Synthetic rewriting technologies in mammalian cells

Synthetic rewriting technologies, encompassing large-scale DNA assembly, transfer, maintenance, and rearrangement, enabled de novo synthesis or large-scale modifications of genomes. While significant progress has been made in model organisms of viruses, bacteria, and unicellular eukaryotes, their development in mammalian cells faces unique challenges. This review summarizes key breakthroughs in synthetic rewriting technologies, including megabase (Mb)-scale assembly of human DNA, yeast-mediated transfer methods, bottom-up human artificial chromosomes (HACs), and genome-scale rearrangement, along with emerging applications in constructing models and decoding genomes for mammals. These tools will expand functional engineering in mammals and deepen mechanistic insights into complex biological systems.