What is the relationship between artificial selection and selection? Artificial selection and selection: an example

Providing the world's population with food is one of the most important and most acute modern problems. Suffice it to recall that about 12% of the world's inhabitants suffer from a lack of nutrition, and about a billion people are chronically starving. The withdrawal 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

Feeding the population of the country is the main priority of practical science engaged in increasing the productivity of modern varieties and breeds, as well as creating new forms of these that are designed to meet the pressing needs of both agriculture and various branches of the food industry. As stressed 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 attributes and properties.

Charles Darwin and his teachings on artificial selection

To understand the relationship between artificial selection and selection, let's look at what is 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 purpose to preserve the most productive individuals and to obtain from their crossing a large number of descendants. 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 chosen as useful and necessary for a person, in most cases are indifferent and even harmful for the most plants or animals. Living organisms become hostages to the needs and whims of man. For example, the well-known Dutch breeds of cattle, which produce 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 unable 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 has been established that a decrease in the viability of both plant and animal organisms is correlated with an increase in the modification variability of organisms.

Forms of artificial selection and their effectiveness

Continuing to consider the question, what are the relations between 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 single 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 shortcomings, 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 artificial selection 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 in artificial selection from breeding

Considering the methods of breeding new breeds and varieties 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 methods 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 appearance of previously 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 are centers 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 the 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 territorially and historically connected with the first human civilizations, engaged in those ancient times in agriculture and cattle breeding.

Practical application of selection results

By joint efforts of international breeding organizations 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. At present, this is one of the main plants-melliferous plants. It is also widely used as a valuable green feed.

Let's not forget that artificial selection is the basis for creating new breeding methods. Selection, an example of the results of which we mentioned earlier, contributed to the development of such promising industries as gene and cell 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 also uses artificial selection as the basis for its research. 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 develop 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 that are 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.