Question

1. Explain the advantageous of studying Drosophila genetics ). What are the reasons for studying Drosophila in our labs ? Explain and give an example for: a marker, a balancer in terms of Drosophila genetics.  

Answer 1

Drosophila flies have both X and Y chromosomes and autosomes

75 % of  genes that cause disease in humans are also found in Drosophila.

There are many reasons the Drosophila is a popular choice as a model organism

1. Its culture require little equipment space, and expense even when using large cultures
2. It can be safely and readily anesthetized (usually with ether, carbon dioxide gas, by cooling)
3. Its morphology is easy to identify once anesthetized Drosophila
4. Drosophila has a short generation time about 10 days at room temperature so several generations can be studied within a limited period
5. females lay up to 100 eggs per day, and perhaps 2000 in a lifetime
6. Males and females are readily distinguished, and virgin females are easily isolated and facilitating genetic crossing
7. It has only four pairs of chromosomes 3 autosomes and 1 pair of sex chromosomes
8. Males do not show meiotic recombination facilitating genetic studies
9. "balancer chromosomes" carrying visible genetic markers can be used to keep stocks of lethal alleles in a heterozygous state without recombination due to multiple inversions in the balancer
10. The development of this organism from fertilized egg to mature adult is well understood
11. Its complete genome was sequenced and first published in 2000
12. Sexual mosaics can be readily produced providing an additional tool for studying the development and behavior of these flies

Genetic markers are commonly used in Drosophila research

example within balancer chromosomes. most phenotypes are easily identifiable either with the naked eye or under a microscope

list of a few common markers

1. Cy¹: Curly; the wings curve away from the body, flight may be somewhat impaired
2. e¹: Ebony; black body and wings (heterozygotes are also visibly darker than wild type)
3. Sb¹: Stubble; bristles are shorter and thicker than wild type
4. w¹: White; eyes lack pigmentation and appear white
5. bw: Brown; eye color determined by various pigments combined
6. y¹: Yellow; body pigmentation and wings appear yellow, the fly analog of albinism

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