sequential lineage tracing studies aimed at unraveling the relationships between cellular precursors and mature cell types

in the absence of tamoxifen, it exhibits some activity

A technique common in rodents is the use of Cre recombinase lines that are inducible at specific developmental time points (Figure 3b). The most common form of inducible Cre is CreERT2, which contains a modified estrogen receptor binding domain that prevents Cre from entering the nucleus in the absence of a ligand

strong promoters capable of driving expression of microbial opsins or fluorescent proteins in specific populations can exhibit leaky expression elsewhere. This low-level leak may be virtually undetectable as light responsiveness or fluorescence but can be a serious issue when expressing Cre recombinase.

using recombinases can be challenging because their reactions are slow (requiring 2–6 h) and often generate mixed populations when targeting a multicopy plasmid