Question

In a rabbit farm, grey coloured fur (GG) is dominent over white fur (gg) and black eye (BB) is dominent over red eye (bb). A pure breeding grey coloured black eyed male rabbit was crossed with a pure breeding white coloured red eyed female. What are the phenotypes of the offspring obtained in F1 generation. Find the phenotype raatio in the F2 generation.

Answer 1

Answer:

F1 has GgBb i.e., grey colored black eye rabbit

F2 has 9:3:3:1 phenotypic ratio

Answer 2

The phenotypes of the F1 offspring is : Grey and Black.

The phenotypic ratio of the F2 generation is :

9 : 3 : 3 : 1.

Explanation:

• The genotypes of the pure breeding individuals are:

1. Grey coloured black eyed - GGBB. (Male)
2. White coloured red eyed - ggbb. (Female)

• The gametes produced by the above parents are - GB and gb.
• The F1 offspring will have, Genotype - GgBb and Phenotype - Grey and Black.
• F1 offspring will produce the following gametes : GB, Gb, gB, gb.
• Mating F1 offspring with each other will generate the following progenies:

                               GB         Gb            gB             gb

                  GB     GGBB     GGBb      GGBb       GgBb

                             G/B          G/B          G/B           G/B

                  Gb     GGBb     GGbb       GgBb        Ggbb

                              G/B        G/R           G/B           G/R

                   gB     GgBB     GgBb       ggBB         ggBb

                               G/B       G/B           W/B           W/B

                   gb      GgBb    Ggbb        ggBb         ggbb

                               G/B        G/R          W/B           W/R

• In the above cross, G - Grey colour fur, B - Black eye, W - White colour fur and R - Red eye.
• The phenotypes of F2 progenies :

1. Grey fur and Black eye -  9.
2. Grey fur and Red eye - 3.
3. White fur and Black eye - 3.
4. White fur and Red eye - 1.