Describe the life cycle of drosophila and how long each stages takes. Why should

Question

Describe the life cycle of drosophila and how long each stages takes. Why should virgin female flies be used and how do we harvest virgin female flies? Please name both the phenotypes and genotypes of the flies shown here. Phenotype: ________ ________ ________ ________ ________ Genotype: ________ ________ ________ ________ ________ Sex: ________ ________ ________ Describe the life cycle of drosophila and how long each stages takes. Why should virgin female flies be used and how do we harvest virgin female flies? Please name both the phenotypes and genotypes of the flies shown here. Please describe the polytene chromosome and explain how it is formed A newly discovered drosophila has abnormal pattern of sternite due to a recessive mutation in a gene designated as T. Please design an experiment to find out if the gene T is autosomal or X-linked.

Explanation / Answer

1.A female lays around 400 eggs. The eggs hatch into first instar larvae within 24 hours. different regions of larvae become well defined several hours before the transition. anterior region of the head houses a special structure called acron while its posterior end contains the telson. Three thoracic segments and eight abdominal segments appear between the head and the telson.

The first instar larvae feeds on substrates for around 25 hours and shapes into a larger worm like form called the second instar larvae. The second instar larvae take the next 24hours to molt into the third instar larvae.

Pupa develops to progressively become darker and metamorphoses into the imago. As the third in larva becomes pupa metamorphoses occurs to convert it to an adult fly. During the pupal stag Drosophila acquires wings and legs through hormone induced metamorphoses. These structuresare already present in the larva as imaginal discs. The imaginal discs are small sheets of epidermal cells derived from the cellular blastoderm and accommodate around 40 cells each during the time of formation.

2.Polytene chromosomes are commonly found in the salivary glands of DrosophilaSpecialized cells undergo repeated rounds of DNA replication without cell division (endomitosis), to increase cell volume, forming a giant polytene chromosome. Polytene chromosomes form when multiple rounds of replication produce many sister chromatids that remain fused together.

3. 2nd one phenotype have small wing due to X-linked Dp110KD   hemizygous male

1st one propably wild type male 4th one wild type female.

2.Laboratory studies have revealed a significant “cost of mating” to Drosophila melanogaster females in the form of reduced longevity. The effect is attributable to nonsperm components of the ejaculate.

5. If it is X linked recessive female with the phenotype will have all male offspring with the phenotype

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