Question

Assignment: Using Punnett Squares Exploration

First Cross: Show a cross between a homozygous red bull (RR) and a heterozygous red cow (Rr).





















Genotypic ratio:
Phenotypic ratio:


Second Cross: Show a cross between a heterozygous red bull (Rr) and a heterozygous red cow (Rr).





















Genotypic ratio:
Phenotypic ratio:

Third Cross: Show a cross between a homozygous white bull (rr) and a homozygous white cow (rr).





















Genotypic ratio:
Phenotypic ratio:

Answer 1

Step-by-step explanation:

Genotype 1:

2/4 is RR so RR is 50%

2/4 is Rr so Rr is 50%

Phenotype:

Not enough info for that

Genotype 2:

1/4 is RR so RR is 25%

2/4 is Rr so Rr is 50%

1/4 is rr so rr is 25%

Phenotype:

?

Genotype 3:

4/4 is rr so rr is 100%

Phenotype:

??

Answer 2

Case I

Genotypic Ratio – RR: Rr = 2: 2 = 1: 1

Phenotypic Ratio – All the offspring are red in color as R is dominant over r

Case II

Genotypic Ratio – RR: Rr: rr = 1: 2: 1

Phenotypic Ratio – All RR and Rr are red in color while rr is of different color, thus the phenotypic ratio is Red offspring : White offspring = 3:1

Case III

Genotypic Ratio – All offspring’s are of genotpe rr

Phenotypic Ratio – All offsprings are of white color

Step-by-step explanation:

Case I – Homozygous red bull (RR) and a heterozygous red cow (Rr)

(R ) is dominant over ( r )

The punnet square for the cross between the Homozygous red bull (RR) and heterozygous red cow (Rr) is as follows -

R R

R RR RR

r Rr Rr

Genotypic Ratio – RR: Rr = 2: 2 = 1: 1

Phenotypic Ratio – All the offspring are red in color as R is dominant over r

Case II - heterozygous red bull (Rr) and a heterozygous red cow (Rr)

The punnet square for the cross between the heterozygous red bull (Rr) and a heterozygous red cow (Rr) is as follows -

R r

R RR Rr

r Rr rr

Genotypic Ratio – RR: Rr: rr = 1: 2: 1

Phenotypic Ratio – All RR and Rr are red in color while rr is of different color, thus the phenotypic ratio is Red offspring : White offspring = 3:1

Case III - homozygous white bull (rr) and a homozygous white cow (rr)

The punnet square for the cross between the homozygous white bull (rr) and a homozygous white cow (rr) is as follows -

r r

r rr rr

r rr rr

Genotypic Ratio – All offspring’s are of genotpe rr

Phenotypic Ratio – All offsprings are of white color