Topic 13 pt 2: Gene Interaction

Question 1

Types of epistasis

Answer 1

Recessive epistasis
Dominant epistasis
Duplicate recessive epistasis
Duplicate dominant epistasis

Question 2

Ratios for F2 in types of epistasis

Answer 2

Rec epi = 9:3:4
Dom epi = 12:3:1
Dup rec epi = 9:7
Dup dom epi = 15:1

Question 3

Example of recessive epistasis (explain), ratio in F2

Answer 3

Labrador retriever coat colour, “ee” is epistatic over the B locus (determines black or brown)
9:3:4

Question 4

Example of dominant epistasis (explain), ratio in F2

Answer 4

Colour in squash, big W leads to white colour in all cases)
12:3:1

Question 5

Example of duplicate recessive epistasis (explain), ratio in F2

Answer 5

Snail pigmentation, having either aa OR bb leads to albino snail
9:7

Question 6

Example of duplicate dominant epistasis (explain), ratio in F2

Answer 6

Locus T in capsella bursa-pastoris, having large T or V will lead to heart shape
15:1

Question 7

Look at all slides and examples at end!!

Answer 7

Important