There are different conceptions of what counts as a synthetic cell, but in this work the DNA is indeed synthetic. They designed their desired genome sequence on

There are different conceptions of what counts as a synthetic cell, but in this work the DNA is indeed synthetic. They designed their desired genome sequence on a computer, and synthesized the DNA by chemically printing it into segments, and then assembling those segments together into a complete genome. There are commercial providers that will synthesize DNA from sequence information [1]. The actual design itself was heavily based on the genome of a natural organism, M. mycoides. They sequenced its genome and built an experimental dataset of which genes were essential and which weren't, then designed and printed a genome using the native sequences of just the essential genes. Work on synthetic cells is now moving in a few directions, including designing the genome from scratch and building cellular or cell-like chassis to 'run' the genome. [2] Even in designing a genome from scratch, however, we would still be using proteins sourced from nature, because our ability to design proteins is still very limited. One way to think of this is that the biological world provides a massive pre-designed parts catalogue, and then we can compose those parts in a synthetic genome. I'm a graduate student working on building a cell [3], happy to answer any other questions you might have. [1] Like Twist, https://twistbioscience.com/ https://twistbioscience.com/ [2] https://www.nature.com/articles/d41586-018-07289-x https://www.nature.com/articles/d41586-018-07289-x [3] http://buildacell.io http://buildacell.io