Providing the world's population with food is one of the most important and most acute contemporary problems. Suffice it to recall that approximately 12% of the world's inhabitants suffer from malnutrition, and about a billion people are chronically starving. Breeding new highly productive plant varieties and creating farm animal breeds can help solve this problem. It is these tasks that selection is engaged in. In this article we will consider its main methods, and also find out what are the relations between artificial selection and selection of animals, plants and microorganisms.
Modern selection and its tasks
Feeding the country's population is the main priority of practical science, which is engaged in increasing the productivity of modern varieties and breeds, as well as creating new forms that are designed to satisfy the urgent needs of both agriculture and various branches of the food industry. As the great Russian geneticist N.I. Vavilov emphasized, the study of the features of the relationship between artificial selection and selection is extremely necessary to select the desired form, as well as during hybridization. N. I. Vavilov attached a special role to the diversity of the genotypes of individuals that serve as the basis for selection experiments. Another major task facing science is the protection of the gene material of wild species of plants and animals, whose genotypes serve as a repository of valuable traits and properties.
Charles Darwin and his teachings on artificial selection
To understand the relationship between artificial selection and selection, let's look at what artificial selection itself is and what its role is in breeding new breeds of domestic animals and cultivated plant varieties. Recall that Charles Darwin defined artificial selection as a type of human activity, aimed both unconsciously and with a specific goal, to preserve the most productive individuals and obtain from them a large number of descendants. The methodological form of artificial selection is currently one of the main tools in the arsenal of breeders and 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 the 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 thousand liters of milk per year, cannot exist without special feed and thorough care. Another example: chicks of turmans - a decorative breed of pigeons - are not able to independently break through the shell of an egg, because as a result of artificial selection, the length of the beak of the birds was greatly reduced, but their ability to complex flip-flops during the flight, on the contrary, became very high. In addition, it was found 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 of what are the relations between artificial selection and selection, we consider its two forms: individual and mass. The first of them gives the best practical results, since single individuals with the most promising genotypes and external characters are left for research. The gene pool of such organisms is determined using the genealogical method, as well as analyzing and return crosses. The mass selection is less promising due to some drawbacks, for example, a group of phenotypically homogeneous individuals may turn out to be both homo- and heterozygous. By crossing the latter among themselves, the breeder can first achieve a quick manifestation of the desired traits, but in the course of further crosses there will be an increase in the frequency of occurrence of homozygous individuals, which leads to a decrease in the performance of breeding work.
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 predetermined traits and properties. Specially selected parental pairs, to which various forms of hybridization are applied, provide the appearance of offspring with predicted phenotypic characters.
Differences between artificial selection and selection
Considering the methods of breeding new breeds and varieties used by researchers, we can trace common features, namely the use of unrelated crosses and the phenomenon of heterosis, as well as analyzing forms of crosses. This suggests that artificial selection and selection are one and the same. In fact, such selection methods as, for example, induced mutagenesis, reciprocal crossbreeding, transfer of gene material, biotechnological methods, are much more complex and wider than artificial selection methods.
These types of breeding work lead to the appearance of previously unexisting genetically modified organisms, whose properties are several orders of magnitude higher than that of existing biological species. For example, genetically modified potato varieties whose genomes contain DNA molecules isolated from the chromosomes of the Colorado potato beetle are resistant to many pests and are not affected by late blight.
A variety of initial forms - the basis of breeding work
Acquaintance with the seven regions of the Earth, which are the centers of origin and domestication of agricultural plants and animals, helps in clarifying the question of what are the relations 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 breeding material used by scientists from different countries in practical work to develop new varieties with unique traits. It should be noted that all centers of the origin of cultural forms are territorially and historically connected with the first human civilizations engaged in agriculture and cattle breeding in those ancient times.
Practical application of selection results
By the joint efforts of international selection organizations and research institutes, a large number of new varieties, breeds and strains have now been bred, as well as organisms that have not previously lived on Earth have been created. For example, a remote hybridization method created a hybrid of cabbage and colza, called rape. Currently, it is one of the main honey plants. It is also widely used as a valuable green food.
Let's not forget that the creation of new breeding methods is based on artificial selection. Selection, an example of the results of which we gave earlier, contributed to the development of such promising industries as genetic and cellular engineering, as well as biotechnology. More than four thousand varieties of wheat, about eight thousand forms of tulips, 25 thousand varieties of the main 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 carried out by a person unconsciously and was mainly used 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 breed highly productive strains that produce penicillin and its derivatives. Currently, a great prospect opens up for the cultivation of strains of fungi, algae and protozoa capable of biological treatment of water and soil.
In this article, we found out what the relationship between artificial selection and selection, as well as determined their role in the fight against food shortages among the population of our planet.