Clones are lost from the earliest developmental stages and throughout pregnancy . now more and more studies support the evidence on the failure of cloning : chromatin inappropriate epigenetic reprogramming , and then result in abnormal genes expression 大量的研究表明，克隆动物在核移植后其染色质的再程序化表现异常，使细胞不能成功地通过调节转录活性而有效地控制其发育分化。
Traditionally , somatic nuclear transfer in mammal is completed by micromanipulation . but micromanipulation is evidently damaging to cytoplast cytoskelton , causing the lost of some important factors involved in programming of donor karyoplast , reducing the volume of cytoplasm 传统核移植总效率低，且需要熟练的显微操作技术，所需设备昂贵，限制了核移植的广泛应用；因此作为替代，化学去核应运而生。
The results indicate that maturation rate of buffalo oocytes increase as the ivm duration prolongs , while the enucleation rate decreases , however , which has no significant difference on development of nt embryos with different enucleation time of oocytes during ivm16 ~ 24h 结果表明，水牛卵母细胞的成熟率随着成熟时间的延长不断提高，而去核率呈下降趋势，但对其随后的核移植效果没有显著影响(在ivm16 24h期间) 。
On november 14th nature , one of the world ' s leading scientific journals , published a paper about the creation of embryonic stem cells using a technique called somatic - cell nuclear transfer ( basically , taking the nucleus from a body cell and putting it in an unfertilised egg ) 世界前沿科学期刊《自然》于其11月14日的杂志上刊登了一篇关于如何通过体细胞核移植制造胚胎干细胞的论文（简单的说，体细胞核移植就是从体细胞提取细胞核后放入未受精卵中的过程） 。
This simple two - step chemical enucleation procedure yields fully enucleated mouse oocytes in 85 . 6 % of cumulus - oocytes complexes and 56 % of natural oocytes , significantly different ( p < 0 . 05 ) . since the enucleation rate of cumulus - oodles complexes is equivalent to that by micromanipulation , induced enucleation will greatly improve the whole efficiency in mouse somatic nulear transfer 该方法完全丢弃了传统核移植的显微操作及其繁琐程序，是纯粹的手工克隆( hmc ) ，它的成功将会大大简化核移植程序，提高核移植效率，加快其产业化的步伐。
This study were designed to investigate development potency of the reconstructed embryos of black bear - cat inter - species nuclear transfer in vitro / vivo , to develop the principle and technology of somatic nuclear transplantation in inter - species of mammalian and to study the mechanism of coordination between cell nuclear and cytoplasm . somatic nuclear transplantation technology has been used to establish stem cell from different animals , which can provide materials to treat various diseases 本研究运用体细胞核移植的原理和技术，以六月龄雌性黑熊的成纤维细胞为供核体，去核未受精家猫成熟卵母细胞为受体，构建种间核移植重组胚胎，研究种问体细胞核移植胚胎的构建方法和重组胚胎的体内外发育潜能及其影响因素。
Different from mammals , the early embryos of fish can not be preserved for the long period at the very low temperature ( - 196 ) . therefore , three methods were usually applied to cryogenic preservation of the fine and rare species of fish : 1 ) perserving fish spermatozoon in cryogenic condition . researchers have had systematically studied on this technique for many years , and this technique has been utilized in application and made a lot of effects ; 2 ) combining with the techniques of cell engineering ( nuclear transplantation and electric fusion etc . ) , and through the process of culturing histiocyte of fish , cryopreservation and re - culture after thawing , carrying out somatic cell breeding of fish . the past studies showed that the nucleolus of somatic cells of fish have totipotency 多年来，国内外学者对各种鱼类精液的冷冻保存进行了大量的系统研究，目前这项技术已达到实用水平，并日益发挥作用；二是对鱼类培养的组织细胞冷冻保存，通过鱼类细胞的培养、超低温冻存、解冻后再培养过程，结合细胞工程技术(如核移植、电融合等)进行体细胞育种；大量的研究结果表明鱼类体细胞核具有发育的全能性，随着细胞培养技术、细胞工程技术日益发展成熟，完全具备实现鱼类物种种质长期保存的理论基础和技术条件。
This study were designed to investigate development potency of the reconstructed embryos of rat - mouse and rat - bovine inter - species nuclear transfer in vitro / vivo , to develop the principle and technology of somatic nuclear transplantation in inter - species of mammalian and to study the mechanism of coordination between cell nuclear and cytoplasm . somatic nuclear transplantation technology has been used to establish stem cell from different animals , which can provide material to treat various diseases 本研究运用体细胞核移植的原理和技术，以成年大鼠的成纤维细胞为供体，去核小鼠和牛成熟卵母细胞为受体，构建种间核移植重组胚胎，研究种间体细胞核移植胚胎的构建方法和重组胚胎的体内外发育潜能及其影响因素。
By nuclear transferee transfered the nih 3t3 cell to enucleated gv and mii oocyte . the immunofluorescence results showed that jak . 2 was not transfered to somatoblast nuclear whether the recombined oocyte occured gvbd or not . when transfered somatoblast nuclear to enucleated and integrated m ii oocyte , the immunofluorescence results showed that jak2 only existed in the nuclear of integrated m ii oocyte but not the somatoblast nuclear . the nuclear transfer implied that the mature and immature oocyte cytoplasm could not transfer the jak . 2 protein to donor nuclear 通过核移植，将nih3t3体细胞核移入去核gv期和m期的卵母细胞中。荧光检测发现，体细胞核与去核gv期卵母细胞质构成的重组卵无论是否发生gvbd ，核内均没有jak2的出现。在去核和未去核的m期卵母细胞中移入体细胞核， jak2仅存在于未去核m期卵母细胞的核内，并不转移到体细胞核内。
These observations show that reprogramming is easier in interspecific embryos reconstructed with es cells than that reconstructed with somatic cells , and that es cells have the higher ability to direct the reconstructed embryo development normally than fibroblast cells . oocytes were reconstructed with outbreeding kunming albino mouse es cells and enucleated rabbit oocytes , and the effects of the passages of es cells and 6 - dmap on the development of interspecific reconstructed oocytes were analyzed . the interspecific reconstructed es - rabbit oocytes were activated either by combined two set electric pulses and 6 - dmap or by two set electric pulses 以上结果显示， 6 dmap能增加胚胎干细胞异种重构卵的卵裂率，对重构卵囊胚的发育率影响不大；高培养代数和低培养代数的胚胎干细胞用于异种核移植不影响异种重构卵的卵裂率和囊胚发育率；用胚胎干细胞作为供核细胞；比体细胞作为供核细胞所构建的异种重构胚更容易进行重编程，并且胚胎于细胞指导异种克隆胚胎正常发育的能力强于体细胞。
