AP Biology 11
Mendelian Genetics – Concept 3 (Part 1: Sex linked)
Name:____________________
Date:____________ Bl:_____
Try This! A culture of white-eyed fruit flies ( Drosophila melanogaster ) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below.
Parental Generation Cross
White-eyes x red eyed
females males
F1 Generation (500 flies)
100% females red-eyed
100% of males white-eyed
F1 Generation Cross
F1 red-eyed x white-eyed
females males
50% females red-eyed
50% females white-eyed
50% males red-eyed
50% males white-eyed
1. The best explanation for the red-eyed F1 females is
(A) mutation (B) culture contamination (C) dominance (D) multiple loci (E) sex-linked dominance
2. There are white-eyed females in the F2 generation because
(A) white is a dominant allele (B) the white allele is autosomal (C) a mutation has occurred
(D) these F2 females have two white alleles (E) the white allele is located in the Y chromosome
3. Which of the following best describes the mode of inheritance of eye-colour in the white culture?
(A) autosomal (B) dominant (C) located on Y chromosome (D) sex-linked (E) lethal
AP Biology 11
Mendelian Genetics – Concept 3 (Part 1: Sex linked)
Name:____________________
Date:____________ Bl:_____
Try This! A culture of white-eyed fruit flies ( Drosophila melanogaster ) was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild-type) males. The F1 females were crossed with the white-eyed males from the original culture. The resulting phenotypes of the progeny are summarized below.
Parental Generation Cross
White-eyes x red eyed
females males
F1 Generation Cross
F1 Generation (500 flies)
100% females red-eyed
100% of males white-eyed
F1 red-eyed x white-eyed
females males
50% females red-eyed
50% females white-eyed
50% males red-eyed
50% males white-eyed
1. The best explanation for the red-eyed F1 females is
(A) mutation (B) culture contamination (C) dominance (D) multiple loci (E) sex-linked dominance
2. There are white-eyed females in the F2 generation because
(A) white is a dominant allele (B) the white allele is autosomal (C) a mutation has occurred
(D) these F2 females have two white alleles (E) the white allele is located in the Y chromosome
3. Which of the following best describes the mode of inheritance of eye-colour in the white culture?
(A) autosomal (B) dominant (C) located on Y chromosome (D) sex-linked (E) lethal