If an organism is heterozygous for three genes, what formula determines the number of gametes produced?

• A. # of genes x # of alleles
• B. # of alleles ^ # of genes
• C. # of genes + # of alleles
• D. # of alleles - # of genes

Answer: (B)

The correct choice is rooted in the principles of genetics, specifically how alleles segregate during gamete formation. When an organism is heterozygous for three genes, it has two different alleles at each gene locus.

To determine the number of distinct gametes that can be produced, you utilize the formula that accounts for the different combinations of alleles. Since each gene can contribute two possible alleles (due to being heterozygous), and there are three such genes, the possible combinations are calculated by raising the number of alleles to the power of the number of genes.

In this case, with two alleles per gene and three genes, the calculation becomes:

Number of gametes = (Number of alleles per gene) ^ (Number of genes) = 2^3

This equates to 2 x 2 x 2, resulting in eight unique gametes. This principle highlights the way genetic variation is achieved through sexual reproduction, as the different combinations of alleles from each parent can lead to diverse offspring.