arizona
Saturday, October 10, 1998
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