Finding evidence of genetic linkage

 

Three dominant traits of corn seedlings, tunicate seed (T -), glossy appearance (G -), and liguled stem (L -), are studied along with their recessive counterparts, nontunicate (tt), nonglossy (gg), and liguleless (ll). A trihybrid plant with the three dominant traits is crossed to a nontunicate, nonglossy, liguleless plant. Kernels on ears of progeny plants are scored for the traits, with the following results:

 

Phenotype	Number
Tunicate, glossy, liguled	102
Tunicate, glossy, liguleless	106
Tunicate, nonglossy, liguled	18
Tunicate, nonglossy, liguleless	20
Nontunicate, glossy, liguled	22
Nontunicate, glossy, liguleless	23
Nontunicate, nonglossy, liguled	99
Nontunicate, nonglossy, liguleless	110
	500

1. Is there evidence of genetic linkage among any of these gene pairs?

A) Yes, there is evidence.

B) No, there is not any evidence.

2. Is there evidence of independent assortment among any of these gene pairs?

A) Yes, there is evidence.

B) No, there is not any evidence.

3. Select the genotype of the F1 trihybrid plant:

A) Tg/tG; Ll

B) TG/tg; Ll

4. Using the gene symbols given above, choose the genotypes of F2 plants.

Sort the items below into the following categories: (1) TG/tgLl, (2) TG/tgll, (3) Tg/tgLl, (4) Tg/tgll, (5) tG/tgLl, (6) tG/tgll, (7) tg/tgLl, (8) tg/tgll.

A) Tunicate, nonglossy, liguled

B) Nontunicate, glossy, liguled

C) Nontunicate, glossy, liguless

D) Nontunicate, nonglossy, liguleless

E) Tunicate, glossy, liguled

F) Nontunicate, nonglossy, liguled

G) Tunicate, nonglossy, liguleless

H) Tunicate, glossy, liguleless