Please answer both questions: In the parental generation, a male fruit fly with
ID: 273002 • Letter: P
Question
Please answer both questions:
In the parental generation, a male fruit fly with a gray body (BB) and straight wings (CC) was crossed with a female fruit fly with a black body (bb) and curved wings (cc). The F1 flies all had gray bodies and straight wings. A female F1 fly was crossed with a male fly that was homozygous recessive for both traits. The female fly had the B and C alleles on one chromosome and the b and c alleles on the other chromosome. Because the genes are linked, the expected ratio in the F2 generation would be 50% with gray bodies and straight wings and 50% with black bodies and curved wings. But four different phenotype combinations appear in the offspring, with two expected, but there were also offspring with gray bodies and curved wings and offspring with black bodies and straight wings. Which of the following best explains what happened? Skipped Multiple Choice A recombination occurred during the formation of the F1 female's egg cells. A mutation changed the genotype of a portion of the flies in the F2 generation. A mutation changed the genotype of the F1 male's DNA. A recombination occurred during the formation of the F1 male's sperm cells. Independent assortment resulted in the new combination of traits in the F2 generation.Explanation / Answer
Answer:
1) a recombination occured during the formation of F1 female's egg cell.
explanation: As the female is heterozygous (BC/bc) and in Drosophila only females have the ability to produce recombinant germ cell. Drosophila male does not show recombination. A proper independent assortment would have produced all four phenotype in 1:1:1:1 ratio (25% of each). Thus, for given condition it will be more logical to conclude a small amount of recombination has been taken place or the linkage is not absolute.
2) More information required about the options .