Transposon tagged alleles are caused by insertion of a transposable element. Fortunately, some researchers are willing to share their large collections of transformants with their colleagues, so that different teams can search one collection for a variety of mutant phenotypes. In practice, the transposable element is mobilized by crossing a plant containing the transposon with a second plant lacking the transposon. Once a T-DNA has integrated, it doesn't move again. Therefore, T-DNA tagged alleles are stable.
Transposable elements have the tendency to jump to closely linked sites .
Therefore, one can improve the chances of tagging a specific gene of interest by starting with a transposable element at a closely linked donor site. 3.2 Finding and confirming a tagged allele After obtaining a collection of plants with random insertion events, one screens for the phenotype of interest. Unfortunately, not all mutant alleles will be associated with the tag. Therefore, it is essential to confirm by segregation analysis that the mutant phenotype is tightly linked with the tag. The check may involve Southern blot hybridization with the tag as a probe, or, easier, screening plants for a resistance marker on the tag.