AP BIOLOGY

Detailed explanation-1: -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: -Some traits are controlled by genes that pass from parent to child. Others are acquired through learning. But most are influenced by a combination of genes and environmental factors.

Detailed explanation-3: -Each chromosome contains thousands of individual genes. There are thought to be about 20, 000 genes in human DNA. Interestingly, the number of genes in human DNA is not appreciably different from the number of genes in chimpanzees or mice. Most traits are determined by more than one gene.

Detailed explanation-4: -Single-gene traits include some of the most observable physical traits in humans, like eye color, widow’s peak hairline, earlobe type (attached versus detached), presence of freckles or dimples, or the ability to roll your tongue.