| Cloning |
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Nuclear Transfer-Cloning can reprogram the nucleus of somatic cells to the extreme of bypassing the complex biological processes of gametogenesis and fertilization. Embryos thus reengineered can develop into live offspring. Although remarkable, this process is extremely inefficient. In all species cloned so far, less than 3 % of reconstructed oocytes result in live births. It is remarkable that this technique works at all. The simplistic view is that cloning works only when we can fuse together the perfect nucleus and the perfect egg at the right time. When this occurs (currently fortuitous) the somatic nucleus can rapidly turn off all its somatic-related genes and turn on the ones required for early development. Essentially, a lineage-committed somatic cell is transformed into a totipotent one in a matter of hours. This phenomenon does not naturally occur in nature. We believe that by understanding its basic mechanism, we will be able to generate isogenic totipotent stem cells and increase the efficiency of reproductive cloning. Our animal models for somatic cell nuclear transfer are Bovine and Zebrafish. |