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"  The pathogen Phytophthora infestans, born in the Toluca Valley in central Mexico, where it latched on to a white potato heading for Europe, is responsible for starving one million people during Ireland&amp;#039;s Great Famine in the mid-1800s. Within months, this microbe was wreaking havoc on Ireland&amp;#039;s potato production. Today it can still cause blights costing billions of dollars in lost food per year. Scientists think they have finally found the Achilles&amp;#039; heel of this notoriously resistant organism. &amp;quot;It has a dramatic ability to target new plants and be resistant,&amp;quot; says Sophien Kamoun, who led the research behind the paper published in the December 10 issue of Science. His team was surprised to discover that the bacterium&amp;#039;s genome has two very distinct regions that evolved at different speeds. One region consists of tightly packed genes that mutate very little over time. The other contains sparsely populated, fast-changing genes that affect a plant&amp;#039;s immune system. The remarkable flexibility\u2014and hardiness\u2014of the plant killer, Kamoun believes, is due to this two-speed behavior. In order to understand how Phytophthora infestans evolves so quickly to feed off of new organisms, Kamoun&amp;#039;s team went to the Toluca Valley in central Mexico to find and study the bacterium&amp;#039;s relatives. They identified and sequenced the genome of microbes that affect both wild and farmed tomatoes and potatoes, as well as lima beans and morning glory and four o&amp;#039;clock flowers. Although they survive off completely different plants, the highly destructive species share 99.9 percent of the genetic code. The difference in structure occurs in those areas where the pathogen had to evolve quickly to survive in a new host. This portion of the code\u2014which contains more scattered, adaptable genes\u2014has a lot of repetitive DNA, sometimes referred to as junk DNA, because it doesn&amp;#039;t appear to have any biological function. The slowly evolving region has genes responsible for housekeeping tasks such as spore production, which helps the species spread. It&amp;#039;s in this region, the researchers now think, that they found the microbe&amp;#039;s weak spot. Because that area is slow to adapt to new environments, targeting tasks that are controlled by this region could kill off the organism, since it won&amp;#039;t be able to quickly adapt. This new understanding of Phytophthora infestans explains why it&amp;#039;s been a difficult pest to manage and why it continues to kill crops 150 years after the Irish Potato Famine. With this new knowledge, food scientists may be able to create crops that are more resistant to the bug. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/health/a12410/irish-potato-famine-genome-cure-4241783/>