УДК 636.2:576.315.086.862:591.39 OPTIMIZATION OF PARAMETERS OF THE OOCYTE ENUCLEATION AND FUSION WITH THE SOMATIC CELL DURING PRODUCTION OF MAMMALIAN CLONED EMBRYOS 1 All-Russia Research and Development Institute for Livestock Husbandry, RAAS, Dubrovitsy settlement 142132, Moscow province, Russia e-mail: g_singina@mail.ru, vubi_myaso@mail.ru, n_zinovieva@mail.ru G.N. Singina1, A.V. Lopukhov1, N.A. Zinovieva1, E.V. Shapkanova2, A.A. Puzik3 3 Smolensk Research and Development Institute of Agriculture, RAAS, Smolensk 214025, Russia e-mail: smniish@yandex.ru 2 Velikiye Luki State Agricultural Academy, Velikie Luky 182100, Pskov province, Russia e-mail: lenok150185@mail.ru Received January 15, 2013 S umma r y Parameters of the oocyte enucleation and fusion with somatic cell for producing of cattle cloned cetohybrids were studied. <...> It was established that the electrofusion efficiency depends on strength, duration and set number of electrical pulse. <...> The optimal parameters for Multiporator (Eppendorf, Germany) were determined: two consistent pulses DC electrical field each of 30 V field strength and 15 msec duration followed by the pulse of AC electrical field of 5 V and 10 sec duration. <...> It was found that the first polar body serving as a marker for the chromosome position at «blind» enucleation must not deviate from the chromosome location by more than 10 degrees. <...> Somatic cloning is widely used in biomedical research and in production of transgenic animals (1). <...> To create a clone, genetic material of the host’s egg cell is replaced by genetic material of a somatic cell (reprogramming). <...> It is often associated with complete removal of the oocyte’s chromosomes at metaphase II, after which the somatic donor cell is introduced in the perivitelline space of the (5). <...> The procedure is visualized by staining of the chromosomes with fluorescent vital dye Hoechst 33342 allowing enucleation of the host oocyte under ultraviolet light (6). <...> However, this approach adversely affects viability of cells and future embryos (7). <...> The alternative solution is blind enucleation when metaphase chromosomes are recognized by location of the first polar body that serves as a reference point. <...> This method is considered as more safe for viability of the egg cells and their capacity <...>