Editing Genetic transformation (section)

{{Short description|Genetic alteration of a cell by uptake of genetic material from the environment}}
{{distinguish|text=an unrelated process called [[malignant transformation]] which occurs in the progression of [[cancer]]}}
[[File:Bacterial Transformation.svg|thumbnail|In this image, a gene from one bacterial cell is moved to another bacterial cell. This process of the second bacterial cell taking up new genetic material is called transformation.|422x422px]]

In [[molecular biology]] and [[molecular genetics|genetics]], '''transformation''' is the [[Introduction to genetics|genetic]] alteration of a [[cell (biology)|cell]] resulting from the direct uptake and incorporation of [[exogenous DNA|exogenous genetic material]] from its surroundings through the [[cell membrane]](s). For transformation to take place, the recipient bacterium must be in a state of [[Competence (biology)|competence]], which might occur in nature as a time-limited response to environmental conditions such as starvation and cell density, and may also be induced in a laboratory.<ref name=Johnston/>

Transformation is one of three processes that lead to [[horizontal gene transfer]], in which exogenous genetic material passes from one bacterium to another, the other two being [[bacterial conjugation|conjugation]] (transfer of [[plasmid|genetic material]] between two bacterial cells in direct contact) and [[transduction (genetics)|transduction]] (injection of foreign DNA by a [[bacteriophage]] virus into the host bacterium).<ref name=Johnston>{{cite journal | vauthors = Johnston C, Martin B, Fichant G, Polard P, Claverys JP | title = Bacterial transformation: distribution, shared mechanisms and divergent control | journal = Nature Reviews. Microbiology | volume = 12 | issue = 3 | pages = 181–96 | date = March 2014 | pmid = 24509783 | doi = 10.1038/nrmicro3199 | s2cid = 23559881 }}</ref> In transformation, the genetic material passes through the intervening medium, and uptake is completely dependent on the recipient bacterium.<ref name=Johnston/>

As of 2014 about 80 species of bacteria were known to be capable of transformation, about evenly divided between [[Gram-positive bacteria|Gram-positive]] and [[Gram-negative bacteria]]; the number might be an overestimate since several of the reports are supported by single papers.<ref name=Johnston/>

"Transformation" may also be used to describe the insertion of new genetic material into nonbacterial cells, including animal and plant cells; however, because "[[Malignant transformation|transformation]]" has a special meaning in relation to animal cells, indicating progression to a cancerous state, the process is usually called "[[transfection]]".<ref name = "Alberts">{{cite book | title = Molecular Biology of the Cell | first1 = Bruce | last1 = Alberts | first2 = Alexander | last2 = Johnson | first3 = Julian | last3 = Lewis | first4 = Martin | last4 = Raff | first5 = Keith | last5 = Roberts | first6 = Peter | last6 = Walter | name-list-style = vanc | author-link1 = Bruce Alberts | year = 2002 | publisher = Garland Science | location= New York| isbn = 978-0-8153-4072-0 | page= G:35 | url = https://www.ncbi.nlm.nih.gov/books/NBK21052/ }}</ref>