Question

1. show a cross between a pure red eyed female and a white eyed male.

what are the genotypes of the parents:
____ & ____

how many are:
white eyed, male ____
white eyed, female ____
red eyed, male ____
red eyed, female ____

1. show the cross of a red eyed female (heterozygous) and a red eyed male. what are the genotypes of the parents?

____ & ____

how many are:
white eyed, male____
white eyed, female ____
red eyed, male ____
red eyed, female ____

Explanation:

For Question 4:

Step1: Define parent genotypes

Eye color in Drosophila is X-linked; red ($X^W$) is dominant over white ($X^w$). Pure red-eyed female: $X^WX^W$; white-eyed male: $X^wY$

Step2: Set up Punnett square

	$X^W$	$X^W$
$Y$	$X^WY$	$X^WY$

Step3: Count offspring phenotypes

Count each phenotype from the Punnett square.

For Question 5:

Step1: Define parent genotypes

Heterozygous red-eyed female: $X^WX^w$; red-eyed male: $X^WY$

Step2: Set up Punnett square

	$X^W$	$X^w$
$Y$	$X^WY$	$X^wY$

Step3: Count offspring phenotypes

Count each phenotype from the Punnett square.

Answer:

Question 4:

Parent genotypes: $X^WX^W$ & $X^wY$
white eyed, male: 0
white eyed, female: 0
red eyed, male: 2
red eyed, female: 2

Question 5:

Parent genotypes: $X^WX^w$ & $X^WY$
white eyed, male: 1
white eyed, female: 0
red eyed, male: 1
red eyed, female: 2