Question

You are a graduate student in the lab of a famous fly geneticist. You need to analyze a batch of mutant flies that were recently created in her laboratory to identify the single gene that is most likely mutated in each of the flies. Drag the mutations on the left to the appropriate blanks on the right to complete the sentences.
a. knirps (a gap gene)
b. hunchback (a gap gene)
c. hedgehog (a segment-polarity gene)
d. wingless (a segment-polarity gene)
e. kruppel (a gap gene)
f. even-skipped (a pair-rule gene)
1. Mutant fly F has predominantly lost abdominal structures, which is likely the result of a mutation in_____.
2. The wings are missing in mutant fly L, which is likely the result of a mutation in______.
3. Thoracic and abdominal structures are missing in mutant fly Q. The gene most likely responsible for this mutation is______.
4. Segment-sized sections of every other segment are missing in mutant fly Z. One likely candidate gene is_______.
5. Mutant fly X has lost the head and thorax. The gene most likely responsible for this mutation is_______.
6. The mutation observed in mutant fly O resulted in defects within the anterior or posterior regions of each segment. The gene that most likely caused this mutation is_______.

Answer 1

Answer:

knirps (a gap gene)

wingless (a segment-polarity gene)

kruppel (a gap gene)

even-skipped ( a pair-rule gene)

hunchback (a gap gene)

hedgehog (a segment-polarity gene)

Explanation:

The gap, segment-polarity and pair-rule genes play central roles in controlling embryonic development of arthropods. In the first place, the gap genes are associated with the formation of contiguous body segments, thereby mutations in these genes result in gaps in the normal body plan of the embryo. For example, in Drosophila melanogaster, mutations in the knirps, Krüppel and hunchback genes result in deletion of body segments. These genes are also known to regulate segment polarity genes, which determine the polarity of the embryonic parasegments by modulating Wnt and Hedgehog signaling pathways. Finally, the pair-rule genes work together with gap genes to control embryonic development of alternating body segments.