Biotech: How can it stay safe?

Genetically modified microbes could herald a new industrial revolution - but the technology also poses new dangers. Manuela Saragosa speaks to someone who used it to recreate the horsepox virus - a close cousin of smallpox - from scratch three years ago. Virologist David Evans explains why he did it, and what aspects of this rapidly evolving technology worry him most. One of the companies on the cutting edge is Boston-based Ginkgo Bioworks. It redesigns the DNA of bacteria and yeast in order to create everything from perfumes to fertilisers. Ginkgo's Patrick Boyle tells Manuela what they are doing to ensure that the microbes and DNA they create remain harmless. Producer: Laurence Knight (Picture: Anonymous vial containing a clear liquid; Credit: MirageC/Getty Images)