New genome-editing tools trace mouse embryo cell lineages

Researchers have utilized two distinct genome-editing technologies, DNA Typewriter and PEtracer, to map the cellular lineages of developing mouse embryos. These studies, published in Cell and Science, provide a detailed chronological record of how a single fertilized egg divides and differentiates into a complex organism.

The DNA Typewriter method, developed by scientists at the University of Washington, uses CRISPR-based prime editing to ‘stamp’ genetic barcodes onto a cell’s DNA. This creates a permanent, sequential record of cell divisions from the zygote stage up to 13.5 days of development, tracking over 1.3 million cells. This technology could eventually help researchers understand the origins of congenital defects, neurodevelopmental disorders, and cancers.

In a parallel study, a team from the Whitehead Institute at MIT and the Max Planck Institute for Molecular Genetics used the PEtracer technique. This method introduced heritable genetic marks to resolve approximately 75 percent of cell divisions across more than 1.4 million cells from 16 mouse embryos between days 7.5 and 10 of gestation. Together, these advancements offer new insights into the mechanisms of mammalian embryogenesis.