The humble fruit fly is perfect for unraveling biological mysteries because it shares so many genes and proteins with humans.
How could this be possible if not for evolution?
Kitchen Pest is Hero to Scientists http://www.chicagotribune.com/features/lifestyle/health/chi-fruit-flies-06-mar06,0,4669447.story
By Robert Mitchum | Tribune reporter
March 6, 2009
these very same genes that build fruit fly body parts build our body parts, mouse body parts, snake body parts, worm body parts, and the body parts of essentially all animals throughout the animal kingdom. That was really a shocking revelation to biologists, because the expectation was that very different animals with very different lifestyles and architectures would be built with different sets of genes. But the answer is no. Animals have very similar sets of genes, and this common tool kit exists throughout the animal kingdom.
Fruit fly research
At least a dozen fruit-fly laboratories operate on university campuses in the Chicago area, using the tiny insects to study such issues as sleep disorders, sexual orientation, evolution and gene therapy. The public may see the insect mainly as a kitchen pest, but to the 1,500 scientists attending the 50th annual Drosophila Research Conference, Drosophila melanogaster is one of the most important research animals in genetics, an encyclopedia of knowledge packed into a critter a tenth of an inch long.
By breeding fruit flies, early 20th Century scientists figured out the location of genes controlling certain traits, creating the first crude genetic map. In 2000, Drosophila was one of the first multicellular organisms to have its genome fully sequenced, providing a full blueprint of the organism.
Flies and humans share many genes and proteins, making the fruit fly ideal for unraveling biological mysteries
... an organism that seems so foreign and different from us really taught us a lot about our own selves and our genome."
Interesting but not essential to the evolution discussion
Politicians have been known to take potshots at fruit-fly research, most recently when Republican vice presidential candidate Sarah Palin cited it as an example of unnecessary earmarks at an October appearance. Though she was referring to a specific agricultural study taking place in Paris, Drosophila researchers were quick to defend their field, saying many fly projects were aimed at one of Palin's favorite concerns-autism.
In truth, similar arguments on behalf of Drosophila could be made for virtually any human disease or behavior. Since 1910, when T.H. Morgan discovered a white-eyed mutant fly among his stock of wild-type red-eyed flies, scientists have been manipulating the flies' genes to learn how they work-or fail.
In the Chicago area, at least a dozen fruit-fly laboratories operate on university campuses, studying such issues as sleep disorders, sexual orientation, evolution and gene therapy using the tiny insects.
Drosophila is so popular in part because researchers can breed and raise thousands of them very quickly and at a fraction of the cost of using rats or mice. A new generation of fruit flies can be created every 10 days, and females lay as many as 400 eggs during their lifetime.
In addition, exposing flies to radiation quickly creates random genetic mutations to study, and genetic tools can be used to flick genes on and off in fruit flies much more easily than in larger organisms.
"In spite of the hundreds of millions of years of evolution that have occurred between humans and Drosophila lineages, still 70 percent of the genes encoded in their genomes are similar," said University of Chicago geneticist Kevin White. "So we're able to use Drosophila ... to very rapidly do experiments and genetic manipulations that you just can't do in humans."
Last week, White and other researchers from the U. of C. and Argonne National Laboratory, near Lemont, published a paper in the journal Nature on a project that combined fruit-fly genetics with the latest in data-mining systems to find a new genetic marker of kidney cancer in humans.
Drawing upon nearly a century of work mapping Drosophila genes and the way their proteins interact, the team narrowed thousands of candidate genes down to a single protein, called SPOP, that is associated with faulty development of fly embryos. When the researchers tested human cancer cells for SPOP, they found it in 85 percent of renal cell carcinomas, a common form of kidney cancer.
The discovery could lead to tests that would identify kidney cancer at an early stage, improving treatment outcomes for patients, White said.
The lives of fruit flies may also hold insight into human behavior. Ravi Allada, a neurobiologist at Northwestern University, uses the insects to study circadian rhythms, the mechanisms that control sleep cycles in flies and humans.
"The big picture is that if we understand more about which genes are important for our circadian rhythms or our sleep and understand how those genes work, it will give us a better understanding of diseases that may be the consequence of such systems going awry," Allada said.
David Featherstone, a biologist at the University of Illinois at Chicago, stumbled on a peculiar fly model of human behavior when studying glutamate, an excitatory neurotransmitter in fly and human brains. Disrupting a gene in one part of the brain created male flies, nicknamed genderblind, that attempted to mate with both females and other males.
The finding may be relevant not only to research on sexual orientation but also to studies of muscle diseases and mental illnesses such as schizophrenia and depression where signals among nerve cells are disrupted, Featherstone said.
"We're not just trying to figure out stuff to entertain people or fill textbooks with irrelevant minutia about how the brain works," he said. "Ultimately we hope to understand the brain and gain the ability to engineer it."
Richard Carthew, a developmental biologist at Northwestern, is using Drosophila to study how RNA interference might be used to silence genes and nullify infectious viruses. Even after a century, the potential for fruit fly research t target="_blank">o benefit human health is still growing, he said.
"It's a very traditional, long-standing lab animal, but it shows no signs of tiring. It has good legs," Carthew said. "There's really nothing comparable to it."