Gregor Mendel is the 19th Century Augustinian Friar credited with the discovery of modern genetics. In Genotype, you play as his assistants, competing to collect experimental data on pea plants by trying to control how the plants inherit key Traits from their parents: seed shape, flower color, stem color, and plant height. The observable Traits of a Pea Plant (its Phenotype) are determined by its genetic makeup (its Genotype). The relationship between Genotype and Phenotype and the nature of genetic inheritance are at the heart of Genotype: A Mendelian Genetics Game.

During the game, players get Pea Plant Cards which show a set of Phenotype Traits they hope to produce and collect (such as pink flowers and tall height) in order to score points. Each round, Dice are rolled to represent Plant breeding, which may result in the Traits players are looking for