Problems of mini-pig breeding

This article provides an overview of some problems of the breeding and reproduction of laboratory minipigs. The most obvious of these are the lack of centralized accounting of breeding groups, uniform selection standards for reproduction and evaluation of breeding animals, as well as minimizing the accumulation of fitness-reducing mutations and maintaining genetic diversity. According to the latest estimates, there are at least 30 breeding groups of mini-pigs systematically used as laboratory animals in the world. Among them, there are both breed formations represented by several colonies, and breeding groups consisting of a single herd. It was shown that the main selection strategy is selection for the live weight of adults of 50–80 kg and the adaptation of animals to a specific type of biomedical experiments. For its implementation in the breeding of foreign mini-pigs, selection by live weight is practiced at 140- and 154-day-old age. It was indicated that different herds of mini-pigs have their own breeding methods to counteract inbred depression and maintain genetic diversity. Examples are the maximization of coat color phenotypes, the cyclical system of matching parent pairs, and the structuring of herds into subpopulations. In addition, in the breeding of foreign mini-pigs, molecular genetic methods are used to monitor heterozygosity. Every effort is made to keep the number of inbred crosses in the breeding of laboratory mini-pigs to a minimum, which is not always possible due to their small number. It is estimated that to avoid close inbreeding, the number of breeding groups should be at least 28 individuals, including boars of at least 4 genealogical lines and at least 4 families of sows. The accumulation of genetic cargo in herds of mini-pigs takes place, but the harmful effect is rather the result of erroneous decisions of breeders. Despite the fact that when breeding a number of mini-pigs, the goal was to complete the herds with exclusively white animals, in most breeding groups there is a polymorphism in the phenotype of the coat color

Breeding and selection of mini-pigs in the ICG SB RAS

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

Multidirectional sexual dimorphism for the live weight in domestic pigs

In mammals, males are typically larger and heavier than females. In particular, the average weight of wild boar females is about 80% of that of the males. In a vast majority of domestic swine populations (breeds, populations of breeding groups), this value varies from 70 to 91% (the central value of the range of variation of 81%). However, there are three genealogically continuous groups of domestic pigs (Vietnamese Masked breed MY, minisibs and Svetlogorsk mini-pigs) that make exceptions. Their specific feature is the reverse sexual dimorphism in weight – mature females are heavier than males. This phenomenon, not typical of the species Sus scrofa, was the reason for the present study. Although this research is preliminary, some assumptions can be made. Firstly, the ratio of the weight of mature females to the weight of mature males is obviously characteristic of the species, deviations from which repressed stabilizing selection. Second, in domestic pigs, normal and reverse sexual dimorphism in weight may be different in nature: in the former case, it is a great length of the period of intensive growth in males, in the latter, a large growth rate of females during the first year of life. The third characteristic of domestic pigs in Southeast Asia, early puberty, may be due to a consistent use of young and therefore small-sized males for reproduction purposes; however, the small size due to their youth, cannot be a target of artificial selection – nor can they be the cause of reverse sexual dimorphism in weight. Finally, reverse sexual dimorphism may be due to a tendency towards early obesity in females, which might be to a single mutation as its genetic cause

Proposal for a procedure for measuring the transverse dimensions of a beam of relativistic electrons with a small longitudinal size

The possibility of implementing a previously proposed procedure for determining the beam dimensions at a target is analyzed; it includes the measurement of two-dimensional angular distributions of the coherent radiation of fast electrons for two distances between a crystal, where radiation is generated, and a coordinate detector. The use of two mechanisms of parametric X-ray radiation and diffracted transition radiation is considered. The limits of the method sensitivity and the influence of the departure of secondary electrons and photons on them are discusse

Association of haplotypes for SNPs in the LTR regions of bovine leukemia virus with hematological indices of cattle

Molecular typing of BLV samples isolated from Holsteinized Russian Black Pied cattle was carried out, and various cytofluorometric and morphological blood indices were examined. We performed the total count of white blood cells (WBC), lymphocyte (lymf), granulocyte (gran), monocyte (mon), red blood cell (RBC), hemoglobin (HGB), hematocrit (HTC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet crit count (PCT). The LTR-region of BLV was haplotyped. Only viruses of haplotypes I (0.33±0.03) and III (0.67±0.03) of the eight possible were detected. The ratio of hematologically sick, healthy, and suspected carriers of BLV of haplotypes I and II was comparable with the results of other researchers. The numbers of leukocytes, erythrocytes and platelets in the blood of carriers of haplotype III exceeded the corresponding parameters of cattle affected by the virus of haplotype I. It is interesting to note that the difference in the hemolytic status of animals was manifested not only by the concentration of leukocytes as direct immune agents but also by the count of erythrocytes and platelets, which are not directly involved in the immune response. The number of particles of haplotype III of the BLV circulating in the blood of infected individuals exceeded that of the carriers of haplotype I. In this connection, an assumption was made about the evolutionary advantage of the more virulent haplotype III. However, the results of our own research in conjunction with the data of other scientists indicate that the high virulence of individual virus strains is a consequence of the tendency to implement the maximum possible intensity of the synthesis of virus particles but not of the high damaging effect alone. It is shown that high lethality is evolutionarily disadvantageous for viruses, since the extinction of the carrier as a biological species is fraught with the disappearance of the virus itself

