Directional preference in Drosophila melanogaster*

Drosophila melanogaster is an organism that is commonly analyzed and used to understand basic behavioral and genetic mechanisms. We are examining whether there is a basis for directional preferences in flies and whether this has genetic underpinnings via a directional choice maze set to north versus south, where each fly makes 10 choices of whether to go north or south. Of flies that exit the maze, we select the top 20% and bottom 20% to give rise to the next generation.  Successive generations are run through the maze for 15 generations. Analysis of the data will show whether flies have a selective preference over successive generations, indicating a genetic basis for directional preference. We are using positive phototaxis experiments in our Y-maze as a control. These findings could lead to a better understanding of the potential genetics of magnetic orientation and directional preference in flies, which has been documented in other organisms.

*Research in conjunction with Dr. Mike Baltzley

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Drosophila melanogaster

You may have had this experience: sitting down while eating, minding your own business, you realize that you are under attack from small, very determined, very persistent flies. The fruit fly, Drosophila melanogaster, also known as the vinegar fly, is a beloved organism for genetic and molecular studies (although highly annoying if you have encounted the situation described above).

The name Drosophila melanogaster means "black-bellied lover of dew" in Greek. Drosophila have been used in countless scientific studies, beginning in the early 1900s when Thomas Hunt Morgan claimed the fly as his research organism. Although Morgan originally worked to disprove genetic hypotheses developed by Gregor Mendel, Morgan is now honored as the father of classical Drosophila genetics (in the end, Morgan's research supported Mendelian genetic principles beautifully).

Drosophila continue to be widely used as a research organism for the following reasons: (1) they are cheap, (2) they have a short life-cycle of approximately 10 days from egg to fertile adult, (3) they are amazingly fecund; one female can lay around 500 eggs (4) people aren't generally bothered if you bump off hundreds of flies at a time, (5) their genetics are well-documented, they have only four chromosomes, and databases of genetic information are easliy available, (6) they are more like us than you might think! As it turns out, roughly 60% of human disease genes have counterparts in Drosophila.

And because I am always asked...

How to get rid of fruit flies:

It's true, fruit flies are very pesky, especially if you are not enjoying them for their research qualities. The reason flies hang around is because you have something they want - old fruit laying out, recycling with beer/soda residue, drips between the garbage can and the liner - the trick is to find and remove whatever is attracting the flies. That is the sure-fire method.

If that fails, below are instructions for trapping and removing fruit flies.

1. Take an empty 2-liter bottle and cut around the plastic to remove the top section, about three inches below the neck.

2. Place something delicious to flies in the bottom of the bottle (options include apple cider vinegar, a bit of leftover beer, mushed up fruit).

3. Invert the top part of the bottle that you removed and place it inside the bottom portion of the bottle such that it creates a funnel to the delicious morsel/fly attractant.

4. Seal the top and bottom portions of the bottle together - I recommend duct tape, but whatever works.

5. Flies will be attracted into the bottle via the funnel opening, but will have a hard time figuring out how to escape. When you feel that your capture is complete, seal the bottle opening and dispose of the bottle. You can always make another one.