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Name: Kunal
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Question:
Hi, I am a student in Astronaut High School in Titusville Florida. I am doing a science Research project on Genetic Inheritance in Fruit Flies. I am assigned to put a group of Fruit Flies in a chamber and then inject an attractive odor. I will then shock the flies as they come near. I will then collect the flies that are slow to move away from the shcoks and the flies that are quick. I will then breed the flies and see if the next generation of the quick flies are quick and if the new generation of slow flies are slow. However I am not sure how I am going to shcok the flies and also how I will analyze their genetic information to see if there is a trend. Could you please help me or give me any suggestions of how I may do this. Thanks for all the help,



Replies:
Your experiment sounds pretty difficult as well as subjective. I've done extensive fruit fly research and call tell you that you are going to have a really tough time trying to separate fast vs. slow fruit flies. Not only that, but you would have to keep the female fruit flies from the point of hatching separate from the males. If female fruit flies are near males, they will mate and store the sperm. Unless you separate your females just after they emerge from the eggs, you will have false data.

I would suggest trying a more classical approach and look at a physical phenotype like curly vs. straight wings, or red vs. white eyes. Ask your teacher to order your flies with 2 different phenotypes (one phenotype request all males and the other request all virgin females), keep them separate, and then set up your pairs. You will get more reliable data and it will be easier to calculate your results.

Saundra Sample


Why do you need to shock them? Why not simply collect those that stay farthest away from the odor and rebreed them? You will certainly put evolutionary pressure on the flies to evolve out of their preference for your odor. You are making the Lamarckian mistake, I think, because you feel some disaster must occur to the individual body during natural selection. Not so. All that is required is that the genes of a creature selected against not reproduce. Simply not allowing the flies that fly to the odor to reproduce is enough.

What you really need is some way to measure how attracted the flies are to the odor. Then you can measure this, as a function of generations since you started your selection, and see how it evolves. Perhaps measuring the density of flies as a distance from your odor source?

Grayce



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