Plant Breeding
To tell the truth, most of the plants around us including edible plants and decorative plants have been artificially improved in some ways. The purposes of plant breeding are various; For vegetables, the purpose could be to improve the taste, or to make the vegetables tolerant for pests. For decorative plants, the purpose could be to generate beautiful colors or new colors. And, the methods also are various.
Cross-breeding
The method of cross-breeding includes putting pollens of some plant to a pistril of another plant, artificially.The result of this method is limited.
Even in case of human or animals, we can not expect which part of the baby will take after his/her mother or father. It is the same in case of plants, and it is not always possible to generate ideal features by cross-breeding.
Moreover, it is impossible to make a mix of human and a cat, and it is impossible as well to make a mix of different spieces of plants.
Then, the technology of genetic exchange has been developed.
Genetic Exchange
Genetic exchange is the method to exchange the genes of some plant with the genes of another plant, artificially. This technology has resolved the problems, which could not be resolved only by cross-breeding methods. It made it more certain to generate ideal features, and even it made it possible to add features of some plants (even animals) to another spieces of plants.The methods are explaind in the following sentences.
Agrobacterium
Agrobacterium is the bacterium, which intrudes inside the plants and causes the infection. With taking advantage of such feature as "intruding inside the plants", this method makes it possible to exchange the genes of some plant with another genes with ideal features.
1) Cut a part of the gene (blue part of the figure) of agrobaceria with using enzyme, and exchange it with another gene (red part of the figure).
2) Attach the agrobacteria with the new gene to the plant, of which the new feature is wanted.
3) The agrobacteria intrude inside the plant, and the gene is exchanged.
Electro-Poration
1) Isolate protoplasts, which is the cells with which the cell wall is removed, from the plant.
2) Put these protoplasts and another genes in the same solution, and give it a electric shock.
3) The electric shock makes small holes on the surface of the protoplasts, and it enables the genes to go inside the protoplasts.
4) Cultivate these protoplasts to make the plant with new genes.
Particle Gun
1) Attach the genes on the particles made with gold and so on.
2) Shoot the plant with particles with genes with strong pressure.
If Genetic Exchange is Safe or Not?
The answer for this question has not been clarified at this moment.First of all, let us think of vegetables, which are commonly eaten. People in our generation like vegetables less bitter or less astringent, and easy to cook and eat. To produce such vegetables, people have made efforts with using cross-breeding method among various kind of breedings.
However, tasty vegetables for people also are tasty for bugs. Vegetables used to have bitter or astringent ingredients to protect themselves from the pests, however these features have been sacrificed by people.
Then, people thought of the method to use pesticide to kill the bugs. However, it is needless to say that pesticide is toxic for human.
Therefore, people have developed the technology of genetic exchange, to produce the vegetables with features to keep the bugs away or decompose the pesticide, with keeping the good taste. Such vegetables are called "genetically exchanged vegetables".
Which is safer, vegetables covered with pesticide or genetically exchanged vegetavles? The answer for this question is still unknown, however there is no way to predict the future risk of genetically exchanged food, even if they are safe to be eaten once or twice. We are not sure what will happen if we keep eating genetically exchanged food for tens of years because this technology has been developed just recently, while pesticides have been used for a long time.
By the way, do you feel like growing true red daffodils or true blue tulips, produced by genetic exchange? I feel somewhat resistance for them.
