Genetic bases of dog breeding
Genetic basis of breeding dogs. Cross education. Interlinear differences in behavior in ontogenesis show complex genetics. Genes are isolated by conducting cross-education. Litters of newborn puppies belonging to lines with different “linear” behavior change in such a way that the mothers of one line bring up the young of the other. Control animals are raised either by their own mothers or by other females of the same line. When raising litters of aggressive lines by mothers of non-aggressive lines, education did not affect aggression. When raising aggressive lines by mothers of non-aggressive lines, the aggressiveness of the litter increased significantly. However, this change was small compared with interline differences. Thus, the differences between the lines of aggressive behavior are not very inheritable.
First of all, cross-fostering does not eliminate the postnatal influences of the mother. Therefore, only ovarian transplantation, i.e.the separation of the genetic effect from prenatal maternal influences made it possible to establish that in determining the differences in behavior, maternal influence is significant.
Genetic basis of breeding dogs. The effect of the selection of behavioral signs. The selection of behavioral signs in animals are based on the analyzing crosses.
Groups of males and females from a genetically heterogeneous population are determined by a particular behavioral trait. Males with high values of the trait are crossed with the same females, and males with low females are crossed with females, in which this trait is also poorly expressed. The offspring from the resulting cross is tested for the degree of manifestation of the same behavioral trait, and for the next cross the pair is selected according to the same principle. In successive generations, two lines are obtained: one as a result of selection for high indicators of this feature, and the other - for low ones. To control changes in the environment lead another third line - by random crossing. If there is a genetic component in the definition of the trait under study, then the indicators of the “high” and “low” lines in successive generations do notmatch. 11 indicators of the line with random crossing at the same time should not detect systematic deviations
Thus, behavioral signs are regularly formed in ontogenesis. Their development, formation and extinction in the process of individual development is ensured by heredity and habitat. Ontogenetic behavior of dogs is based on a polygenic basis, although there are some examples of monogenic: behavior of males when grooming, diurnal rhythm, responses to stressful irritations, epileptic behavior, behavior with congenital deafness, etc. In any breed of dog there are animals with sharp or gradual, multiple or barely noticeable behaviors. The latter are detected within the life of one or several generations, and when comparing very many. The dynamics of genotypes of behavior may be different in connection with the selection, isolation, mutation process and genetic combinatorics. The selective significance of differences is, of course, determined by heredity. In all cases when thorough studies of genotypes were carried out, their changes, as a rule,they coincided with some kind of environmental change: the cultivation of individuals and the whole offspring, the state of health of parents and children, the size of the litter and the number of genera of bitches, the concentration of odor carriers, the diversity of optical and verbal signals, the vagaries of the weather and the season, feeding and keeping animals. Theoretical calculations and experiments show that at constant "pressure" of the paratype, the increment in the frequency of the allele of the type of behavior over a generation depends on the frequency itself: for a small and high frequency, the change in the alleles of a certain type of behavior is slower than at its mean initial frequencies. Undoubtedly, the persistence of changing conditions for the exploitation of dogs in both large (for dozens of generations) and small scale (for one or two) is enough to explain all the observed diversity in the genetic state of behavior. We add to this the specific features of behavior inherent in each dog (active for brave animals, passive for cowards, etc.), which use dogs in a given mode for a given genotype. These data are well documented by many foreign authors (G. Geiger, K.Rein-terval, R. Riemann, A. Hallgren, S. Mackenzie, K. Mouet, H. Badget, and others) and cynologists of Ukraine (L. Kireeva, O. Kolesnikov, F. Polishchuk, G. Severin, A. Trofimenko and etc.).
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