17.7 - Epistasis Flashcards
What epistasis is An example of epistasis in coat colour genes in mice Biochemical pathways demonstrating epistasis Dominant and recessive epistasis
What is epistasis?
One gene affects or masks the expression of another
What is a hypostatic gene?
Gene whose expression is blocked
What is an epistatic gene?
Gene whose allele affects hypostatic gene expression
What does gene A control in mice coat color?
Banding pattern of black pigment
What does dominant allele A lead to?
Banded hairs
What does recessive homozygous genotype aa cause?
Solid black hairs
What does gene B control in mice coat color?
Melanin production
What does dominant allele B allow?
Melanin production
What does recessive genotype bb cause?
Blocks melanin production
What is the phenotypic ratio in the F2 generation of heterozygous agouti mice?
9:4:3 (agouti:albino:black)
How does epistasis occur in biochemical pathways?
Disruption of enzyme gene expression blocks pathway
What are the two types of epistasis?
Dominant and recessive
What is recessive epistasis?
Epistatic gene must be homozygous recessive
What is dominant epistasis?
Epistatic gene is dominant
