The Man Who Unlocked the Secret of DNA

You probably know that DNA (deoxyribonucleic acid) holds the genetic instructions for all living organisms.  You may not know that it took scientists almost a hundred years to figure this out.  We can thank Alfred Hershey, who was born on December 4, 1908.

DNA was first discovered in 1869 by the Swiss physician Friedrich Miescher.  Nevertheless, for the next century scientists believed that genetic information was carried by proteins, not DNA.  The structure of DNA appeared too simple to be genetic material.

Hershey, an American bacteriologist, studied bacteriophages, which are viruses that can infect bacteria.  (The difference between a virus and a bacterium is that a virus is not a living organism.  It does not have a mechanism for reproducing.  Instead, it infects and takes over other cells, using those cells’ own processes to create more viruses.  Pretty frightening, eh?)

Hershey and his partners observed that when two different bacteriophages infect the same bacteria, they often exchange genetic information with each other.  This led Hershey and his assistant Martha Chase to conduct the 1952 Hershey-Chase experiment, one of the most famous experiments in molecular biology.  They showed that when a bacteriophage infects a bacterium, its DNA enters the host cell but its proteins do not.

The Hershey-Chase experiment led to further studies that ultimately proved the hereditary properties of DNA.  Hershey shared the 1969 Nobel Prize in Physiology or Medicine for his discoveries.

Today, DNA is critical to life sciences, biology, genetics and forensics.  Agilent Technologies is known for producing some of the highest-quality synthetic DNA and RNA in the world with its microarrays.  Agilent equipment is also used for DNA analysis and the characterization of bacteriophages.


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