Duck, Duck, Golden Goose!

Geese, the most aggressive of all poultry. Image courtesy of Wikipedia.
Geese, the most aggressive of all poultry. Image courtesy of Wikipedia.

The second annual Golden Goose Award ceremony was held on September 19th. The Golden Goose Award is given to obscure federally funded research projects that ultimately resulted in breakthroughs with wide-ranging benefits. The name comes from The Goose That Laid the Golden Eggs fairytale. One of the 2013 awardees exemplifies the potential application of very basic and somewhat obscure science.

In 1966, Thomas Brock, a microbiologist, and his undergraduate research assistant, Hudson Freeze, set out for Yellowstone. They were interested in organisms that live in the most extreme of conditions. They collected bacteria thriving in the hot springs of the park. Among the samples they collected, one was called Thermus aquaticus. Molecular biologists around the world know it by its more common nickname, Taq.

This rare organism just happened to make one of the most important enzymes in modern molecular biology. In the early days of molecular biology, scientists were eager to study DNA, but had trouble collecting usable quantities of DNA. The amount of DNA in a cell is quite small and you can lose a significant portion while isolating it. Making more copies of the DNA, would solve this problem. Scientists already knew that cells made new copies of their DNA by separating the two strands and using an enzyme called DNA polymerase to make a new copy from each strand. But how could you force a cell to undergo that process many, many times?

You can force the strands of DNA to separate by heating them up, but that heat destroys the enzyme’s ability to create new strands of DNA. Enter the Golden Goose. The DNA polymerase enzyme from the Thermus aquaticus (Taq) is stable at very high temperatures. Because it lives in the boiling water of a hot spring, it’s DNA polymerase no choice but to be functional at high temperatures. If Taq’s enzyme (and a few other key ingredients) is added to DNA, many copies of DNA can be generated by going through a cycle of heating the strands, making new copies, and cooling. This process is known as the polymerase chain reaction or PCR.

This discovery revolutionized molecular biology and the study of DNA. DNA could now be generated in quantities large enough to study. This allowed molecular cloning of genes. It also allowed the development of genetic tests, examination of crime scene evidence, and contributed to the sequencing of the human genome. Not bad for a field trip to Yellowstone to gather samples out of a hot spring.

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