Somatic cell nuclear transfer (SCNT) Diagram of SCNT Process In somatic cell nuclear transfer ("SCNT"), the nucleus of a somatic cell is taken from a donor and transplanted into a host egg cell, which had its own genetic material removed previously, making it an enucleated egg. After the donor somatic cell genetic material is transferred into the host oocyte with a micropipette, the somatic cell genetic material is fused with the egg using an electric current. Once the two cells have fused, the new cell can be permitted to grow in a surrogate or artificially. This is the process that was used to successfully clone Dolly the sheep (see section on History in this article). The technique, now refined, has indicated that it was possible to replicate cells and reestablish pluripotency-"the potential of an embryonic cell to grow into any one of the numerous different types of mature body cells that make up a complete organism" Induced pluripotent stem cells (iPSCs) Overview of iPS cells Creating induced pluripotent stem cells ("iPSCs") is a long and inefficient process. Pluripotency refers to a stem cell that has the potential to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous tissue). A specific set of genes, often called "reprogramming factors", are introduced into a specific adult cell type. These factors send signals in the mature cell that cause the cell to become a pluripotent stem cell. This process is highly studied and new techniques are being discovered frequently on how to better this induction process. Depending on the method used, reprogramming of adult cells into iPSCs for implantation could have severe limitations in<unk> s. If a virus is used as a reprogramming factor for the cell, cancer-causing genes called oncogenes may be activated. These cells would appear as rapidly dividing cancer cells that do not respond to the body's natural cell signaling process. However, in 2008 scientists discovered a technique that could remove the presence of these oncogenes after pluripotency induction, thereby increasing the potential use of iPSC in<unk> s. Comparing SCNT to reprogramming Both the processes of SCNT and iPSCs have benefits and deficiencies. Historically, reprogramming methods were better studied than SCNT derived embryonic stem cells (ESCs). However, more recent studies have put more emphasis on developing new procedures for SCNT-ESCs. The major advantage of SCNT over iPSCs at this time is the speed with which cells can be produced. iPSCs derivation takes several months while SCNT would take a much shorter time, which could be important for medical applications. New studies are working to improve the process of iPSC in terms of both speed and efficiency with the discovery of new reprogramming factors in oocytes. Another advantage SCNT could have over iPSCs is its potential to treat mitochondrial disease, as it utilizes a donor oocyte. No other advantages are known at this time in using stem cells derived from one method over stem cells derived from the other.
Human cloning
Germ line theory
Biological engineering
Gene delivery
Gene doping
Assisted reproductive technology
Behavioral epigenetics
Genome editing