Juvenile coat colours in mini-pigs at ICG

This article continues a previous study colors in minipigs at ICG. It also has a phenomenological character, but it consideres juvenile colour, which is an integral element of the ontogenetic formation of the suit, wild type agouti pigs of the species Sus scrofa L. However, in ICG mini pigs, in addition to individuals with the suit of the wild type, juvenile colour is a feature of pigs with the black spotted suit. It should be noted that data about a similar phenomenon in pigs with black spotted colour were not found in the literature. We proposed that a unique juvenile colour of black spotted mini-pigs ICG is a consequence of increased synthesis of pigments of hair, the intensity of which obviously exceeds the performance by the wild boar and domestic pigs. Newborn piglets of mini pigs ICG of the colour of the wild type typically have too little or too much yellow (orange, brown) pigment, which makes the figure of juvenile livery blurry – low contrast, or the lack of it, with the result that they are gray or gray-blue color with dark gray longitudinal stripes. The pattern of juvenile livery piglets of mini pigs ICG is disrupted. As a rule, instead of a longitudinal stripe, a mesh pattern livery is observed. Therefore, the agouti like colour observed in mini-pigs ICG should rather be called more properly pseudowild type. It was suggested that the specially planned crosses were able to “reveal” the genetic load of mutations in the complex of alleles involved in the formation of the suit of the wild type and accumulated in the population, not exposed to stabilizing selection on this archaic for domestic pigs’ colour. The accumulation of this genetic cargo at the mini-pigs was made possible by gipostatic suit wild type relative to epistatic colour standard for modern commercial plant breeds

Polymorphic loci of coat color in mini-pigs

The present work is phenomenological and purely descriptive. It shows polymorphism of colors in a breeding group of mini-pig in the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences (ICG SB RAS) and makes some assumptions about the nature of this genetic diversity. In the ICG SB RAS mini-pig herd, wild-type coloration (agouti), black-spots, black and white color are present. All these options have variants, including previously undescribed, with genetically determined differences. In addition, the ICG SB RAS mini-pigs have variants inherent only to heterozygous individuals and archaic gray color described only in primitive domestic pig. Comparison of the observed color phenotypes in the breeding with literature data showed that EDNRB, KIT, KITLG and the MC1R are polymorphic loci, while ASIP, OCA2 and TYRP1 are monomorphic loci. Thus, the loci that control the most common coat colors in domestic pigs are polymorphic, while those controlling rare or relatively rare colors and monomorphic. The research allowed us to put forward some assumptions concerning the genetic determination of the phenotypic characteristics of color seen in the study group selection. Among these assumptions is one about the genetic control of juvenile colors in domestic pigs. Observations made in the ICG SB RAS mini-pig breeding group allowed us to examine and describe the features of age-related changes of an embodiment of black-motley suit, when newborn piglets originally have black-and-motley fur color on the brick-red background and at an age of one year, a gray roan background formed by a mixture of white and black hairs. In addition, it was shown that with the help of technical means black spots can also be detected on a black background

Frequency-resolved Monte Carlo

We adapt the Quantum Monte Carlo method to the cascaded formalism of quantum optics, allowing us to simulate the emission of photons of known energy. Statistical processing of the photon clicks thus collected agrees with the theory of frequency-resolved photon correlations, extending the range of applications based on correlations of photons of prescribed energy, in particular those of a photon-counting character. We apply the technique to autocorrelations of photon streams from a two-level system under coherent and incoherent pumping, including the Mollow triplet regime where we demonstrate the direct manifestation of leapfrog processes in producing an increased rate of two-photon emission events

ВЛИЯНИЕ ИНТРОДУКЦИИ АЛЛЕЛЕЙ НА СОСТОЯНИЕ АЛЛЕЛОФОНДА ЛОКУСОВ СИСТЕМ ГРУПП КРОВИ В ПОПУЛЯЦИИ МИНИАТЮРНЫХ СВИНЕЙ ИЦиГ СО РАН

