The methods are based on the isolation of the gene from the genome of the organism and its introduction into the genome of another organism. “Cutting” of genes is carried out by using special “genetic scissors” enzyme – restriction enzyme gene and then sewn into a vector – a plasmid, by which the gene is introduced into a bacterium. Inserting another by means of a group of enzymes – ligases. Moreover, the vector should contain everything you need to control the operation of this gene – promoter, terminator, operator gene and a gene regulator. In addition, the vector should comprise marker genes, which impart to recipient cell novel properties that allow distinguishing this cell from the source cell. The vector is then introduced into the bacterium, and in the last step, those bacteria are selected in which introduced genes work successfully.
A favorite subject of genetic engineers – Escherichia coil, a bacterium that lives in the human gut. It is with its help get growth hormone – growth hormone, the hormone insulin, which is used to get from the pancreas of cows and pigs, the protein interferon, which helps to cope with the viral infection.
The second way – the synthesis of a gene artificially. For this purpose, the mRNA by the enzyme reverse transcriptase on mRNA synthesized DNA.
Chromosome engineering methods
One group of methods is based on introducing into the genotype of a plant organism pair of homologous chromosomes foreign controlling the development of the desired characteristics or a substitution of one homologous chromosome pairs to another. It involves methods of preparing substituted and amended lines in which to gather the plants signs approaching the creation of an “ideal grade”.
A very promising method for haploid production based on the cultivation of haploid plants followed by a doubling of the chromosomes. For example, the pollen grains were grown from the haploid maize plants containing 10 chromosomes, and then double the chromosome to obtain diploid (10 chromosomes), fully homozygous plants for only 2-3 years, 6-8 years, instead of inbreeding. This also can be attributed to obtain polyploid plants as a result of magnification of chromosomes.
Methods for Cell Engineering
- Cultivation of cell cultures. Method involves culturing selected cells in nutrient media, where they form a cell culture. It turned out that the plant and animal cells, placed in a nutrient medium containing all the necessary substances for life, able to share. Plant cells also possess the property of totipotency, that is, under certain conditions, they are able to form a complete plant. This enables using the cell culture to obtain valuable substances. For example, ginseng cell culture accumulating the biologically active substance. On the other hand, these plants can be propagated in the tubes by placing cells in a defined culture media. Therefore, it is possible to propagate rare and valuable plants. This allows the creation of virus-free potato varieties or other plants.
- Hybridization cells. For example, the technique of protoplast hybridization of somatic cells. Removes cell walls and fused protoplasts of cells belonging to different species – potato and tomato, apple and cherry. Promising the creation of a hybrid, in which hybridization is carried out of different cells. For example, cells producing antibodies, which hybridize, with cancer cells. As a result, brings ever hybridoma antibodies as lymphocytes, and “immortal” as cancer cells. Consequently, they are capable of unlimited expansion in culture.
- Cloning. An interesting method of nuclear transfer of somatic cells in the egg. In this way, the possibility of cloning animals to obtain genetic copies of one organism. There is now cloned frogs, the first results of mammalian cloning.
- Creation of chimeric animals. Perhaps fusion of embryos at an early stage in such a way were obtained chimeric mouse embryos at the confluence of the white and black mice, a chimeric animal is a sheep-goat.