Editing Caenorhabditis elegans (section)

==== Axis formation ====
The resulting daughter cells of the first cell division are called the AB cell (containing PAR-6 and PAR-3) and the P1 cell (containing PAR-1 and PAR-2). A second cell division produces the ABp and ABa cells from the AB cell, and the EMS and P2 cells from the P1 cell. This division establishes the dorsal-ventral axis, with the ABp cell forming the dorsal side and the EMS cell marking the ventral side.<ref>{{cite book | title=Developmental biology| edition=11th| author=Gilbert SF| year=2016| pages=272| publisher=Sinauer| isbn=9781605354705}}</ref> Through [[Wnt signaling pathway|Wnt signaling]], the P2 cell instructs the EMS cell to divide along the anterior-posterior axis.<ref name="pmid9288749">{{cite journal | vauthors = Thorpe CJ, Schlesinger A, Carter JC, Bowerman B | title = Wnt signaling polarizes an early ''C. elegans'' blastomere to distinguish endoderm from mesoderm | journal = Cell | volume = 90 | issue = 4 | pages = 695–705 | date = August 1997 | pmid = 9288749 | doi = 10.1016/s0092-8674(00)80530-9 | doi-access = free }}</ref> Through [[Notch signaling pathway|Notch signaling]], the P2 cell differentially specifies the ABp and ABa cells, which further defines the dorsal-ventral axis. The left-right axis also becomes apparent early in embryogenesis, although it is unclear exactly when specifically the axis is determined. However, most theories of the L-R axis development involve some kind of differences in cells derived from the AB cell.<ref>{{cite journal | vauthors = Pohl C, Bao Z | title = Chiral forces organize left-right patterning in ''C. elegans'' by uncoupling midline and anteroposterior axis | journal = Developmental Cell | volume = 19 | issue = 3 | pages = 402–12 | date = September 2010 | pmid = 20833362 | pmc = 2952354 | doi = 10.1016/j.devcel.2010.08.014 }} {{cite journal | pmid = 3073266 | volume=16 | title=[Quantification of sebaceous excretion in volunteers: influence of chronological age, sex and race] | year=1988 | journal=Med Cutan Ibero Lat Am | pages=439–44 | vauthors=Villares JC, Carlini EA| issue=6 }} {{cite book | title=Developmental biology| edition=11th| author=Gilbert SF| year=2016| pages=269| publisher=Sinauer| isbn=9781605354705}}</ref>