Answer:
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
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
