In genetics, what do the letters in a Punnett square represent?

The letters in a Punnett square represent the possible genotypes of offspring that can result from the combination of alleles from the parents. When constructing a Punnett square, the alleles contributed by each parent are placed along the top and side of the square. By filling in the boxes, one can visualize all the genetic combinations that could arise in the offspring based on the alleles present in the parents.

Each box in the Punnett square reflects a different genotype that the offspring might inherit. This tool is particularly useful in predicting traits based on Mendelian inheritance patterns, where allele combinations determine phenotypic expression. Thus, the representation of potential genotypes in a Punnett square is fundamental to understanding inheritance and genetic variation among progeny.