Fruit flies, like all insects, are covered with fine, hair-likebristles, which serve as sensory structures.
You discover a male fruit fly, which has short, under-developedbristles. Â
You cross this male fly with a female fly with normal bristles.Of 400 progeny, you count 205 flies with normal bristles and 195with short bristles. You cross two F1 flies (both haveshort bristles) and count 400 progeny; 267 have short bristles and133 have normal bristles.
A test cross of the F1 short bristle flies results inthe following results: 195 flies with short bristles and 205 flieswith normal bristles.
A reciprocal cross (short-bristled female flies with normalmales) yields similar results in the F2.
A. Do what of inheritance pattern do you think this trait isshowing ? Â Â
B. What conclusions can you make about the allele causing shortbristles and the genotype of the original male?
C. What is the best explanation for this phenotypic pattern?
I chose
A. Homozygous dominant lethality
B. dominant
C. Individuals with the genotype BB and Bb show SHORT bristles,and those with bb show NORMAL bristles
But I got 4/6 points, not sure which I got wrong.
