In most kitchens the small flies that are found are Drosophila Melanogaster also called fruit fly. They are often brought in by ripened tomatoes, grapes and other perishable items from the garden. Drosophila melanogaster is a little two winged insect about 3mm long two winged insect that belongs to the Diptera, the order of the flies. The drosophila egg is about half a millimeter long. Fertilization takes about one day the embryo to develop and hatch into a worm-like larva. The larva eats and grows continuously, after two days as a third in star larva; it moults one more time to form an immobile pupa. Over the next four days, the body is completely remodeled to give the adult winged form, which then hatches from the pupal case and is fertile within about 12 hours. Fruit fly has four pairs of chromosomes: the X/Y sex chromosomes and the autosomes 2, 3, and 4. the fourth chromosome is very tiny and rarely heard from. The size of the genome is about 165 million bases and contains and estimated 14,000 genes (by comparison, the human genome has 3,400 million bases and may have about 22,500 genes; yeast has about 5800 genes in 13.5 million base bases). The genome has been completely sequenced and analysis of the data is now mostly complete. Fruit fly is a most commonly used model organism in studies such as genetics, biology, physiology and life history evolution. It is so useful because it is very small and easy to grow in the laboratory. It has a short generation time about two weeks and a high productivity. The mature larvae show giant chromosomes in the salivary glands. Drosophila has been used as a model organism for research for almost a century, and today. Part of the reason people work on it is because it is a small animal, with a short life cycle of just two weeks, and is cheap and easy to keep large numbers. Mutant flies, with defects in any of several thousand genes are available, and the entire genome has recently been sequenced. Fruit flies are normally somewhat difficult for students to handle. They often escape by flying away if not properly stored or if not carefully transferred and anesthetized during study. This may result in losses that can be detrimental to the results of the study.
The fruit fly experiment was conducted to understand chromosomal basis of inheritance. The source of genetic variation. To understand gene expression the different progeny that will be produce. The principle of sex linked gene for white eyes and aspterous wings. .
The inheritance of the White-eyed mutation is sex-linked and recessive. The predicted phenotype distribution for F2 dihybrid cross ratio is 9:3;3:1 Materials and methods
White eye male flies
Apterous female flies
Drosophila Media, formula 4-24
Clean media vials
Non-absorbent cotton tops
Lindane treated shelf paper
The sets and kits were provided by the university of Houston downtown lecturer.
First characteristics of our fruit flies were chosen: white eyes and aspterous wings. Then it was made sure that the vials were cleared and well labeled. 6 vials stock were created by setting up vials containing males and females of the same traits the flies had mated and stock was available to create the parental generation. But three vials of the flies had died, they were stuck to the media, and not sufficient flies were alive to reproduce number of pupa needed. New parental vials were created and allowed to mate. A total of 2 weeks was required for parental vials to start reproducing. Flies were transferred to different vial only leaving the pupa from the apterous vials, flies that had hatched from the pupa, the females were isolated and placed in a different media vial in an attempt to obtain virgin females After no larva formed in the vial containing female apterous flies only, it was determined they were virgins. Nine...
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