The selection of animals appeared about 30 thousand years agoBC simultaneously with the development of the process of domestication of representatives of wild fauna. Initially, people used the method of the so-called unconscious selection, choosing those individuals who were better suited to the person could be useful, more flexible, obedient and, most importantly, able to continue their race in captivity, multiply.
Approximately 9 thousand years before Christ, man becamemore carefully select certain useful qualities in animals, that is, the era of methodical selection began. It was then that the selection of plants and animals began to develop in a way more familiar to us. But domestication, as well as the method of selection, remains so far. For example, it is worth noting such a branch as fur farming.
Peculiarities of animal breeding
It is necessary to highlight the features of animal selection according tocompared with plant breeding. First, representatives of the fauna are able to reproduce only sexually, that is, a large proportion of the population have heterozygous organisms. Secondly, they have a longer period of maturity. Mammals are capable of reproduction not immediately after birth, but several years later. The third feature is that the representatives of fauna of the offspring are much less than in plants.
All these features have formed special methodsbreeding, not inherent to representatives of the flora. Of course, the basic methods, which include hybridization and selection, have been preserved. But there were also completely different methods not applicable to plants.
Methods of selection
Near-crossing, or imbriding,is due to the pairing of individuals who come to each other by sisters and brothers or descendants and parents. As a result, the necessary sign can go to a homozygous state. However, it should be noted that over time there is a loss or significant deterioration in the viability of the obtained individuals.
Interbreeding, or outbreeding,It is necessary to fix the qualities necessary for a person, which are available for both breeds. Due to outbreeding, a huge variety of valuable breeds were obtained, for example, a white steppe Ukrainian pig, obtained from the crossing of a white English boar with outbred Ukrainian pigs. As a result, the selection of animals made it possible to obtain a rock with a larger mass, a high content of fat, meat, and extremely unpretentious.
Remote hybridization implies crossingpairs that belong to different types. This method has a huge minus: all the offspring are barren. But even this problem the selection of animals was able to overcome. A vivid example of remote hybridization is the mule, which is a cross between a donkey and a mare. The mule is distinguished by the great endurance of the donkey and the complaisant nature of the horse.
Another method is artificial insemination. It is used to get as many as possible offspring from a particular manufacturer.
Another new and very interesting method -transplantation of embryos. It is based on a rather complex medical operation, when the necessary female by hormonal therapy increases the number of eggs. Then the eggs are fertilized, embryos are removed, which are attached to other animals that perform the role of a surrogate mother, or frozen at a temperature of 273 ° C. Then they can be stored for a long period of time in order to be able to use in the future.
Thus, the selection of animals solves one of thethe most important problems of all mankind - the problem of finding food and food. Modern science allows us to create new species, which to a greater extent satisfy the needs of people. And science never stands still.
