AP BIOLOGY

Detailed explanation-1: -Definition. A polygenic trait is a characteristic, such as height or skin color, that is influenced by two or more genes. Because multiple genes are involved, polygenic traits do not follow the patterns of Mendelian inheritance . Many polygenic traits are also influenced by the environment and are called multifactorial.

Detailed explanation-2: -Polygenic trait refers to a trait that is controlled by multiple non-allelic genes. These genes are called polygenes. They are a group of genes that, when turned on, are expressed as a unit. Each of them produces an effect that adds up to the trait.

Detailed explanation-3: -In polygenic inheritance, a particular character is controlled by three different genes. In general, phenotypic ratio is 1:6:15:20:15:6:1 instead of 27:9:9:9:3:3:3:1 in second filial generation. Here, the genotype of parents is AaBbCc and AaBbCc. Gametes formed are ABC, ABc, Abc, abc, aBC, aBc, abC, AbC.

Detailed explanation-4: -So, the correct option is ‘Polygenic trait is controlled by multiple alleles’.

Detailed explanation-5: -Polygenic inheritance refers to the inheritance of a trait governed by more than one genes. Generally, three or more genes govern the inheritance of polygenic traits. Multiple independent genes have an additive or similar effect on a single quantitative trait.