Manual for Building Synthetic Eukaryotic Genome Published

A global team of synthetic biologists has distilled more than ten years of research into a Nature Biotechnology paper that documents how they constructed the world’s first synthetic eukaryotic genome. Their account offers practical lessons that could speed progress in designing future engineered organisms, from cell factories to resilient crops.

The Synthetic Yeast Genome Project (Sc2.0) united over 200 researchers from more than ten institutions who aimed to redesign and chemically synthesize all 16 chromosomes of baker’s yeast. Macquarie University scientists contributed to two chromosomes—around 12 percent of the total. Each synthetic chromosome followed shared design principles: removing unstable genetic regions, inserting “watermarks” to distinguish artificial sequences, and embedding a system known as SCRaMbLE that allows researchers to rearrange genes and study their effects.

Unlike conventional genetic engineering, which modifies existing DNA, the Sc2.0 consortium reconstructed the yeast genome entirely from the ground up—spanning 12 million base pairs. “Completing all 16 synthetic chromosomes lets us understand genome function at a scale that was simply impossible before,” said co-author Ian Paulsen from Macquarie University. Yeast’s own cellular machinery was used to incorporate large fragments of synthetic DNA step by step into its chromosomes.

As the effort progressed, every participating team faced technical setbacks. Some watermarks unexpectedly disrupted genes, while certain deletions caused cells to weaken or stop growing. Because yeast cannot regenerate its mitochondrial genome, researchers often had to carry out genetic rescue operations, repairing damage and transplanting healthy mitochondria through selective breeding. These collective hurdles led to innovative problem‑solving tools such as Pooled PCRtag Mapping—allowing high‑throughput screening of yeast colonies—and CRISPR D‑BUGS, which combines genome editing with selection tests to locate and fix errors.

“The hardest challenges were both psychological and technical,” said co-author Hugh Goold. “The long haul of a decade‑long project where progress could feel painfully slow, and the difficulty of working with cells that were unfit and difficult to grow.”

Insights from yeast are already guiding new frontiers. Macquarie researchers are now constructing the first synthetic crop chromosome. Built initially in yeast before being transferred to plants, the project marks the next step in applying Sc2.0’s lessons. “Putting all the synthetic DNA into a single cell will be a momentous occasion,” said Goold.