Question

The following numbers of offspring were observed in two separate dihybrid crosses between an F₁ hybrid and a double (recessive) mutant.

1st cross:   2nd cross:

w⁺w b⁺b x ww bb pr⁺pr vg⁺vg x prpr vgvg

w⁺w b⁺b ww bb w⁺w bb ww b⁺b pr⁺pr vg⁺vg prpr vgvg pr⁺pr vgvg prpr vg⁺vg

800 800 200 200 600 600 400 400

Which pair of genes are linked, and which pair of genes are closer together on the same chromosome?

Group of answer choices

a) both pairs are linked, w gene is closer to b than pr is to vg

b) only w and be genes are linked, they are closer together

c) only pr and vg genes are are linked' they are closer together

d) neither gene pair are linked; distances between genes does not apply in these two examples

Answer 1

Option A

In both the cases, the classical mendelian ratio (1:1:1:1) obtained in dihybrid cross is not obtained. So both the genes in both the cases will be linked to each other.

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