1: Bacterial genomes take the form of rings of DNA. An artificial genome is designed on a computer, including a sequence that "watermarks" the genome (red arc) and one that confers resistance to antibiotics (yellow arc). The genome is then synthesized as 1,078 overlapping DNA fragments.
2: Yeast cells stitch together 10 sequential fragments at a time. The longer strands that are produced are in turn stitched together by other yeast cells, and the process is repeated until copies of the whole genome are assembled.
3: The synthetic genomes are added to a colony of bacteria. Some of the bacterial cells entering the process of division absorb the synthetic genomes alongside their own.
4: When the bacterial cells divide, each daughter inherits one genome. An antibiotic is used to kill cells with the natural genome, leaving a colony of bacteria with the synthetic genome. Credit: Bryan Christie Design