Question

Predict the phenotypic ratios of offsprings when a homozygous white cow is crossed with roan bull

Answer 1

The phenotypic ratio obtained from a cross for only genetic trait, assuming it follows the simple mode of inheritance which is complete dominance, it would be 100% white cow, assuming roan bull is recessive.

Answer 2

Answer:

$50$% offsprings are white and remaining $50$% offsprings are Roan.

Explanation:

Let "Roan" be a co dominance trait.

The allele for white color is represented by "A"

And the allele for trait mixing with allele of white color to produce Roan color be "R"

Now the genotype of Cow will be "AA"

and the genotype of roan bull will be "RA"

Now a cross is to be carried out between homozygous white cow(AA) and  roan bull (RA)

The following offsprings will be produced from the above cross

AA * RA

RA,AA, RA, AA

Thus, out of four offspring two will be homozygous white while two will be Roan colored.

Thus, the phenotypic ratio is

White(AA) : Roan(RA)

$2:21:1$

Thus, $50$% offsprings are white and remaining $50$% offsprings are Roan.