Editing Stem cell (section)

===Potency meaning===
{{Main|Cell potency}}
[[Image:Stem cells diagram.png|upright=1.5|thumb|right|Pluripotent, embryonic stem cells originate as inner cell mass (ICM) cells within a blastocyst. These stem cells can become any tissue in the body, excluding a placenta. Only cells from an earlier stage of the embryo, known as the [[morula]], are totipotent, able to become all tissues in the body and the extraembryonic placenta.]]
[[Image:Human embryonic stem cells.png|thumb|Human [[embryo]]nic stem cells <br /> A: Stem cell colonies that are not yet differentiated. <br /> B: [[Nerve]] cells, an example of a [[cell type]] after differentiation.]]

[[Cell potency|Potency]] specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.<ref name=Schoeler>{{cite book |title=Humanbiotechnology as Social Challenge |editor1=Nikolaus Knoepffler |editor2=Dagmar Schipanski |editor3=Stefan Lorenz Sorgner |page=28 |chapter=The Potential of Stem Cells: An Inventory | last = Schöler | first = Hans R. | name-list-style = vanc |publisher=Ashgate Publishing|year=2007 |isbn=978-0-7546-5755-2}}</ref>
* [[Totipotency|Totipotent]] (also known as omnipotent) stem cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable organism.<ref name=Schoeler/> These cells are produced from the [[Cell fusion|fusion]] of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent.<ref>{{cite book | vauthors = Mitalipov S, Wolf D | chapter = Totipotency, pluripotency and nuclear reprogramming | volume = 114 | pages = 185–199 | year = 2009 | pmid = 19343304 | pmc = 2752493 | doi = 10.1007/10_2008_45 | isbn = 978-3-540-88805-5 | series = Advances in Biochemical Engineering/Biotechnology | bibcode = 2009esc..book..185M | title = Engineering of Stem Cells | publisher = Springer }}</ref>
* [[Pluripotency|Pluripotent]] stem cells are the descendants of totipotent cells and can differentiate into nearly all cells,<ref name=Schoeler/> i.e. cells derived from any of the three [[germ layer]]s.<ref>{{cite journal | vauthors = Ulloa-Montoya F, Verfaillie CM, Hu WS | title = Culture systems for pluripotent stem cells | journal = Journal of Bioscience and Bioengineering | volume = 100 | issue = 1 | pages = 12–27 | date = July 2005 | pmid = 16233846 | doi = 10.1263/jbb.100.12 | url = https://lirias.kuleuven.be/handle/123456789/238336 }}</ref>
* [[Multipotency|Multipotent]] stem cells can differentiate into a number of cell types, but only those of a closely related family of cells.<ref name=Schoeler/>
* [[Oligopotency|Oligopotent]] stem cells can differentiate into only a few cell types, such as lymphoid or myeloid stem cells.<ref name=Schoeler/>
* [[Unipotency|Unipotent]] cells can produce only one cell type, their own,<ref name=Schoeler/> but have the property of self-renewal, which distinguishes them from non-stem cells