Phylogenetic Processes in European and Asian Pig Populations

Abstract

As a result of evolution, a gradual change in the hereditary structure of a species, not only the number of genes changes, but also their properties, frequency, and direction of variability. Changes in gene frequencies occurring over a relatively small period of time belong to microevolution. The breeding process in pig breeding is the microevolutionary processes originating from the ancestral forms of Sus scrofa to the modern specialized breeds of pigs. Genetic monitoring of the genetic systems of blood groups makes it possible to assess the genetic structure and processes occurring in populations. The microevolutionary process of transformation of wild ancestral forms over the last 10-12 thousand years from transitional forms of local aboriginal to factory breeds has occurred with significant genetic and phenotypic transformations in animal populations. In this connection, it is important to clarify the correct understanding of the terms 'population' and 'breed'. Naturally, any breed is a population, but not any population is not a breed, especially since both population and population as taxonomic terms have different interpretations. In the first place, a distinction must be made between wild populations, in which microevolution takes place only by means of natural selection, and breed populations, in the development of which artificial selection was involved as a fundamental factor in microevolution. Depending on the level of methods and forms of selection, we have to distinguish local indigenous populations (e.g., Kakhetian and Mangali breeds) and basic factory breeds (Large White, Berkshire, Landrace, Duroc, etc.), which have been created for decades and centuries. The concept of a breed is closely linked to the size of the reproductive population and the range of distribution. According to FAO, in 2006 there were some 730 breeds and lines of pigs worldwide, most of which are bred in China and Europe, and 270 of which are regarded as rare breeds. At the same time, 58 breeds (25 regional and 33 international) are registered as common, i.e. occurring in more than one country. Five international breeds are now widely distributed: Large White (117 countries), Duroc (93 countries), Landrace (91 countries), Hampshire (54 countries) and Petren (35 countries).