Epistasis ratios with examples

EPISTASIS 

*Epistasis is the interaction between different genes

*If one allele or allelic pair masks the expression of an allele at the second gene, that allele or allelic pair is epistatic to the second gene

eg : Kernel color in wheat , Flower color in sweet pea

Various epistatic ratios and their examples

Gene interaction/epistasis	Ratio	Examples
Typical dihybrid ratio	9:3:3:1	Comb shape in poultry
Recessive epistasis / supplementary epistasis	9:3:4	Grain color in Maize , Coat color in mice
Duplicate recessive epistasis / complementary epistasis	9:7	Flower color in sweet pea , HCN production in clovers
Dominant epistasis/simple epistasis	12:3:1	Fruit color in summer squash
Duplicate dominant epistasis / Duplicate gene interaction	15:1	Awn character in rice
Polymeric gene interaction	9:6:1	Fruit shape in summer squash
Inhibitory epistasis	13:3	Anthocyanin pigmentation in rice , Feather color in poultry