GOING BANANAS
PARIS
The commercial banana has such a narrow genetic base that it could be wiped out within a decade by two fungal diseases.
The alarm, published in New Scientist, was sounded by Belgian plant pathologist Emile Frison, researcher at INIBAP, a worldwide network of banana specialists.
New Scientist says the problem with the banana eaten around the world today is that it is drawn from a tiny gene pool. "That uniformity makes it ripe for disease like no other crop on earth," it warns.
Just one variety-Cavendish-accounts for almost all of the bananas sold today. Cavendish, like other commercially-grown bananas, is a genetic freak.
In its wild form, the banana is almost inedible. It is riddled with stony seeds. The theory goes that early hunter-gatherers must have stumbled across rare mutant plants that produced seedless, edible fruit-the forefather of today's. These soft-fruited plants are the result of a genetic accident that gives their cells three copies of each chromosome instead of two. That imbalance prevents seeds and pollen from developing normally, making the mutant plants sterile.
Traditional varieties of sexually reproducing crops have a broader genetic base, in which genes swap and recombine in each new generation, and the new configurations offer a better chance against disease.
Bananas, though, have no such defenses. They are under attack on two fronts.
The first threat is a fungal disease called black Sigatoka, which has become a world epidemic and is swiftly developing resistance to chemicals. The other is a new form of relentless soil fungus called Panama disease that 40 years ago wiped out the then dominant variety Gros Michel.
Efforts to come up with a new variety have failed because all the edible varieties are vulnerable to the two diseases. The Honduran Foundation of Agricultural Researchers succeeded in creating a seedless variety resistant to both kinds of pest-but it tasted more like an apple.
An option is genetic modification: to make a variety of disease-resistant edible bananas. Ecologists are strenuously against genetically-modified crops, saying their impact on health and the environment are still unknown.
But bananas might be considered an exemption, given its importance and the fact that bananas are sterile, which reduces the risk that the inserted genes could spread to other species.
AFP
END OF THE UNIVERSE
PARIS
The bad news: The universe will end in a runaway expansion so violent that galaxies and planets will be torn apart and individual atoms of human flesh will be ripped asunder in the tiniest fraction of a second.
The good news: It won't happen for another 22 billion years.
Robert Caldwell, physicist at Dartmouth College, New Hampshire, says the doomsday scenario inverts the widespread belief that the cosmos will end with a whimper. "Until now we thought the universe would either recollapse to a big crunch or expand forever to a state of dilution," he said. "Now we've come up with a third possibility-the big rip."
The universe is famously believed to have been born in a "Big Bang" 12 to 14 billion years ago and has been expanding ever since, driven by a mysterious force known as dark energy.
According to Caldwell's theory, the dark energy-he calls it "phantom energy"-may be becoming more powerful, acting as a foot on the expansion accelerator. The universe would be stretched further and further away, until the light of the stars could not reach us. Eventually, phantom energy would tear apart all bound systems, sundering the electrical bonds that hold matter together.
In the most extreme scenario, the "big rip" would happen 22 billion years from now, with the Milky Way destroyed 60 million years earlier. "In the last moments, even atomic nuclei will be ripped apart," Caldwell said.
AFP
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