Researchers from the Scripps Research Institute in La Jolla, Calif., created a semi-synthetic microbe, a genetically modified E. coli bacterium. They created two new nucleotides, X and Y, and fused them into the E. coli bacterium. The E. coli bugs grew and reproduced normally but with six -- instead of the standard four -- nucleotides, meaning it genetically passed along the first combination of manmade and natural DNA. Potential uses of the technology include the incorporation of a toxic amino acid into a protein to ensure that it kills only cancer cells.
Read more in Nature.