Genetic inheritance

Hardy-Weinberg Analysis

Codominance

both alleles contribute to the phenotype of the heterozygote

E.g Blood groups; alpha1-antitrypsin deficiency

Variable expressivity

phenotype varies among individuals with same genotype

Eg. 2 pts with NF may have varying disease severity

Pleiotropy

This occurs when one gene controls many traits in an individual.

The occurence of multiple phenotypic manifestations, often in different organ systems, as a result of a single genetic defect.

E.g untreated PKU manifests w/ light skin, intellectual disability, and musty body odor

Locus heterogenecity

mutations at different loci can produce a similar phenotype

E.g Albinism

Allelic heterogenecity

Different mutations in the same locus produce the same phenotype

E.g Beta-thalassemia

Loss of heterozygosity