Question

in fruit flies, where red eye color (r) is dominant and x - linked while white (r) is recessive, what would be the result of a cross between a heterozygous red - eyed female (x^rx^r) and a white - eyed male (x^ry)? hint: draw a punnett square.
50% white - eyed male, 25% red - eyed male, 25% red - eyed female offspring
25% red - eyed female, 25% white - eyed female, 25% red - eyed male, 25% white - eyed male
0% chance of white - eyed flies and a 100% chance of all red - eyed females only.

Explanation:

Step1: Determine gametes

The female \(X^{R}X^{r}\) can produce two types of gametes: \(X^{R}\) and \(X^{r}\). The male \(X^{r}Y\) can produce two types of gametes: \(X^{r}\) and \(Y\).

Step2: Draw Punnett square

	\(X^{R}\)	\(X^{r}\)
\(Y\)	\(X^{R}Y\) (red - eyed male)	\(X^{r}Y\) (white - eyed male)

Step3: Calculate probabilities

There are 4 possible offspring. The probability of each offspring is \(\frac{1}{4}=25\%\).

Answer:

25% red - eyed female, 25% white - eyed female, 25% red - eyed male, 25% white - eyed male