Genetics Proplem

Bar eye in Drosophila is X-linked and exhibits incomplete dominance.  Wild-type females have an average of 810 facets in the eye, while homozygous Bar females have an average of 59 facets.  Heterozygous females have a kidney-shaped eye with an average of 447 facets.  Males have either wild-type-shaped eyes with about 810 facets or Bar eyes with about 60 facets.


A) An autosomal recessive allele purple results in purple eyes when homozygous.  A female with Bar but homozygous for red eyes is mated with a male with normal-shaped but purple eyes.  What are the expected phenotypic ratios in the F1 generation?

a*F1 females and males will have kidney-shaped eye, red eyes.

b*F1 females will have bar eye, red eyes, and males will have kidney-shaped eye, red eyes.

c*F1 females and males will have bar eye, red eyes

d*F1 females will have kidney-shaped (447 facet) red eyes, and males will have Bar eye (60 facet) red eyes.


B) An autosomal recessive allele purple results in purple eyes when homozygous.  A female with Bar but homozygous for red eyes is mated with a male with normal-shaped but purple eyes giving a F1 generation. If one of the F1 males is mated with an F1 female, what are the expected phenotypes in the F2 generation for females?

a*1/16 red-eyed females with Bar eyes; 3/16 purple-eyed female Bar eyes; 1/16 red-eyed females with kidney-shaped eyes; and 3/16 purple-eyed female with kidney-shaped eyes

b*1/4 red-eyed females with Bar eyes; and 1/4 purple-eyed female with kidney-shaped eyes

c*3/16 red-eyed females with Bar eyes; 1/16 purple-eyed female Bar eyes; 3/16 red-eyed females with kidney-shaped eyes; and 1/16 purple-eyed female with kidney-shaped eyes

d*1/8 red-eyed females with Bar eyes; 1/8 purple-eyed female Bar eyes; 1/8 red-eyed females with kidney-shaped eyes; and 1/16 purple-eyed female with kidney-shaped eyes


C) An autosomal recessive allele purple results in purple eyes when homozygous.  A female with Bar but homozygous for red eyes is mated with a male with normal-shaped but purple eyes giving a F1 generation. If one of the F1 males is mated with an F1 female, what are the expected results in the F2 generation for males?

a*3/16 red-eyed males with Bar eyes; 1/16 purple-eyed male Bar eyes; 3/16 red-eyed males with kidney-shaped eyes; and 1/16 purple-eyed male with kidney-shaped eyes

b*3/16 red-eyed males with Bar eyes; 1/16 purple-eyed male with Bar eyes; 3/16 wild-eyed males with red eyes; and 1/16 purple-eyed males with wild-shaped eyes

c*1/16 red-eyed males with Bar eyes; 3/16 purple-eyed male Bar eyes; 1/16 red-eyed males with kidney-shaped eyes; and 3/16 purple-eyed male with kidney-shaped eyes

d*1/16 red-eyed males with Bar eyes; 3/16 purple-eyed male with Bar eyes; 1/16 wild-eyed males with red eyes; and 3/16 purple-eyed males with wild-shaped eyes