Summary - Transformation
- Transformation is when a new gene (transgene) is delivered into the nucleus of a plant cell and inserts into a chromosome where it is passed on to progeny.
- Transformation is typically done on callus cells (tissue culture) but is occasionally done to other plant parts, such as germline cells or pollen.
- The four main methods of transformation are:
- Gene gun - shoots gene-coated gold particles at cells
- Agrobacterium - a natural genetic engineer that inserts a portion of the Ti plasmid containing a transgene
- Whiskers - gene-coated needles that stab the cell
- Electroporation - Pulses of electricity open pores in the cell wall allowing genes to pass into the nucleus
- The goals of the transformation process are:
- Deliver many copies of the gene(s) into the nucleus without killing the cell
- At least one transgene copy must insert into a chromosome (can't be controlled by the geneticist)
- Transgenic cells must replicate their chromosomes and divide, passing the transgene on to progeny
- There must be a way to easily identify and select the transgenic cells from non-transgenic cells (use of a selectable marker gene)