HMB 265 Forms of Epistasia and Complementation

Reciprocal recessive epistasis

Reciprocal recessive epistasis - biochemical explanation

Tldr need two copies of the dominant allele to deposit pigment/see wt phenotype

Reciprocal dominant epistasis

Reciprocal dominant epistasis biochemical explanation

Tldr the dominat alleles of the gene code for a protein with the same ability to produce the wild type phenotype

Recessive epistasis

Recessive epistasis biochemial pathway

Homozygous recessive allele at one locus hides the effect of the other locus

Bombay phenotype

All type A, type AB, type B, and type O people are H— People with hh genotype will appe

ar to be type O regardless of their I locus genotype Gene for substance H is epistatic to the I gene (hh is epistatic to all combinations of I alleles, except for ii)

Dominant epistasis I

Dominant epistasis I biochemical pathway

Dominant allele of one locus hides both alleles of other locus e.g. summer squash colour. Genotype B- masks the effect of all A- genotypesB is epistatic to A and a

Dominant epistasis II

Dominant epistasis II biochemical pathway

Dominant allele of one locus hides dominant allele of other locus e.g. chicken feather colour

Genotype B masks the effect of all A- genotypes B is epistatic to A