Dihybrid inheritance, multiple alleles and sex linkage Quiz

1. How many different gametes are produced by a plant with genotype $AaBb$ (genes on different chromosomes)?

• A. 2
• B. 4
• C. 8
• D. 16

2. Which genotype gives blood group B?

• A. $I^AI^B$
• B. $I^OI^O$
• C. $I^BI^O$ only
• D. $I^BI^B$ or $I^BI^O$

3. Out of 320 offspring from $AaBb$ × $AaBb$, how many are expected to be double recessive?

• A. 20
• B. 40
• C. 60
• D. 180

4. A woman who is a carrier of haemophilia and a man with normal clotting have a son. What is the chance he has haemophilia?

• A. 0
• B. 1/4
• C. 1/2
• D. 1

5. Why can a man not pass an X-linked allele to his son?

• A. The son receives only the father's Y chromosome from him
• B. The allele is lost in meiosis
• C. X-linked alleles are always recessive
• D. The allele is on the Y chromosome