Cloning Plant Cells
Not all aspects of the genetic engineering of plant cells are about changing what they look or do. It also is cloning the plants. What image does the word cloning conjure up in your mind? Jurassic Park with its labs full of cloned dinosaur? News headlines about cloned kittens and cloned monkeys? Star Wars and Attack of the Clones? Or even – cloned human beings? Cloning has had a lot of sensational media coverage.
This is where cloning plants started and how it works. The oldest types of genetic engineering occurred on farms, where most people on earth lived at the time. The farmers saved the best apples seeds for the next plantations. While researchers working with animal cells can choose among a wide variety of cloning vectors, plant cell researchers are currently limited to just a few basic types of vectors. Perhaps the most commonly used plant cloning vector is the "Ti" plasmid (tumor-inducing plasmid). This plasmid is found in cells of the bacterium which normally lives in soil. The tumor-inducing capacity of this bacterium results from the presence of the Ti plasmid. The Ti plasmid itself is a big double-stranded DNA molecule. When these bacteria infect a plant cell, 30,000 base-pair segments of the Ti plasmid - called T DNA - separates from the plasmid and incorporates into the host cell. This aspect of Ti plasmid function has made it useful as a plant cloning vector.