Inheritance Patterns

Additive

4 distinct F2 phenotypes

9:3:3:1

Recessive Epistasis

Homozygous recessive allele of one gene mask both alleles of another gene

9:3:4

Reciprocal recessive epistasis

Homozygous recessive allele of each gene masks the dominant allele of other gene

9:7

Dominant epistasis I

Dominant allele of one gene hides effects of both alleles of the other gene

12:3:1

Dominant epistasis II

Dominant allele of one gene hides effects of dominant allele of other gene

13:3

Redundancy

Only one dominant allele of either 2 genes is necessary to produce phenotype

15:1

Complete Dominance

3:1

Incomplete Dominance

Mixing of 2 alleles

1:2:1

Codominance

Both alleles appear

1:2:1

Recessive Lethal

Homozygous allele dies during development

2:1

Multiple alleles

Most genes exist in more than 2 forms

Pleiotropy

1 gene affects multiple genes