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Seven Things in Common with a Fruit Fly |
Sleep
Tiny fruit flies sleep for 6-12 hours every night, are difficult to rouse and caffeine keeps them awake. Sound familiar? Researchers are finding that fly sleep behavior is remarkably similar to humans and so are the underlying molecules that control sleep behavior.
Scientists have found that sleep is controlled by a set of genes in Drosophila (or fruit fly) that are very similar to certain human genes. Humans have genetic disorders in sleep like insomnia, where individuals have trouble falling and staying asleep. This and this behavior may be controlled by genes like the Clock gene. Clock was originally discovered in fruit flies in a mutant that didn’t respond to a normal 24 hour daily rhythm. Many other genes have been found in flies that have implications to studying sleep in all organisms.
To date scientists don’t know exactly why we sleep or why some people need less sleep than others. Scientists do know that sleep is essential and lifelong sleep deprivation may reduce lifespan. Research in a simple but related system like the fruit fly can begin to address questions such as why sleep is important and how it affects overall health.
Memory
Many animals learn that one stimulus can be paired with a response, which is a type of learning called conditioning. A handful of Some fruit fly researchers asked the same question and found that just like Pavlov's dog who associated a bell ringing with food, flies can associate smells with electric shock. This odor avoidance behavior tells us that flies have a memory.
Further research has told scientists that learning and memory are influenced by has genetic factors that control it. Fruit fly mutants like dunce and amnesiac have lost the ability to either learn or remember in the odor avoidance test. When these flies are exposed to an odor at one end of a tube they continue to be attracted to it despite getting a shock on the foot.
Researchers are finding that humans and flies share brain circuitry associated with memory. This makes flies a very good model for studying the parts of the brain required for learning and memory. If we can understand learning and memory in the fly brain, it will help researchers can apply this knowledge to disorders that affect human memory such as Alzheimer's disease or learning disorders.
Body Plan
Head and shoulders, knees and toes, knees and toes….. Lots of creatures can sing this song - from humans to elephants and even flies. The order of the body parts is always the same and that is because the genes controlling the pattern of the body are the same in almost all organisms.
Regions of DNA called the Hox genes are responsible for telling the growing embryo where the head, limbs and body should develop and making sure this happens in the correct ey are placed in order. It would be horrible if a leg or other body part developed in the wrong place – but it The worst thing that could happen is a leg or other body part is put in the wrong order, except that has already happened in flies. A type of mutation in flies called Antennapedia has legs where the antennae are supposed to be because of a mistake in patterning the body. Clearly there are no humans with legs growing out of their heads, but the research done in flies tells us that the Hox genes are turned on in a particular pattern to tell the body how to develop.
Similar patterns of Hox gene expression between flies and mice means that studying the fly version of the Hox genes can give clues to how the mammalian body is organized during development.
Addictions
Addiction to drugs and alcohol affects millions of people, motivating scientists to learn why and how certain drugs are addictive. Drosophila makes a good model system for studying addiction because humans and flies react the same to variousdifferent drugs.
Some scientists are studying cocaine and alcohol addictions in fruit flies. When flies are fed alcohol, they get tired, fall over and have difficulty learning. Frequent exposure to alcohol causes flies to develop one of the hallmarks of human addiction where we become tolerant to increasing doses. When flies are given drugs like cocaine, they respond in a similar way to us with jerky movements, tremor and even death.
Humans and flies display the same types of behaviors when given cocaine or alcohol because we share the same types of molecules that process that drug. This fact makes flies a simple system for studying how drugs are processed in the body which is key to understanding why a drug is addictive. Flies also offer the opportunity to study the biology of addiction without the contributions of social and environmental pressures.
Junk Genes
The human genome is made up of 3 billion bases pairs of DNA; there is enough DNA in your body to stretch to the sun and back 50 times. In that large genome there are 20,000-25,000 genes, but there are not enough genes to fill all of the billions of units of DNA. Creatures like flies, worms and humans all have tons of unused, or ‘junk’, DNA which begs the question – what is junk DNA good for?
New research in flies is telling us a lot about what junk DNA can do. It may allow genomes to create new genes. A completely new gene has been discovered only in flies and is not similar to any gene found before. It may have been assembled in junk DNA. In these stretches of non-coding DNA you can find sequences of ‘jumping genes’ called transposable elements that are probably leftovers from harmless viruses. Transposable elements may provide a way to generate a new gene by jumping around the genome and picking up pieces of working genes along the way.
The finding of new genes in flies has made the potential of junk DNA much more clear to scientists. All of that unused DNA may be a playground for new genes to arise that may help the organism survive.
Erratic Behaviour
Scientists study fruit flies because of their behaviors are straightforward, predictable and controlled by specific genes. Flies are organisms that are considered to be input/output systems that only act when given a stimulus and are not affected by inputs that affect human decisions like emotions and past experiences.
It appears that fly behavior is much more sophisticated than we ever thought. New research has found that flies do not always respond the same way to the samea stimulus, suggestingmeaning that there the fly brain is much more than just an input/output circuit. Interestingly, flies can also act spontaneously by generating new behaviors without a stimulus. This could mean that fruit flies have something that resembles the human property of free will.
Do flies have free will? Maybe not in the classical sense but they have evolved a way to produce entirely new behaviors. Perhaps we haven’t looked closely enough at flies to find out how similar we really are to us flies really are.
Bananas
Fruit flies love bananas, they eat the peel and the flesh and they love the soft interior to lay their eggs. For science fun at home - you can breed fruit flies using bananas, just place a banana in a humid container and add one or two fruit flies. Watch the flies grow!
But, if you would rather leave the fly science to the lab, then getting rid of fruit flies in your home takes only an empty pop bottle with a bit of sugar water in the bottom and a small funnel taped into the top. Flies will follow their smell and enter the container but then won’t be able to find their way back out.
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