In the 19 December 1997 issue, the editors of Science offer their picks for the year's top ten scientific breakthroughs. Heading the list as "Science's 1997 Breakthrough of the Year" is the cloning of Dolly, the world's first cloned adult mammal. Science, which is published by the American Association for the Advancement of Science (AAAS) in Washington, DC, is one of the world's most often cited peer-reviewed journals. The annual top-ten list honors those advances that break new ground, unite scientific fields, and offer great potential benefits to society.
The cloning of Dolly sparked a firestorm of debate: do ethical concerns outweigh the possible social benefits of mammalian cloning? Can human cloning be far behind? Dolly also challenged scientists to revise their ideas about cell growth, development, and aging (Dolly's DNA is older than she is). Many pointed to the potential good that such techniques may offer, from making identical copies of prized livestock to cloning genetically modified animals that can generate human proteins useful in medicine and other areas. (A step in this direction has already been taken, according to a report in the same 19 December issue--building upon their Dolly experiment, Scottish researchers Schnieke et al. managed to produce cloned, transgenic sheep capable of pumping out a human blood coagulant used to treat hemophilia.) *
The nine runner-up breakthroughs are as follows:
- First runner-up--Mars Pathfinder/NASA's Discovery Program: The Mars Pathfinder mission marked the stunning debut of a series of planned space projects devised by NASA to more cheaply and more quickly gather data from the cosmos. Pathfinder and its little roaming robot Sojourner sent back a veritable flood of data which seem to suggest that the Red Planet may have been more Earth-like than previously thought. The next mission, Lunar Prospector, will launch on 5 January 1998 and will orbit and map the moon.
- Synchrotron light: 1997 was a banner year for a new generation of stadium-sized machines known as synchrotrons, which produce the brightest beams of light yet possible and which can illuminate the structural secrets of matter--down to the level of atoms. Among the year's achievements was an atomic-scale map of the nucleosome core particle, which manages to coil meters of DNA inside each cell.
- Clock genes: In 1997, researchers identified the first two mammalian clock genes--genes that act in virtually all organisms as built-in time-keepers to help maintain appropriate patterns of sleeping, eating and other basic functions. Researchers also discovered that individual cells in fruit flies keep their own time, independently of each other. With some evidence suggesting that humans and other mammals have similar clock genes, scientists wonder whether nature has preserved the circadian clock from the dawn of biological time.
- Single walled nanotubes: Essentially just sheets of graphite--carbon atoms arrayed in adjoining hexagons--that are rolled up and capped at the ends, nanotubes made of only a single wall of carbon are especially prized for their regular structures and predictable behavior. These tiny tubes may one day be perfect for everything from future electronic devices to ultra-strong materials. First discovered in 1991, in 1997 the tubes were tested, tweaked and filled with a variety of substances, bringing them that much closer to their potential.
- Microbial genomes: Steady progress by genome mappers yielded the complete genetic blueprints for a number of important microorganisms, including the laboratory workhorses E. coli and B. subtilis, as well as H. pylori, the bacterium responsible for ulcers. With these maps as their guides, scientists trying to learn more about hereditary diseases, fundamental life processes, and other DNA-related issues are no longer flying quite so blind.
- Gamma ray bursts: Gamma ray bursts are the most violent events known, exploding at the farthest edges of the measurable universe. Usually scientists must content themselves with remnants of these strange explosions, but in 1997 they caught a gamma ray burst in action--and, for the first time, with optical (visible light frequency) instrumentation. This mixture of good science and good luck promises to open a new window on an intriguing mystery.
- Neandertal DNA: Debate has long raged over whether the fossil evidence supports or denies a place for Neandertals as our direct ancestors. Then in 1997, scientists managed to extract and duplicate for analysis a tiny snippet of ancient mitochondrial DNA from the original Neandertal fossil. This new line of evidence suggests that Neandertals were merely our cousins, not our forebears, and rates as a welcome success in the often frustrating effort to make ancient DNA give up its secrets.
- Advances in understanding neurological diseases: The hope that neurological disorders might one day surrender to treatment got a little brighter in 1997. For example, there was the discovery of Nurr1, a receptor protein critical to the development of healthy dopamine circuits in the brain (Parkinson's disease is marked by a lack of dopamine); scientists found a new kind of brain lesion associated with Alzheimer's disease; and, though once thought impossible, severed spinal cord nerves in some experimental animals turned out to have the capacity for regrowth.
- Europa's ocean: As it swept by Jupiter, the Galileo probe picked up signals from one of the giant planet's moons--Europa--clearly suggesting that beneath its frozen sea flowed water. If true, that would make Europa the only other water-bearing body in our solar system, besides Earth. Given that Europa now seems to possess two of the most important preconditions for life--water and a source of internal heat--the implications are tantalizing.
The Breakthrough feature also looks at the leap science made into public consciousness during 1997 and how global warming changed from being merely a theory kicked around by scientists to one of the hottest public policy debates around. As in previous years, the editors of Science propose six areas of scientific research that promise the most exciting results in 1998: genetically altered agricultural crops; "pharmacogenetics"--technologies that can scan a person's genome for disease genes and custom-tailor therapeutic drugs; the complex relationship between biodiversity and the health of ecosystems; improved climate prediction strategies that might allow up to ten-year forecasts; the structure of the ribosome, the cell's protein factory; and supernovae data suggestive of an endlessly expanding universe. And finally, the editors score themselves on how well last year's predictions fared. The ten breakthroughs honored by Science were chosen by the editors, led by Editor-in-Chief Floyd E. Bloom, M.D. of Scripps Research Institute in La Jolla, CA. Bloom writes about the "Breakthrough of the Year" section in the 19 December editorial (available upon request).
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