One Yeast, Sixteen Synthetic Chromosomes, Infinite Possibilities.

The evolution of the yeast, Saccharomyces cerevisiae, from a genetically tractable model organism to a chassis for genome-scale engineering represents one of the most influential trajectories in eukaryotic biology. The Synthetic Yeast Genome Project (Sc2.0) embodies the current height of this trajectory, having now delivered functional synthetic versions of all 16 native yeast chromosomes and bringing the construction of the first fully synthetic eukaryotic cell within reach. Beyond its technical achievements, Sc2.0 has reshaped how eukaryotic genomes are understood and explored through iterative design-build-test-learn (DBTL) cycles, and reframed the yeast genome as a dynamic, highly modifiable system rather than a static biological blueprint. Moreover, the progress on genome engineering pipelines and synthetic biology has laid the foundations for the de novo development of modular synthetic chromosomes (neochromosomes) that operate orthogonally to the native genome. These synthetic platforms provide dedicated, large-scale genomic landing pads for refactoring genetic networks, reallocating redundancy, and introducing large, multiplexed gene assemblies, thereby extending yeast engineering toward programmable and hyper-versatile biological systems. To commemorate the 40th anniversary of the journal Yeast, this minireview celebrates the exceptional power of yeast genetics, outlining key conceptual and technological advances emerging from the Sc2.0 endeavour and beyond. Finally, we examine the cross-cutting engineering insights and the future potential of neochromosomes for the next generation of synthetic yeasts.