ABSTRACT

Conditional gene knockout (CKO) is a new technique that allows researchers to conditionally knock out the expression of the gene of interest in speci„c cell-, tissue-, or organ-type and/or at speci„c development stages, namely, “temporal and spatial knockout,” which is particularly important when investigating the biology of some lethal genes. A lethal gene means that its expression during development can result in death of the animals bearing the lethal gene. Therefore, conditional gene knockout confers advantages over the conventional type in that genetically and conditionally modi„ed mice are not only able to survive but also that these genes-to be scienti„- cally precise-can be “turned on/off.”