The genome of the pathogenic bacterium Mycoplasma genitalium has been stitched together from scratch, creating a full set of instructions to make a living thing in the lab.

Hamilton Smith and his colleagues at the J. Craig Venter Institute in Rockville, Maryland, put together the 582,970 nucleotide bases ? the building blocks of DNA ? that constitute the M. genitalium genome. The genome is more than a factor of ten longer than the previous longest stretch of genetic material created by chemical means.

Next the team aims to find out whether cells can be 'booted up' into action when loaded with the genetic program.