Monohybrid inheritance and sex linkage Quiz

1. What is a heterozygous individual?

• A. Someone with two identical alleles
• B. Someone with one allele only
• C. Someone with two copies of the dominant allele
• D. Someone with two different alleles of the same gene

2. Two carriers of a recessive autosomal condition have a child. What is the probability that the child is affected?

• A. 0%
• B. 25%
• C. 50%
• D. 75%

3. A colour-blind man ($X^{b}Y$) has children with a woman with normal vision who is $X^{B}X^{B}$. What proportion of their sons are colour blind?

• A. All of them
• B. Half of them
• C. None of them
• D. A quarter of them

4. Two roan cattle ($C^{R}C^{W}$) are crossed. What is the ratio of red : roan : white calves?

• A. 1 : 2 : 1
• B. 3 : 1
• C. 1 : 1
• D. 2 : 1 : 1

5. In a pedigree, two unaffected parents have an affected child. The condition must be:

• A. Dominant
• B. Recessive
• C. Y-linked
• D. Codominant