Which statement about Punnett Squares is true?

• A. They always show actual results
• B. They do not show actual results
• C. They are only applicable to asexual reproduction
• D. They are used to measure population allele frequencies

Answer: (B)

Punnett squares show the potential genotypes and their probabilities for offspring from a cross, not the actual results of a real mating. They lay out all possible allele combinations that could appear in the next generation based on the parents’ alleles, but they describe likelihoods rather than guarantee what will happen in a single family. In other words, you’re looking at a model of possible outcomes and how often they should occur on average, assuming random fertilization and Mendelian segregation. A real cross can yield different results due to random sampling, especially with few offspring, though many offspring tend to match the predicted proportions.

These squares are built for sexual reproduction because each parent contributes one allele, whereas they don’t apply to asexual reproduction. They also don’t measure allele frequencies in a population directly; to know how common an allele is in a population, you’d sample many individuals and calculate frequencies, rather than infer them from a single cross’s predicted outcomes.