Figure 1.

Prospective DNA barcoding strategies. (A) Conceptual illustration of lineage tracing: Cells can be permanently labeled and inherited by offspring cells, markers on labeled cells become increasingly diluted with subsequent divisions, or cells can be cumulatively labeled and recorded over time. (B) Lentivirus integration barcoding: The DNA barcode sequence is inserted into the 3′ UTR of the GFP reporter gene and packaged into a lentiviral vector. Cells of interest are transduced and labeled with a unique DNA sequence through either one-time labeling (left) or continuous labeling over time (right). (C) Cre-recombinase-based barcoding: Cre recombinase recognizes the LoxP site on the introduced gene, then recombination results in inversion or deletion of the DNA sequence of the LoxP site depending on the orientation of these sites. (D) CRISPR–Cas9-based barcoding: During cell differentiation, Cas9 induces double-strand breaks, and incomplete nonhomologous end joining (NHEJ) repair leads to the generation of barcode insertions and deletions over time, serving as a valuable tool for lineage tracing.