Question

4 roan color is expressed by codominance in cows. cross a roan cow with a white cow. what chance do they have of having a white calf?

Explanation:

Step1: Determine the genotypes

Let \(R\) represent the allele for red color and \(W\) represent the allele for white color. A roan cow has the genotype \(RW\) (codominance: both alleles are expressed, resulting in roan color which is a mix of red and white hairs), and a white cow has the genotype \(WW\).

Step2: Set up the Punnett square

The cross is \(RW\times WW\). The possible gametes from the roan cow (\(RW\)) are \(R\) and \(W\), and the possible gametes from the white cow (\(WW\)) are \(W\) and \(W\).
The Punnett square is:

	\(W\)	\(W\)
\(W\)	\(WW\)	\(WW\)

Step3: Calculate the probability

Out of the 4 possible offspring genotypes (\(RW, RW, WW, WW\)), 2 have the genotype \(WW\) (white - colored calf). The probability \(P=\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}\). So \(P = \frac{2}{4}=\frac{1}{2}\) or \(50\%\)

Answer:

The chance of having a white calf is \(50\%\)