Gregor Mendel, who was known as the "Father of Genetics", was inspired by his teachers and colleagues in monastery to study variation in plants. He conducted pea plant experiment between 1856 to 1863 and established many of the rules of heredity.

Mendel used garden peas for his experiment because it has both stamen and carpel, it is also easy to take care, it can produce many offspring in a short period of time and especially it has many paired characteristics. He worked with seven characteristics of pea plants and those are: plant height, pod shape and color, seed shape ad color, and flower position and color. He first focused on seed shape, which was either angular or round. With the seeds color he showed that when green and yellow pea plants are breed together their offspring will always be yellow. 

However, in the next generation of plants, he allowed the hybrid plants to self-pollinate and the green peas reappeared. Mendel described each of the trait variants as recessive and dominant. He did thousands of cross breeding experiments. His key finding was that there were 3 times as many dominant as recessive traits in pea plants (3:1 ratio)

Mendel also used punnet square for him to be able to predict the possible gene combination of the parents who are unknown. This includes the recessive and dominant in reference to certain traits.