The article considers methods used for breeding and selection of mini-pigs in the ICG, SB RAS, the theoretical justifcation of these methods and the purposes for which they are used. We showed the genealogical structure of the herd and the contribution of inbreeding to the genetic similarity of modern representatives of genealogical lines and families with the founders of the breeding group. We characterized the phenotypic diversity of the ICG mini-pigs in colours, weight categories, types of growth and features of constitution. We listed measures supporting genetic diversity in the herd of the ICG mini-pigs. We explained the possibility of using similarity indices calculated by using portions of the ancestors’ blood (genome) for the selection of parental pairs and the evaluation of genetic consolidation of the herd. We showed that the average index of similarity between males and females, calculated by using portions of the ancestors’ blood, in the ICG minipigs is close to the limit value. It turned out that effective evaluation of the genetic potential of mini-pigs in growth rate and fnal size of individuals is only possible under the condition of a rich and full feeding of young animals. The time scale of estimation of growth of live weight of the ICG mini-pigs for three weight categories allocated in the selection group is presented. The types of growth and development of mini-pigs observed in the ICG breeding group and the type inherent to individuals in the small weight category are considered. We justifed the minimum live weight of a newborn piglet in the herd of the ICG mini-pigs. Values of optimal multiple pregnancy for the three categories of ICG mini-pig sows were calculated.
Modern studies on porcine endogenous retroviruses are considered in the review. Data on the nucleotide sequences of retroviruses, their expression, and the isolation of mature virions is discussed. The tropism of endogenous retroviruses to human cells and retrospective studies of patients are considered in detail. A critical overview of works on in vitro and in vivo interspecific transmission of porcine endogenous retroviruses is presented. Tactics for preventing possible infection and treating humans for it are discussed. Based on the overviewed data, it is concluded that the risk of infection transmission from xenograft recipients to the rest of the population is very low. This low risk can be further reduced by careful observation and, prob ably, vaccination of contacting persons, as well as by preventive use of antiviral drugs. The minor risk of infec tion transmission can also be reduced by application of modern biotechnological methods to raise pigs that have no endogenous viruses tropic to humans.
Analysis of the frequencies of chromosomes carrying various classes of porcine endogenous retroviruses (PERVs) and combinations of these classes was performed in the swine species Sus scrofa L. by using maps constructed in two principal component coordinates. Four population clusters can be recognized in the maps. Cluster 1 is formed by wild boars,cluster 2 by domestic meat breeds, cluster 3 by meat-and-lard (universal) breeds, and cluster 4 by miniature pigs. The maps indicate that modern domesticated swine meat breeds are the closest to the wild type. Meat-and-lard domestic swine breeds are more distant from wild boars, and miniature pigs are diverged the most. The maps showed that microevolution processes associated with PERV carriership frequency had two basic dimensions, or vectors: the vector of fat deposition variation and the “minus” selection vector (determination of commercial traits). Thus, PERVs may cause variation in pig physiology
The genes encoding esterase D (ESD) and α2-macroglobulin (A2M) were mapped using 3H-labeled cDNAs to sheep chromosome 3p26→p24 and 3q26→q35 respectively.
Technology for preparation of chymosin from milk of transgenic sheep has been elaborated. Purification of the preparation by ion-exchange chromatography on aminosilochrom and biospecific chromatography on bacitracin-Sepharose yielded homogeneous active enzyme. Hydrolysis of protein substrates (hemoglobin, BSA, and sodium caseinate) by the transgenic sheep chymosin and stability of the enzyme at various values of pH were studied. Judging by the amino acid composition, the N-terminal sequence involving six amino acid residues, molecular mass, stability at various pH values, and the catalytic activity against the protein substrates, the transgenic sheep chymosin is identical to calf chymosin.
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