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Study Questions1. Suppose a recessive mutation has been found that impedes the proper development of ring canals so that the canals are never open for the flow of material through them. What do you think the phenotype might be? Would the observed phenotypes classify this as a maternal effect mutation or a zygotic mutation when homozygous?
2. Suppose it were possible to remove, by laser irradiation, the area of cortical cytoplasm in the syncytial blastoderm from which the cells forming the wing disc arise. What would be the effect of laser ablation if carried out in cycle 4 of cleavage?
3. It is possible to artificially increase the number of copies of bcd genes from one per haploid chromosome set to two or three. Can you predict what would be the result of increasing the number of bcd genes present in a female fly?
4. Can you speculate what the effect of loss-of-function mutations of tube and pelle might be?
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