Question

The percentage of 'ab' genotype gametes produced by ‘AaBb’ parent plant is:

• A. 50
• B. 25
• C. 12.5
• D. 75

Hint:

When considering a dihybrid cross like AaBb, the possible gametes are the combinations of the alleles for each gene. The percentage of a particular genotype can be calculated by counting the number of favorable combinations.

Answer 1

The Correct Option is B

In a cross of AaBb (where both genes show dominant and recessive alleles), we want to find the percentage of gametes that have the ab genotype. First, let’s consider the gametes that the AaBb parent will produce. The possible gametes from this cross are determined by the law of independent assortment, which gives the following combinations:
- AB
- Ab
- aB
- ab Now, out of these four gametes, only ab contains both the recessive alleles for both genes. Thus, the percentage of ab genotype gametes produced is: \[ \text{Percentage of ab gametes} = \frac{1}{4} = 25\% \] Therefore, the correct answer is 25%.