If a colourblind man marries a woman who is homozygous for normal color vision, the probability of their son being colourblind is:
Correct answer: A. 0
- A. 0
- B. 0.5
- C. 0.75
- D. 1
Explanation
Color blindness is X-linked recessive. A homozygous normal mother (XX) cannot pass the mutant X; sons get father's Y and mother's normal X so 0% affected sons.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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