Biology 3338A/B Lecture Notes - Lecture 5: Archenteron, Delamination, Triploblasty

57. In a specific cross, F2 progeny exhibit a modified dihybrid ratio of 9 : 6 : 1 (instead of 9 : 3 : 3 : 1).

What phenotypic ratio would be expected from a test-cross with one of the F1 progeny?

A. 1 : 3 : 1 B. 1 : 2 : 1 C. 1 : 1 : 1 D. 2 : 1 : 1 E. 3 : 1 : 1

For the cross AAbb x AaBb, what is the phenotype ratio? (answermust be four numbers seperated by colons)

A_B_: aaB_ : A_bb : aabb = _________

(ANSWERS ARE NOT: 9:3:3:1, 1:1:1:1, 1:1,4:4:4:4)

genotype ratio: 1:1:1:1

progenies: AaBb, AAbb, Aabb, AABb

In the cross between two RrTtYy plants, what is the expected frequency of offspring

a. 1/32 b. 1/8 c. 1 d. 1/16

with the same genotype as the parents (i.e., RrTtYy)?

a. 1/2 b. 1/16 c. ¼ d. 1/8 e. 0 f. 1/64 g. 1 h. 1/32