Question

drosophila eye color is an x - linked trait. red eye color is dominant, and white eye color is recessive. which punnett square shows a cross in which the probability that offspring will be red - eyed males is 25 percent?

Explanation:

Step1: Analyze the first Punnett square

The first Punnett square has parents \(X^{R}X^{R}\) (female) and \(X^{r}Y\) (male). The offspring genotypes are \(X^{R}X^{r}\) (females) and \(X^{R}Y\) (males). The probability of red - eyed males (\(X^{R}Y\)) is \(50\%\) since there are 2 male offspring out of 4 total offspring (\(\frac{2}{4}=0.5 = 50\%\)).

Step2: Analyze the second Punnett square

The second Punnett square has parents \(X^{R}X^{r}\) (female) and \(X^{r}Y\) (male). The offspring genotypes are \(X^{R}X^{r}\), \(X^{r}X^{r}\) (females) and \(X^{R}Y\), \(X^{r}Y\) (males). The probability of red - eyed males (\(X^{R}Y\)) is \(25\%\) since there is 1 red - eyed male out of 4 total offspring (\(\frac{1}{4}=0.25 = 25\%\)).

Answer:

The second Punnett square (the one with parents \(X^{R}X^{r}\) and \(X^{r}Y\)) shows a cross in which the probability that offspring will be red - eyed males is 25 percent.