Model Organisms
Phage Plants Nematode Fly Rodents Humans

The bacterial virus known as the "phage" is perhaps the world’s most simple biological entity capable of directing its own duplication. The phage is little more than a strand of DNA contained within a protein coat. This simplicity was attractive to early researchers trying to determine whether the molecules of inheritance were proteins or DNA. In a famous "blender" experiment at Cold Spring Harbor Laboratory, Alfred Hershey and Margaret Chase allowed phages tagged with radioactive ions to infect a cell, and confirmed that DNA was indeed the hereditary molecule. For more details, see a diagram of the famous blender experiment on the Access Excellence Web site.

micrograph of bacteriophagesOn the phage bacterial virus as one of the original model organisms for genetics:
"The phage was discovered around 1915 and [it was thought] that maybe because they multiply and kill bacteria they would be effective antibiotics. So they were studied largely initially to cure disease, but that didn’t seem to work out, and twenty years later a few scientists said, ‘Well maybe since they contain DNA they would be good model systems for studying the gene.'

"The idea was that you could do experiments overnight; if you were breeding corn, you could only have one cross per year. If you went down to Florida, maybe you’d have two crosses per year. With phages you can get a cross every day."

James Watson, Co-discoverer of the DNA double helix and president of Cold Spring Harbor Laboratory

On viruses and the way genes are organized:
"They don’t have very much DNA at all, they sometimes will code three different proteins with the same DNA by just shifting how they’re doing it. There’s nothing simple and elegant and neat about the way genes are laid out. Life uses every trick in the book to get a little bit of an advantage. Not tidy, but very effective."

Eric Lander, Director, Whitehead Institute's Center for Genome Research



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