Editing Gynandromorphism (section)

== Causes ==
The exact cause for gynandromorphism is unknown, and appears to vary by species.<ref name=":0" /> One proposed cause for the phenotype in birds is a disruption that occurs in [[meiosis]] in female birds -- who possess [[ZW sex-determination system|ZW chromosomes]] -- in which [[Polar body|polar bodies]] are not forced out of the cell.<ref name=":2">{{Cite journal |last1=Morris |first1=Kirsten R |last2=Hirst |first2=Claire E. |last3=Major |first3=Andrew T. |last4=Ezaz |first4=Tariq |last5=Ford |first5=Mark |last6=Bibby |first6=Susan |last7=Doran |first7=Tim J. |last8=Smith |first8=Craig A. |date=15 August 2018 |title=Gonadal and Endocrine Analysis of a Gynandromorphic Chicken |url=https://academic.oup.com/endo/article/159/10/3492/5074254 |journal=Endocrinology |volume=159 |issue=10 |pages=3492–3502 |doi=10.1210/en.2018-00553 |pmid=30124802 |via=Oxford Academic}}</ref> This is then followed with [[Fertilisation|fertilization]] by two Z-bearing [[Sperm|sperm cells]] which creates cells in the embryo containing both ZZ and ZW chromosomes.<ref name=":2" /> The same phenomenon can be seen in other species, such as ''[[Drosophila melanogaster]]'', and creates a [[Mosaic (genetics)|genetic mosaic]] which gives rise to the mixed phenotype.