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Another cross in Drosophila involved the recessive, X-linked genes yellow (y), white (w), and cut (ct). A yellow-bodied, white-eyed female with normal wings was crossed to a male whose eyes and body were normal but whose wings were cut. The F1 females were wild type for all three traits, while the F1 males expressed the yellow-body and white-eye traits. The cross was carried to an F2 progeny, and only male offspring were tallied. On the basis of the data shown here, a genetic map was constructed.
- (a) Diagram the genotypes of the F1 parents.
- (b) Construct a map, assuming that white is at locus 1.5 on the X chromosome.
- (c) Were any double-crossover offspring expected?
- (d) Could the F2 female offspring be used to construct the map? Why or why not?
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- The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly that is homozygous for normal wings and has a hairy body and a fly with vestigial wings that is homozygous for normal body. The wild-type F1 flies were crossed among each other to produce 1024 F2 offspring. Which phenotypes would you expect among the F2 offspring, and how many of each phenotype would you expect? Group of answer choices 192 wild type, 256 vestigial, 64 hairy, and 192 vestigial and hairy All vestigial and hairy. 576 wild type, 192 vestigial, 192 hairy, and 64 vestigial and hairy All wild type 256 wild type; 256 vestigial, 256 hairy, and 256 vestigial and hairyarrow_forwardIn Drosophila, sepia eyes (se), curled wings (cu) and ebony body (e) are found, in this order, on chromosome 3. Sepia is 22 map units from curled, which is 12 map units from ebony. A true-breeding female with sepia eyes and ebony body is crossed to a true- breeding male who has curled wings. The resulting F1 progeny from this cross are all wild type. An F1 female is test crossed to a male expressing all three traits. Assuming a Coefficient of coincidence of 1: What proportion of the F2 progeny will express only the sepia trait? If there are 1000 total flies, what number will express curved only?arrow_forwardIn Drosophila melanogaster, red eyes are dominant over white and the variation for this characteristic is on the X chromosome. Vestigial wings (v) are recessive to normal (V) for an autosomal gene. Predict the appearance of offspring of the following crosses: XW/Xw V/v×Xw/Y v/v, Xw/Xw V/v × XW/Y V/v.arrow_forward
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