What is the purpose of a Punnett square?

The purpose of a Punnett square is to predict the genetic makeup of offspring from a particular genetic cross. This tool helps geneticists and biologists to visualize and calculate the probabilities of the different genotypes that can result from the combination of alleles contributed by the parents. By mapping out the alleles of each parent along the axes of the square, it allows for an organized approach to see all possible genetic combinations that their offspring could inherit.

In particular, it demonstrates Mendelian inheritance patterns, especially for traits that follow a simple dominant-recessive relationship. The resulting grid shows the ratio of potential genotypes and phenotypes among the offspring, making it a fundamental tool in genetics for forecasting heredity patterns. This application directly relates to the study of inheritance and genetic variation, ensuring that the predictions are based on established genetic principles.