Editing Snake (section)

=== Facultative parthenogenesis ===
[[Parthenogenesis]] is a natural form of reproduction in which growth and development of embryos occur without fertilization. ''Agkistrodon contortrix'' (copperhead) and ''Agkistrodon piscivorus'' (cottonmouth) can reproduce by [[Parthenogenesis#Facultative|facultative parthenogenesis]], meaning that they are capable of switching from a [[Sexual reproduction|sexual]] mode of reproduction to an [[Asexual reproduction|asexual]] mode.<ref name=Booth2012>{{cite journal |vauthors=Booth W, Smith CF, Eskridge PH, Hoss SK, Mendelson JR, Schuett GW |title=Facultative parthenogenesis discovered in wild vertebrates |journal=[[Biology Letters]] |volume=8 |issue=6 |pages=983–5 |date=December 2012 |pmid=22977071 |pmc=3497136 |doi=10.1098/rsbl.2012.0666}}</ref> The most likely type of parthenogenesis to occur is [[Parthenogenesis#Automictic|automixis]] with terminal fusion, a process in which two terminal products from the same [[meiosis]] fuse to form a diploid [[zygote]]. This process leads to genome-wide [[Zygosity#Homozygous|homozygosity]], expression of deleterious recessive [[allele]]s, and often to developmental abnormalities. Both captive-born and wild-born copperheads and cottonmouths appear to be capable of this form of parthenogenesis.<ref name=Booth2012 />

Reproduction in [[Squamata|squamate]] reptiles is almost exclusively sexual. Males ordinarily have a ZZ pair of sex-determining chromosomes, and females a ZW pair. However, the Colombian Rainbow boa (''[[Epicrates maurus]]'') can also reproduce by facultative parthenogenesis, resulting in production of WW female progeny.<ref name="pmid21868391">{{cite journal |author6-link=Coby Schal |vauthors=Booth W, Million L, Reynolds RG, Burghardt GM, Vargo EL, Schal C, Tzika AC, Schuett GW |display-authors=6 |title=Consecutive virgin births in the new world boid snake, the Colombian rainbow Boa, Epicrates maurus |journal=The Journal of Heredity |volume=102 |issue=6 |pages=759–63 |year=2011 |pmid=21868391 |doi=10.1093/jhered/esr080 |doi-access=free}}</ref> The WW females are likely produced by terminal automixis.{{Citation needed|date=November 2024}}