What does a one-factor Punnett square analyze?

• A. The inheritance of only one trait.
• B. The inheritance of two traits at the same time.
• C. The interaction between genes and environment.
• D. The rate of mutation for a single gene.

Answer: (A)

A one-factor Punnett square analyzes the inheritance of a single trait by looking at one gene locus with two alleles and predicting the probabilities of offspring genotypes and phenotypes for that trait. It shows how the alleles combine from two parents to produce the possible offspring, typically illustrating Mendelian patterns such as a 3:1 phenotypic ratio when one allele is dominant and both parents are heterozygous. This is focused on one trait at a time and does not address how two traits might interact (that would require a dihybrid cross), nor does it account for environmental effects or mutation rates.