The paper shows the part played by the introduction of blood group systems alleles as the factor of formation of allele pool of immune genetic markers in SB RAS ICG diminutive pig population. (further DMP) The DMP blood added to the blood of Landrace (1998) and Vietnamese boars (2005, 2010) made the DMP herd have the alleles, such as Eedf, Ladhjl and Lagim. It was the introduction of the alleles from Landrace and Vietnamese boars rather than convergation processes that made the crucial contribution to the phylogenetic mapping of the modern DMP population, that being well-reasoned and testified to. Based on the allele presence/absence, two major components were spaciously plotted in the map through Euclidean distances. The components show DMP clusterized with the pig breeds and populations which were used in their production. Given the grouping happened based on the 2013 data about the presence or absence of blood group systems alleles, the modern DMPs are found in the same cluster with Svetlogorsky mini-boars, minisibs and Vietnamese breed. Given the clusterization resting upon the alleles detected in the population founders, DMPs are found in the same cluster with Svetlogorsky founding boars. In addition, the paper shows the contribution of each of the initial forms to the gene pool of the modern DMP population as well as the contribution of each of its founders. Over a half of the blood portion belongs to the Svetlogorsky founding boars, but the contribution of each of the rest of the predecessors constitutes nearly 0.1–0.2.Показана роль интродукции аллелей систем групп крови как фактора формирования ал- лелофонда иммуногенетических маркёров популяции миниатюрных свиней ИЦиГ СО РАН (далее МС). «Прилитие крови» хряков пород ландрас (1998 г.) и вьетнамская (2005, 2010 гг.) привело к появлению в генофонде МС таких аллелей, как Eedf, Ladhjl и Lagim. Приведены аргументированные доказательства того, что решающий вклад в построение филогенетической карты современной популяции МС оказала интродукция аллелей от хряков пород ландрас и вьетнамская, а отнюдь не конвергенционные процессы. На основании наличия/отсутствия маркерных аллелей при помощи евклидовых дистанций построены карты в пространстве двух главных компонент, показывающие кластеризацию МС с породами и популяциями свиней, которые использовались при их выведении. В том случае, когда группировка производилась на основании данных 2013 г. о наличии либо отсутствии аллелей систем групп крови, современные МС находятся в одном кластере со светлогорскими мини-свиньями, минисибсами и вьетнамской породой. В случае же кластеризации на основании аллелей, обнаруженных у основателей популяции, МС находятся в одном кластере со светлогорскими хряками-родоначальниками. Кроме того, показан вклад каждой из исходных форм в генофонд современной популяции МС, а также вклад каждого из её основателей. Более половины «доли крови» приходится на светлогорских хряков-родоначальников, а вклад каждой из остальных предковых форм составляет около 0,1–0,2

Unusual congenital polydactyly in mini-pigs from the breeding group of the Institute of Cytology and Genetics (Novosibirsk, Russia)

The article describes a new phenomenon in the breeding group of mini-pigs at the Institute of Cytology and Genetics (ICG, Novosibirsk): polydactyly (extra digits), which is unusual because the additional digits are situated at the lateral surface of legs or at the lateral and medial ones. This anomaly was first found here in 2017 in adult animals intended for culling due to incorrect positioning of the legs caused by flexor tendon laxity and resulting in weight-bearing on the palmar surface of the proximal phalanges (“bear’s paw”). Therefore, the polydactyly of mini-pigs has a pronounced negative selection effect. A visual survey of the livestock was conducted, and a description of the detected anomaly was compiled. The polydactyly in mini-pigs is a stand-alone trait and is not part of any syndromes. Individuals with polydactyly may have extra digits either on pectoral or on pectoral and pelvic limbs. On thoracic limbs, there may be either one lateral digit or a lateral digit and a medially located rudimentary hooflet. On pelvic limbs, only lateral extra digits can occur. Anatomical and morphological analyses showed that the lateral extra digit is an anatomically complete (“mature”) structure, whereas the medial rudimentary digit consists of only a hooflet without other structures characteristic of normal digits. Cytological examination revealed no specific karyotypic features, except for Robertsonian translocation Rb 16;17 previously reported for the mini-pigs of the same livestock. Cytological findings indicated that the polydactyly and Robertsonian translocation are not linked genetically. Genealogical analysis and results of crosses are consistent with a working hypothesis of recessive inheritance of the trait. Overall, the study shows that this type of polydactyly is anatomically and morphologically unique and not typical of Sus scrofa. In this species, only polydactyly types with medial accessory toes have been described and are usually inherited as a dominant trait with incomplete penetrance. In our case, the results of test crosses indicate recessive inheritance of the trait with varying expression and incomplete penetrance, because of which poorly expressed phenotypes are not visually detectable