Keeping crops healthy
Crop diseases cost the world an estimated $220 billion every year and put millions at risk of starvation. But with a little help from scientists, crops -- and we who depend on them -- may soon gain the upper hand.
In two papers published July 28 in Science, an international consortium of researchers report that even dramatically different diseases attack a small set of targets in plants.
By identifying the ways plants might be most vulnerable to attack, the discovery enables crop researchers to focus on protecting these few targets, potentially speeding up the task of developing disease-resistant crops.
The team sorted through more than 8,000 proteins in a small plant related to cabbage to examine the different ways the proteins interact with each other. The result, a tangled map of the plant's chemical defense mechanisms, is akin to the street map of a city.
The researchers discovered that a plant's message traffic tends to pass through major intersections, making them a perfect target for diseases. By causing a wreck at a major message intersection, a disease can devastate the plant's ability to fight back. But the plant can also conserve resources and watch just a few hubs to look out for many different diseases. Now, instead of sifting through tens of thousands of possible ways to protect a plant, crop disease researchers can focus on a few hundred.
-- Raleigh News & Observer
Neanderthals crowded out
The Neanderthal never stood a chance. Modern humans who entered Europe may have outnumbered their hominid relatives 10 to 1, a new study has found. The research, published online July 28 in Science, helps explain why Neanderthals -- who had lived in Europe for at least 200,000 years -- died out about 40,000 years ago, soon after modern humans migrated from Africa.
Researchers had long surmised that human population growth may have overrun the Neanderthals, said study lead author Paul Mellars, an archaeologist at the University of Cambridge in England. To try to quantify how many humans there were in relation to Neanderthals, Mellars and doctoral student Jennifer French looked at evidence from a region in France known for its abundance of human and Neanderthal sites.
They identified three factors as indicators of population size: the number of dwelling sites, the size of those areas and the densities of stone tools and food remains. The human sites were two to three times larger, and 2.5 times more numerous. And the human sites were 1.8 times more densely populated because their inhabitants left more tools and food remains per square meter of soil than the Neanderthals did.
-- Los Angeles Times