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Genetic improvement and artificial selection
For centuries man has used the practice of genetic improvement to perfect animal and plant species of interest.
It all began when man began to cross, followed by artificial selection, the varieties that interested him most. This procedure has given rise to countless animal breeds and plant varieties that are now part of our daily lives. Horses and donkeys are crossed to produce hybrids - mules and donkeys - used for traction services; Dairy and beef cattle are much more productive today than in the past; Plants such as corn, beans and soy currently produce grains of excellent nutritional value.
In order to preserve the qualities of the numerous plant varieties obtained at crosses, man learned to make vegetative propagation, a process performed mainly by planting pieces of stem (stake) or grafts (grafting) of good quality plants.
This kind of Asexual reproduction forms clones of plants with better characteristics.
Good examples of this process are the cutting, currently practiced by the São Paulo Forestry Institute, of eucalyptus twigs in the propagation of excellent quality wood-producing varieties for house building, and the grafting of numerous orange varieties, among them. bay orange, also known as navel orange.
We have seen that since ancient times man has learned through observation and experimentation to practice the breeding of animal and plant species of some economic, food or medicinal interest. These foundations started a technology known as biotechnology, which can be defined as a set of techniques that use living organisms or parts of them to produce products or processes for specific uses. Looking at the definition, we may think that biotechnology has been practiced by man for thousands of years, when he learned to use, for example, fermenting microorganisms for the production of bread, yogurt and wine.
After understanding the structure of DNA in the 1950s and understanding its process of duplication and participation in protein production, a strand of biotechnology known as genetic engineering, which, through DNA manipulation techniques, allows the selection and modification of living organisms in order to obtain products useful to man and the environment.
With Watson and Crick's elucidation of the structure of the DNA molecule in 1953 and the recognition that it was the main constituent of genes, the great challenge for scientists was to make a detailed analysis of its composition in the various living things. It was also known that the adenine, thymine, cytosine and guanine nitrogen bases, components of nucleotides, were related to the process of the genetic code that commanded protein production. But several questions still troubled scientists: where does a gene start and end? What is your nucleotide sequence? How many genes are there in each species of living being?
The search for answers to these questions has generated intense research work and originated one of the most promising and spectacular branches of current biology: genetic engineering.
The manipulation of genes resulting from research has led to the need to understand the meaning of new concepts related to this area.
These concepts include restriction enzyme, target sites, gel electrophoresis, recombinant DNA technology, PCR technique, DNA library, probes, fingerprint etc.
One question you might ask is: Why should I know all these concepts and how useful are they for my life? Because for you to have an opinion on GMOs, paternity research, drug and vaccine production, and gene therapy, you need to know what you're talking about. We all hope that research will contribute to improving the well-being of humanity and so we have to know the main techniques used by it to be able to judge them fairly.