Imagine that you observe the following mutants in Drosophila. Based on the pheno

Question

Imagine that you observe the following mutants in Drosophila. Based on the phenotype and inheritance described, assign each mutant into one of the following categories: maternal effect gene, gap gene, pair-rule gene, segment polarity gene, or homeotic gene. (10 points each, 50 total) a. In homozygotes, larval embryos fail to develop. At death, wing, leg, heart, and gut primordia are present in duplicates with mirror-image orientations. b. Homozygous females are normal but produce larvae that have a head at each end and no caudal structures. Homozygous males are normal and have normal offspring. c. Homozygotes have shortened abdomens, missing segments Al through A4 d. Affected flies have halteres growing where their eyes should be e. Homozygous embryos lack parasegments 2, 4, 6, 8, 10, 12, and 14

Explanation / Answer

a) this is the case of Homeotic gene because this gene if not expresses normally, then may develop later in the development because of mutation.

b) is causing by Maternal effect gene. Here Nanos is present but Caudal is absent.

Part c is causing by absence of gap genes because these divides the body into segments.

d) this is the case of Segment polarity gene because these genes decide the boundaries of a segment.

e) this is the case of pair rule genes because these genes if absent, they make disappearance of alternative partitions of segments.

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