What is the purpose of a Punnett square?

The purpose of a Punnett square is to predict the genetic outcomes of crosses between individuals with specific genotypes. This tool allows students and researchers to visualize how alleles from each parent can combine in the offspring. By arranging potential gametes from each parent along the axes of the square, one can systematically calculate the probabilities of various genotype combinations that may result from the mating.

For instance, when two heterozygous individuals are crossed, the Punnett square will show the proportion of offspring expected to exhibit each genotype, along with the associated phenotypes. This method is invaluable in genetics for understanding inheritance patterns, especially when exploring traits governed by Mendelian genetics.

Understanding how alleles interact helps clarify broader topics in genetics, such as dominance and recessiveness, but the main focus of the Punnett square is on predicting outcomes rather than solely identifying dominant traits or phenotypes, or illustrating environmental effects.