Editing Germline mutation (section)

{{short description|Inherited genetic variation}}
[[File:De novo mutations.png|thumb|292x292px|Transmittance of a [[De novo mutation|''de novo'']] mutation in germ cells to offspring.]]
A '''germline mutation''', or '''germinal mutation''', is any detectable variation within [[germ cell]]s (cells that, when fully developed, become [[sperm]] and [[Egg cell|ova]]).<ref>{{cite web|url=https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=46384|title=NCI Dictionary of Cancer Terms|website=National Cancer Institute|access-date=2017-11-30|date=2011-02-02}}</ref> Mutations in these cells are the only mutations that can be passed on to offspring, when either a mutated [[sperm]] or [[oocyte]] come together to form a [[zygote]].<ref name="Griffiths 2000">{{cite journal|last1=Griffiths|first1=Anthony JF|last2=Miller|first2=Jeffrey H.|last3=Suzuki|first3=David T.|last4=Lewontin|first4=Richard C.|last5=Gelbart|first5=William M. | name-list-style = vanc |date=2000|title=Somatic versus germinal mutation|journal=An Introduction to Genetic Analysis|edition=7th|url=https://www.ncbi.nlm.nih.gov/books/NBK21894/}}</ref> After this fertilization event occurs, germ cells divide rapidly to produce all of the cells in the body, causing this mutation to be present in every [[Somatic (biology)|somatic]] and germline cell in the offspring; this is also known as a constitutional mutation.<ref name="Griffiths 2000"/> Germline mutation is distinct from [[somatic mutation]].

Germline mutations can be caused by a variety of endogenous (internal) and exogenous (external) factors, and can occur throughout zygote development.<ref name=":0">{{cite journal | vauthors = Foulkes WD, Real FX | title = Many mosaic mutations | journal = Current Oncology | volume = 20 | issue = 2 | pages = 85–7 | date = April 2013 | pmid = 23559869 | pmc = 3615857 | doi = 10.3747/co.20.1449 }}</ref> A mutation that arises only in germ cells can result in offspring with a genetic condition that is not present in either parent; this is because the mutation is not present in the rest of the parents' body, only the germline.<ref name=":0" />