Beyond the bounds of evolution: Synthetic chromosomes… How and what for?

Chromosome synthesis is still at its early stage. The budding yeast Saccharomyces cerevisiae is an organism of choice with respect to this field, thanks to its efficient homologous recombination pathway. By iteratively concatenating short DNA molecules to ultimately generate large sequences of megabase size, these approaches allow piecing together multiple genes and genetic elements in a way designed by an individual prior to their assembly. They therefore hold important promises as a tool to design complex genetic systems or assemble new genetic pathways that allow addressing fundamental and applied questions. The constant drop in DNA synthesis costs, fed by the development of new technologies, opens new perspectives with respect to the conceptual way these questions can be addressed. Thanks to its properties, S. cerevisiae may provide solutions for chromosome synthesis in other organisms, in combination with genome editing techniques.