Respuesta :
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:
[tex]50[/tex]% offsprings are white and remaining [tex]50[/tex]% 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)
[tex]2:21:1[/tex]
Thus, [tex]50[/tex]% offsprings are white and remaining [tex]50[/tex]% offsprings are Roan.