Rearrangement of chromosome spatial organization in mouse zygotes using optical tweezers does not affect preimplantation development

The spatial arrangement of chromosomes is thought to influence key processes such as gene expression or chromosome segregation. However, the contribution of chromosome spatial organization in physiological contexts remains disputed. Here, we use optical tweezers to displace nucleoli and physically rearrange the nuclear contents of mouse zygotes. Monitoring the preimplantation development of zygotes with physically shuffled nuclei reveals that cell dynamics, gene expression and overall blastocyst formation are not affected. This suggests that in mouse zygotes, the spatial organisation of chromosomes is not critical for blastocyst development.