Polygenic inheritance and variation

What is polygenic inheritance?

When a characteristic is influenced by multiple genes.

Are most phenotypic features controlled by a single gene?

No. Most are influenced by multiple genes, often alongside environmental factors.

What is variation?

Differences in characteristics between individuals of the same species.

What is genetic variation?

Differences between individuals caused by differences in their genetic information.

What causes genetic variation?

Mutations and sexual reproduction.

How does sexual reproduction cause genetic variation?

It combines genetic information from two parents, producing new combinations of alleles.

What is a mutation?

A change in DNA.

What is environmental variation?

Differences in characteristics caused by environmental influences.

What are examples of environmental influences on phenotype?

Diet, climate, exercise and exposure to sunlight.

What is an acquired characteristic?

A characteristic developed during an organism's lifetime due to environmental influences or experience.

What is continuous variation?

Variation with a continuous range of values, such as human height.

What is discontinuous variation?

Variation with distinct categories and no intermediate values, such as blood group.

What is an example of a characteristic influenced by both genes and the environment?

Human height, which is influenced by inherited alleles and factors such as nutrition.