Providing the world's population with food -one of the most important and most acute contemporary problems. Suffice it to recall that approximately 12% of the world's inhabitants suffer from a lack of nutrition, and about a billion people are chronically starving. The removal of new highly productive varieties of plants and the creation of breeds of farm animals can help in solving this problem. It is precisely these tasks that breeding is doing. In this article, we will review its main methods, and also find out what are the relationships between artificial selection and selection of animals, plants and microorganisms.
Modern selection and its tasks
Feed the population of the country - the main prioritypractical science engaged in increasing the productivity of modern varieties and breeds, as well as creating new forms of them that are designed to meet the pressing needs of both agriculture and various industries of the food industry. As emphasized by the great Russian genetic scientist NI Vavilov, the study of the peculiarities of the relationship between artificial selection and selection is extremely necessary for selecting the desired shape, as well as for hybridization. NI Vavilov attached special importance to the diversity of genotypes of individuals serving as the basis for selection experiments. Another important task facing science is the protection of the genetic material of wild plant and animal species whose genotypes serve as a repository of valuable traits and properties.
Charles Darwin and his teachings on artificial selection
To understand what the relationship betweenartificial selection and selection, let's see what is the artificial selection itself and what is its role in breeding new breeds of domestic animals and varieties of cultivated plants. Recall that Charles Darwin identified artificial selection as a kind of human activity, directed both unconsciously and with a specific purpose to preserve the most productive individuals and obtain from their crossing a large number of descendants. The methodological form of artificial selection is currently one of the main tools in the arsenal of breeders-practitioners.
It is sad, but the properties and signs,selected as useful and necessary for humans, in most cases are indifferent and even harmful to most plants or animals. Living organisms become hostages to the needs and whims of man. For example, the well-known Dutch breed of cattle, which gives up to 14,000 liters of milk per year, can not exist without special forages and careful care. Another example: the chicks of tumblers - the decorative breed of pigeons - are not able to penetrate the eggshell themselves, because as a result of artificial selection the length of the beak of birds is greatly reduced, but their ability for complex somersaults during the flight, on the contrary, has become very high. In addition, it was found that the decrease in the viability of both plant and animal organisms is correlatively associated with an increase in the modification variability of organisms.
Forms of artificial selection and their effectiveness
Continuing to consider the question, what is the relationshipbetween artificial selection and selection, let us consider two of its forms: individual and mass. The first of them gives the best practical results, as for the research individual individuals with the most promising genotypes and external traits are left. The gene pool of such organisms is determined using the genealogical method, as well as analyzing and recurrent crosses. Mass screening is less promising due to some drawbacks, for example, a group of phenotypically homogeneous individuals may turn out to be both homo- and heterozygous. Crossing the latter among themselves, the breeder can first achieve a rapid manifestation of the desired traits, but in the course of further crossings, there will be an increase in the frequency of occurrence of homozygous individuals, which leads to a decrease in the breeding performance.
Selection Results
Individual, as well as mass artificialselection and selection can use the results of both forms of variability: both mutational and modification. This allows scientists to create breeds and varieties with pre-expected attributes and properties. Specially selected parental pairs, to which various forms of hybridization are applied, ensure the appearance of offspring with predictable phenotypic traits.
Differences of artificial selection from breeding
Considering the methods of breeding new breeds andvarieties used by researchers, it is possible to trace common features, namely the use of unrelated crossing and the phenomenon of heterosis, as well as analyzing forms of crossing. This suggests that artificial selection and selection are the same. In fact, such selective techniques as, for example, induced mutagenesis, reciprocal crossing, gene transfer, biotechnological methods, are much more complex and broader than the methods of artificial selection.
These types of breeding work lead to the emergence ofpreviously non-existent genetically modified organisms, whose properties are several orders of magnitude higher than those of existing biological species. For example, genetically modified potato varieties whose genomes contain DNA molecules isolated from chromosomes from the Colorado potato beetle are resistant to many pests and are not affected by phytophthora.
Variety of initial forms is the basis of selection work
Familiarity with the seven regions of the Earth, which arecenters of origin and domestication of agricultural plants and animals, helps in clarifying the issue of the relationship between artificial selection and selection. An extensive collection of seeds (about 1600 plant species), collected in the expeditions of Academician N. Vavilov, is still the main selection material used by scientists of different countries in practical work on the development of new varieties with unique characteristics. It should be noted that all the centers of origin of cultural forms are geographically and historically connected with the first human civilizations that were engaged in agriculture and cattle breeding in those days.
Practical application of selection results
Joint efforts of international breedingorganizations and research institutes, a large number of new varieties, breeds and strains have now been bred, and organisms that had not previously inhabited the Earth were created. For example, by a method of remote hybridization, a cabbage and rape hybrid was created, called rape. Currently, this is one of the main plant-honey plants. It is also widely used as a valuable green feed.
Let's not forget that the creation of newselection methods are artificial selection. Selection, an example of the results of which we mentioned earlier, contributed to the development of such promising industries as gene and cellular engineering, as well as biotechnology. More than four thousand varieties of wheat, about eight thousand forms of tulips, 25,000 varieties of basic food plants: rice, potatoes, corn, sunflower - the real contribution of selection to the development of world food production.
Biotechnology and its role in the national economy
This branch of science as the basis for its ownresearch also uses artificial selection. The selection of microorganisms was previously conducted by man unconsciously and was used mainly in bakery, in the technology of wine and cheese production. In the 20th century, called the era of antibiotics, the biotechnology of microorganisms began to be widely used to derive highly productive strains that produce penicillin and its derivatives. At present, a great prospect opens for the removal of strains of fungi, algae and protozoa, capable of biological purification of water and soil.
In this article, we found out the relationship between artificial selection and selection, and also determined their role in the fight against food shortage in the population of our planet.
