Question

dilute
the dilute gene also influences color, making some pigeons a lighter shade of their inherited
feather color. the dilute gene is sex - linked, residing on the z chromosome and has two alleles:
‘dilute’ and ‘not dilute’.
calculate the probability of male offspring of the following cross being a lighter shade. use a
punnett square or math.

Explanation:

Step1: Define alleles & genotypes

Let $Z^d$ = 'dilute' allele, $Z^D$ = 'not dilute' allele.

• Male genotype: $Z^dZ^D$ (one Z has dilute, one has non-dilute)
• Female genotype: $Z^dW$ (Z has dilute, W has no dilute gene)

Step2: Set up Punnett square

Male gametes: $Z^d$, $Z^D$
Female gametes: $Z^d$, $W$

	$Z^d$	$Z^D$
$W$	$Z^dW$ (female)	$Z^DW$ (female)

Step3: Identify dilute male offspring

Male offspring genotypes: $Z^dZ^d$ (expresses dilute, light shade) and $Z^dZ^D$ (non-dilute, since non-dilute is dominant). 1 out of 2 male offspring has light shade.

Step4: Calculate probability

Probability = $\frac{\text{Number of dilute male offspring}}{\text{Total male offspring}} = \frac{1}{2}$

Answer:

The probability of male offspring being a lighter shade is $\frac{1}{2}$ (50%).