Final answer:
In Drosophila, if the genes for purple eyes and curved wings are 21 map units apart, there's a 21% chance for recombination during meiosis. Since we divide the recombination percentage between two recombinant types, we expect 10.5% of 1000 offspring to have purple eyes and curved wings, totaling 105 flies.
Step-by-step explanation:
The question involves understanding genetic linkage and recombination in Drosophila melanogaster, a common research organism in genetics. If the genes for purple eyes and curved wings are 21 map units apart on chromosome II in Drosophila, this indicates the frequency with which recombinant offspring are expected to occur due to crossing over during meiosis. A map unit, or centimorgan, represents a 1% chance of recombination between two genes. Therefore, 21 map units suggest that there is a 21% chance for recombination to occur between the purple eye and curved wing genes. In a dihybrid cross involving linked genes, the expected ratio of offspring is modified from what would be anticipated with independent assortment. The 21% recombination frequency suggests that 21% of the offspring will be recombinants, while 79% will exhibit parental phenotypes. Since the question specifies that F1 wild-type females are mated with purple, curved males, we are interested in the recombinant phenotypes, which will be purple eyes and curved wings in this case.
The recombinant offspring will consist of both purple eyes and curved wings and the wild type for both traits. Since recombination is 21%, we have to split this percentage between the two types of recombinant progeny, which gives us 10.5% for each recombinant type. Thus, 10.5% of 1000 offspring would be expected to have purple eyes and curved wings: 0.105 (recombinant frequency) × 1000 (total offspring) = 105 offspring
Therefore, the expected number of flies with purple eyes and curved wings from the cross would be 105, which corresponds to option E.