The technology works on the principle of recording continuous and accumulative mutations at a target site introduced by CRISPR mediated DNA breaks and subsequent error prone repairs. The power of the technology comes from using self-targeting guide RNA (stgRNA) generated by adding PAM sites to guide RNA. Error prone repair of CRISPR mediated cleavage results in changes in the sequence of stgRNA. If the PAM site is maintained, this process is repeated multiple times for continuous accumulation of mutations.
This targeted mutagenesis can be operationally linked to a biological event of interest by linking expression of stgRNA or Cas9 to the biological event. Accumulative mutations give information about duration and/or intensity of the signal. A chronological order and lineage of cell division can be established using sequencing analysis on this population of cells.