Single gene traits are mainly controlled by a single gene, while polygenic traits are those traits influenced by many genes (Larsen, 2019). Single gene traits show a distinct phenotype as the phenotypic expression is according to the Mendelian inheritance, where we can observe two distinctive phenotypic expressions. Common examples of the single gene trait are tongue rolling ability, earlobe type, and freckle presence. One person can only show one phenotype. For example, the tongue rolling ability can be present in the person or not, and the earlobe would be either attached or free. In the same way, the dimple would be present or absent in the person.