Dihybrid Cross Analysis

How many different kinds of gametes will be produced by a plant having the genotype AABbCC?

1. Three

2. Four

3. Nine

4. Two

Two genes R and Y are located very close on the chromosomal linkage map of the maize plant. When RRYY and rryy genotypes are hybridized, then F₂ segregation will show:

1. higher number of the recombinant types

2. segregation in the expected 9:3:3:1 ratio

3. segregation in a 3:1 ratio

4. higher number of the parental types

Select the correct statement from the ones given below with respect to dihybrid cross:

1.	Tightly linked genes on the same chromosome show higher recombinations
2.	Genes far apart, on the same chromosome, show very few recombinations
3.	Genes loosely linked, on the same chromosome, show similar recombinations as the tightly linked ones
4.	Tightly linked genes on the same chromosome show very few recombinations

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A):	Mendel's law of Independent assortment does not hold good for the genes that are located closely on the same chromosome.
Reason (R):	Closely located genes assort independently.

In the light of the above statements, choose the correct answer from the options given below:

1.	(A) is False, (R) is True.
2.	Both (A) and (R) are True and (R) correctly explains (A).
3.	Both (A) and (R) are True and (R) does not correctly explain (A).
4.	(A) is True, (R) is False.

Genes R and Y follow independent assortment. If RRYY produce round yellow seed and rryy produce wrinkled green seeds, what will be then phenotypic ratio of the F₂ generation?
1. Phenotypic ratio - 9 : 3 : 3 : 1
2. Phenotypic ratio - 9 :7
3. Phenotypic ratio - 1 : 2 : 1
4. Phenotypic ratio - 3 : 1