Nature's codes: a year of discovery

From in-vitro organs to extra-terrestrial life, from a better understanding of diseases to the development of genuine super-conductors, Steve Connor reviews the possibilities suggested by the scientific research breakthroughs of 1999, as chosen by the journal Science
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The Independent Online

The winner Stem cells: mothers of invention A series of astonishing developments in 1999 has raised the possibility of growing human organs in the laboratory, treating incurable diseases with tissue transplants and even cheating the inevitable physical and mental deterioration of old age. At the heart of the research is the discovery and isolation of human stem cells, immature cells that can develop into any of the dozens of specialised tissues of the body.

The winner Stem cells: mothers of invention A series of astonishing developments in 1999 has raised the possibility of growing human organs in the laboratory, treating incurable diseases with tissue transplants and even cheating the inevitable physical and mental deterioration of old age. At the heart of the research is the discovery and isolation of human stem cells, immature cells that can develop into any of the dozens of specialised tissues of the body.

Although stem cells were discovered at the end of 1998, it was this year that researchers capitalised on the findings and produced over a dozen landmark scientific papers on the remarkable abilities of these cells. Science says the work has demonstrated the extraordinary potential of stem cells to heal many of the most intractable illnesses of the late-20th century, ranging from Alzheimer's disease to cancer.

"We salute this work, which raises hopes of dazzling medical applications and also forces scientists to reconsider fundamental ideas about how cells grow up, as 1999's breakthrough of the year," the journal says. "Stem cells may one day be used to treat human diseases in all sorts of ways, from repairing damaged nerves to growing new hearts and livers in the laboratory."

Stem cells from embryos can develop into any specialised tissue, but scientists have also found that adults possess stem cells in their vital organs that can equally learn a different trade: brain cells can become blood cells; bone marrow cells can become liver tissue. Studies have shown that the genetic instructions dictating the specialisation of a cell can be rewritten, a discovery that upsets decades of accepted wisdom.

"Stem cells taken from the brains of mice could take up residence in the bloodstream and bone marrow and become mature blood cells," Science says. Such work could become the foundation of medical treatments to repair damaged organs by transplanting healthy tissue grown from stem cells. "If it lives up to its early promise, it may one day restore vigour to aged and diseased muscles, hearts and brains - perhaps even allowing humans to combine the wisdom of old age with the potential of youth."

Runners-up

Genomics: the decoding of the genes A plethora of research papers revealed how quickly scientists are progressing in decoding the genes not just of human chromosomes but of other organisms. The work promises to unleash vast amounts of genetic information about the DNA of all life on Earth, leading among other things to a greater insight into human illnesses and diseases. This year scientists published the genetic sequence of a human chromosome, number 22 of the 23 pairs. Another advance this year was the decoding of an entire genome - the complete complement of chromosomes - of a multi-cellular organism, the nematode worm Caenorhabditis elegans. We also saw the publication of the entire code of important disease-causing microbes, such as Chlamydia pneumoniae, which causes respiratory infection, and Campylobacter jejuni, a food-poisoning bacteria. In the words of Science: "The floodgates broke open on genomic research in 1999, releasing a torrent of data."

Quantum molecules: strange matter Scientists created a bizarre kind of gas this year that may one day help them to probe the basic nature of matter and build the next generation of atomic clocks and lasers. By inducing atomic collisions between potassium atoms in a certain quantum state, the scientists created a cool vapour in which the atoms of the gas were arranged in a precise sequence or ladder of energies. The research may lead to a new breed of resistance-free electricity super-conductors. "This achievement clears the way for the creation of a completely new type of quantum matter," Science says.

Ribosome structure: anatomy of a protein factory The curtain finally came up on one of the stars of cellular biology - sub-microscopic structures called ribosomes, which manufacture the body's proteins. After 10 years of trying to work out the architecture of the ribosome, scientists published the blueprint this year for one of the most complex molecular mechanisms of life. The ribosomes of a cell somehow translate the code of DNA into the sequence of amino acids that make up the thousands of proteins needed for organisms to survive. "Structural biologists had struggled for decades to probe this complex molecular machine but were thwarted until recently," Science says. Using X-rays to penetrate the ribosome's complex, three-dimensional structure, scientists have come up with a clear picture of how this protein factory is built.

Planets galore: can there be life in outer space? A string of new planets was found beyond our own solar system, given away by the gravitational wobble the planets caused on nearby stars. Nearly 30 planets have been detected in this way, including one seen in silhouette, floating past its own sun. This week scientists announced that they had detected the first reflected light from a distant planet, which raises the prospect of analysing the chemical composition of the planet to search for signs of life. "The latest batch of exoplanets even contains worlds that orbit in the habitable zone of their parent stars, where liquid water and life could exist. While none of the planets discovered so far actually has what it takes to support life, theorists think that the universe should be teeming with more planets that await discovery," Science says.

Life: a billion years older than we thought The origins of complex life - cells with distinct nuclei - were pushed back a billion years. Studies of Australian rocks suggested that they contained eukaryotic cells that lived 2.7 billion years ago. Scientists extracted chemical residues from Australian shale and found organic chemicals made only by eukaryotic cells. The discovery rewrites the early history of life on Earth.

Memory making: a matter of chemistry New methods have allowed scientists to film nerve cells laying the foundations for new memories. The power of the technique shone through when researchers used it to engineer a strain of laboratory mouse with an improved memory. It could find its way out of a familiar maze more quickly than normal.

Flat universe: more like a pancake than a balloon Cosmologists may have rid themselves of flat-Earthers but they have concluded that the Universe is a flat, stretched-out piece of space. A flat universe requires just the right amount of density of matter, and information from a variety of locations this year showed ripples in the microwave background radiation, the afterglow of the Big Bang, that exactly fit the flat-Universe theory.

Light trap: harnessing the power of photons Several teams of researchers have developed photonic crystals that trap and direct specific wavelengths of light. They hope to harness the energy in the same way that transistors on computer chips harness electrons. Optical computers that use light instead of electricity could be the next step.

Cosmic flashbulbs: a 30-year mystery solved? For three decades astronomers have been mystified by cosmic ray bursts, intense flashes of invisible energy that emit more power in a few seconds than the sun does in 10 billion years. This year, scientists were able to link them - at least partially - to the collapse of massive stars or supernovae. Since 1997 an armada of telescopes has been trained on the sky to monitor such flashes of gamma radiation. "Researchers now seem to be closing in on the true nature of the massive blasts. At least some are apparently the birth cries of black holes, formed when rapidly rotating super-massive stars collapse upon themselves," Science says. Satellites to be launched over the coming years should solve the mystery once and for all.

Further information: 'Science', vol 286, p2238.

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