polygenic inheritance - lqc 8a

Question 1

polygenic inheritance

Answer 1

More than one gene for a single characteristic, with each gene at a different locus. Genes interact with each other, and have additive effects. Polygenic inheritance contributes to continuous variation.

Question 2

How do polygenic inheritance and the environment lead to continuous variation within a phenotype?

Answer 2

Many genes are involved at more than one locus and each gene has a small effect. The genes interact and the additive effect of the alleles of many genes produces many different genotypes (the more genes involved, the greater the number of genotypes). The effects of the environment may cause even more variation, resulting in a continuous range of phenotypes with many intermediates

Question 3

Which conditions/diseases arise where the alleles may confer a susceptibility, but environmental factors also contribute to the condition?

Answer 3

Diabetes, coronary heart disease, Alzheimer’s disease, schizophrenia and some cancers