Cell lineage studies using retroviruses.

In order to study cell lineage in any given experimental situation, a method by which a label can be introduced into a precursor cell is required. By means of this label, the subsequent fate of the cell and its progeny can be followed. A retrovirus, as an agent of gene transfer, can be used as a genetic label, providing an indelible, heritable marker of lineage. Unlike most artificial means of gene transfer, the use of retroviruses in transferring genes into cells is both efficient and accurate. This has made retroviruses invaluable in studying cell lineage in vivo, particularly in mammalian embryos, which are too small and inaccessible to be amenable to study with conventional lineage labels.