Researchers at the Scripps Research Institute in La Jolla, California, introduced DNA molecules not found in nature to a common bacterium The E. coli bugs are able to grow and reproduce as normal despite containing two extra letters in their genetic code In the future the research could lead to creation of microbes capable of manufacturing entirely new proteins that could be used in medicine Some people are worried that the rapid advance of ‘synthetic biology’ could lead to the worrying prospect of new life-forms escaping from labs The modified E.coli bacteria was made by scientists who introduced DNA molecules not found in nature to a common bacterium.