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EN
Similar schemes of nuclear transfer technique are applied for farm animal cloning, however, there are some differences between particular species. These differences concern not only procedural aspects, but also the ?genetic age? of cloned animals.
EN
Somatic cell nuclear transfer (SCNT) technique in pigs remains relatively low (2% to 5% of produced piglets), that is why further efforts have to be made to optimize both a multi-step cloning procedure and to improve a structuro-functional quality of recipient oocytes and nuclear donor cells. Pre- and postimplantation developmental potential of porcine SCNT-derived embryos depends to a high degree on not only coordination of mitotic cycle stage with phenotype of nuclear donor cell, but also proper combination of the methods of maternal chromosome elimination (enucleation), oocyte reconstruction techniques, the systems of artificial activation of generated nuclear-cytoplasmic hybrids (clonal cybrids) and in vitro culture of reconstructed embryos. Generally, it can result in increasing the competences of both somatic nuclear and mitochondrial genome for epigenetic remodeling/reprogramming in developing cloned embryos.
EN
The development of non-surgical methods of embryo collection and transfer, primarily in cattle, has led to the commercialization of these techniques, including the production of genetically identical twins. The aim of this paper is to review the progress of the studies on the production of monogenetic progeny using microsurgical bisection of embryos, with a special emphasis put on factors affecting the efficiency of this method. We have also described our new alternative method of monogenetic twin production in cattle based on modified bisection of specifically hatching blastocysts, whose zona pellucida had been perforated.
EN
A stimulus for development of the studies on pig somatic cell cloning, especially in recent years, was above all the possibility of its practical application for production of transgenic piglets using in vitro transfected nuclear donor cells and multiplication of genetically-engineered sows and boars generated so far, on the grounds of important implications for biomedicine, pharmacy and agriculture. However, effective pig somatic cell nuclear transfer, avoiding the sexual reproduction pathway, creates a possibility of providing numerous monogenetic and monosexual offspring derived not only from genetically-transformed individuals, but also from adult (postpubertal) animals of high genetic merit. Generation of cloned transgenic pigs for biomedical purposes to obtain recombinant xenogeneic proteins or organs suitable in xenotransplantology, or to create cell (gene) therapy foundations for a number of serious monogenic diseases that induce heritable (congenital) developmental anomalies, is perceived as a service to humanity.
EN
Domestic goat as a species with a relatively great biodiversity of dairy breeds, which possess high genetic merit and yield of milk production, can be a valuable tool for embryo gene engineering. This involves the generation of transgenic specients, providing with xenogeneic (human) recombinant proteins (i.e. biopharmaceuticals), not only by the standard zygote intrapronuclear microinjection of gene constructs, but above all with the use of somatic cell cloning technology.
EN
Microinjection is one of the most successfully used methods to produce transgenic farm animals. But the effectiveness of transgenesis with the use of microinjection, specially in cattle is still low. Many steps of the transgenesis has been found to influence its effectiveness; DNA purity, the site of its injection, the culture system. There are no reports on the influence of a DNA vector concentration influence on the developmental ability of transformed bovine eggs to the blastocyst stage in the in vitro culture. In presented experiments we investigated the influence of different DNA concentrations on the developmental rate of microinjected immature bovine oocytes, zygotes and 2-cell embryos to the blastocyst stage.
EN
This paper presents the methods of transgenic pigs production and the results based on the long experience of the authors in this area. Moreover, the trends and current issues of transgenic modification in pigs are discussed.
EN
There are many factors affecting transgenic farm animals production. One of them is the effectiveness of the transfer of zygotes and embryos obtained after DNA microinjection. Low effectiveness of the transfer of potentially transgenic blastocysts in cattle is due to their decreased developmental potential in comparison to the blastocysts developed from not microinjected zygotes. A simple short term in vitro culture used for rabbit zygotes after microinjection increased twice the number of produced potentially transgenic rabbits.
EN
Four transgenic pigs, produced with the use of two different gene constructs containing the bovine growth hormone coding gene - Mt-bGH-10D6 (wild type) and Mt-bGH-M8 (mutated), were used to produce the F1 generation to investigate their performance traits. No differences were observed in fattening and slaughter traits between transgenic and non-transgenic pigs. It was found that the weight of ham proper and loin eye area was significantly higher in carriers of Mt-bGH-10D6 gene constructs.
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