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The Mystery of the Coca Plant That Wouldn't Die
...Over the past three years, rumors of a new strain of coca have circulated in the Colombian military. The new plant, samples of which are spread out on this table, goes by different names: supercoca, la millonaria. Here in the southern region it's known as Boliviana negra. The most impressive characteristic is not that it produces more leaves - though it does - but that it is resistant to glyphosate. The herbicide, known by its brand name, Roundup, is the key ingredient in the US-financed, billion-dollar aerial coca fumigation campaign that is a cornerstone of America's war on drugs.

One possible explanation: The farmers of the region may have used selective breeding to develop a hardier strain of coca. If a plant happened to demonstrate herbicide resistance, it would be more widely cultivated, and clippings would be either sold or, in many cases, given away or even stolen by other farmers. Such a peer-to-peer network could, over time, result in a coca crop that can withstand large-scale aerial spraying campaigns.

But experts in herbicide resistance suspect that there is another, more intriguing possibility: The coca plant may have been genetically modified in a lab. The technology is fairly trivial. In 1996, Monsanto commercialized its patented Roundup Ready soybean - a genetically modified plant impervious to glyphosate. The innovation ushered in an era of hyperefficient soybean production: Farmers were able to spray entire fields, killing all the weeds and leaving behind a thriving soybean crop. The arrival of Roundup Ready coca would have a similar effect - except that in this case, it would be the US doing the weed killing for the drug lords.

Whether its resistance came from selective breeding or genetic modification, the new strain poses a significant foreign-policy challenge to the US. How Washington responds depends on how the plant became glyphosate resistant. That's why I'm here in the jungle - to test for the new coca. I've brought along a mobile kit used to detect the presence of the Roundup Ready gene in soybean samples. If the tests are inconclusive, my backup plan is to smuggle the leaves to Colombia's capital, Bogotá, and have their DNA sequenced in a lab.

In my hotel room, I put the swizzle stick-sized test strip into the tube filled with mashed Boliviana negra. The green water snakes up the strip. If the midsection turns red, I'll know that the drug lords have genetically engineered the plant and beaten the US at its own game. If it doesn't, it'll mean that Colombia's farmers have outwitted 21st-century technology with an agricultural technique that's been around for 10,000 years....

...Four weeks later, the scientist sends me an email saying that he has completed the DNA analysis and found no evidence of modification. He tested specifically for the presence of CP4 - a telltale indicator of the Roundup Ready modification - as well as for the cauliflower mosaic virus, the gene most commonly used to insert foreign DNA into a plant. It is still possible that the plant has been genetically modified using other genes, but not likely. Discovering new methods of engineering glyphosate resistance would require the best scientific minds and years of organized research. And given that there is already a published methodology, there would be little reason to duplicate the effort.

Which points back to selective breeding. The implication is that the farmers' decentralized system of disseminating coca cuttings has been amazingly effective - more so than genetic engineering could hope to be. When one plant somewhere in the country demonstrated tolerance to glyphosate, cuttings were made and passed on to dealers and farmers, who could sell them quickly to farmers hoping to withstand the spraying. The best of the next generation was once again used for cuttings and distributed.

This technique - applied over four years - is now the most likely explanation for the arrival of Boliviana negra. By spraying so much territory, the US significantly increased the odds of generating beneficial mutations. There are numerous species of coca, further increasing the diversity of possible mutations. And in the Amazonian region, nature is particularly adaptive and resilient.

"I thought it was unlikely," says Gressel, the plant scientist at the Weizmann Institute. "But farmers aren't dumb. They obviously spotted a lucky mutation and propagated the hell out of it."

The effects of this are far-reaching for American policymakers: A new herbicide would work only for a limited time against such a simple but effective ad hoc network. The coca-growing community is clearly primed to take advantage of any mutations....