When the human genome was fully mapped in 2003, researchers around the globe began to dissect the genome's 3 billion-plus base pairs for the root causes of diseases like Alzheimer's and common cancers. But that was only the beginning. The real dream of biotechnology is not only to understand how our DNA expresses itself, but also to "write" new DNA that heals disease and repairs bodies from the inside out. J. Craig Venter, the bio-entrepreneur whose company helped map the genome, reached a new milestone in 2010 when he built the world's first synthetic, self-replicating chromosome [source: Hessel]. He loaded some homemade synthetic DNA into a bacterial cell and watched it grow and divide according to computer-generated As, Ts, Gs and Cs. By his own reckoning, he had created "life."
In the happy scenario, biologists of the near future will figure out how to program viruses and bacteria to deliver custom-made cures that shrink cancerous tumors or reverse the tide of dementia. In the super scary scenario, bioterrorists engineer deadly superbugs that target us at a genetic level. In a 2012 article, The Atlantic imagined a technologically plausible scheme in which the president of the United States is assassinated by a highly contagious cold designed to target a weak link in his specific genetic code [source: Hessel]. To keep your DNA out of enemy hands, it's best not to leave the house without a hairnet and rubber gloves.