Editing X-inactivation (section)

===== Timing =====

The timing of each process depends on the species, and in many cases the precise time is actively debated. [The whole part of the human timing of X-inactivation in this table is highly questionable and should be removed until properly substantiated by empirical data]
{| class="wikitable"
|+Approximate timing of major events in the X chromosome activation cycle
|
|'''Process'''
|'''Mouse'''
|'''Human'''
|-
|1
|Zygotic genome activation
|2–4 cell stage<ref name=":4">{{cite journal | vauthors = Xue Z, Huang K, Cai C, Cai L, Jiang CY, Feng Y, Liu Z, Zeng Q, Cheng L, Sun YE, Liu JY, Horvath S, Fan G | title = Genetic programs in human and mouse early embryos revealed by single-cell RNA sequencing | language = En | journal = Nature | volume = 500 | issue = 7464 | pages = 593–7 | date = August 2013 | pmid = 23892778 | pmc = 4950944 | doi = 10.1038/nature12364 | bibcode = 2013Natur.500..593X }}</ref>
|2–8 cell stage<ref name=":4" />
|-
|2
|Imprinted (paternal) X-inactivation
|4–8 cell stage<ref name=":2" /><ref name=":3">{{cite journal|vauthors=Borensztein M, Syx L, Ancelin K, Diabangouaya P, Picard C, Liu T, Liang JB, Vassilev I, Galupa R, Servant N, Barillot E, Surani A, Chen CJ, Heard E|date=March 2017|title=Xist-dependent imprinted X inactivation and the early developmental consequences of its failure|journal=Nature Structural & Molecular Biology|language=En|volume=24|issue=3|pages=226–233|doi=10.1038/nsmb.3365|pmc=5337400|pmid=28134930}}</ref>
|Unclear if it takes place in humans<ref name=":5">{{cite journal | vauthors = Deng X, Berletch JB, Nguyen DK, Disteche CM | title = X chromosome regulation: diverse patterns in development, tissues and disease | language = En | journal = Nature Reviews. Genetics | volume = 15 | issue = 6 | pages = 367–78 | date = June 2014 | pmid = 24733023 | pmc = 4117651 | doi = 10.1038/nrg3687 }}</ref>
|-
|3
|X-activation
|Early blastocyst stage
|Early blastocyst stage
|-
|4
|Random X-inactivation in the embryonic lineage (inner cell mass)
|Late blastocyst stage
|Late blastocyst stage, after implantation<ref name=":5" />
|-
|5
|X-reactivation in primordial germ cells before meiosis
|
|From before developmental week 4 up to week 14<ref>{{cite journal | vauthors = Vértesy Á, Arindrarto W, Roost MS, Reinius B, Torrens-Juaneda V, Bialecka M, Moustakas I, Ariyurek Y, Kuijk E, Mei H, Sandberg R, van Oudenaarden A, Chuva de Sousa Lopes SM | display-authors = 6 | title = Parental haplotype-specific single-cell transcriptomics reveal incomplete epigenetic reprogramming in human female germ cells | language = En | journal = Nature Communications | volume = 9 | issue = 1 | pages = 1873 | date = May 2018 | pmid = 29760424 | pmc = 5951918 | doi = 10.1038/s41467-018-04215-7 | bibcode = 2018NatCo...9.1873V }}</ref><ref>{{cite journal | vauthors = Guo F, Yan L, Guo H, Li L, Hu B, Zhao Y, Yong J, Hu Y, Wang X, Wei Y, Wang W, Li R, Yan J, Zhi X, Zhang Y, Jin H, Zhang W, Hou Y, Zhu P, Li J, Zhang L, Liu S, Ren Y, Zhu X, Wen L, Gao YQ, Tang F, Qiao J | display-authors = 6 | title = The Transcriptome and DNA Methylome Landscapes of Human Primordial Germ Cells | journal = Cell | volume = 161 | issue = 6 | pages = 1437–52 | date = June 2015 | pmid = 26046443 | doi = 10.1016/j.cell.2015.05.015 | doi-access = free }}</ref>
|}