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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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DNA on the Chopping Block
14 July 1999 6:00 pm
On this day in 1970, molecular biologist Hamilton Smith broke new ground for biotechnology. In two papers published in the Journal of Molecular Biology, he described a new class of enzymes--restriction enzymes--that scientists now use to precisely snip DNA. While studying the bacterium Haemophilus influenzae, Smith discovered that it slices up DNA from invading viruses. The blade, he found, is an enzyme that always cuts the viral DNA code where it finds a particular short sequence of nucleotides.
Smith and others later discovered many other restriction enzymes, all with their own preferred chopping sites. This specificity has made the enzymes a handy lab tool. They enable molecular biologists and geneticists to selectively chop DNA into pieces, which can then be assembled into new versions of the gene, inserted into the genomes of other organisms, or sequenced as part of an effort to map an organism's genetic material. For this work, Smith, along with Werner Able and Daniel Nathans, shared the 1978 Nobel Prize in physiology or medicine.
[Sources: Emily McMurray, Ed., Notable Twentieth Century Scientists (Gale Research Inc., ITP, 1995) and J. Mol. Biol. 51, 379-409 (1970).]