Organism with both male and female characteristics
A gynandromorph is an organism that contains both male and female characteristics. The term comes from the Greek γυνή (gynē) 'female', ἀνήρ (anēr) 'male', and μορφή (morphē) 'form', and is used mainly in the field of entomology. Gynandromorphism is most frequently recognized in organisms that have strong sexual dimorphism such as certain butterflies, spiders, and birds, but has been recognized in numerous other types of organisms.
Pattern of distribution of male and female tissues in a single organism
A gynandromorph can have bilateral symmetry—one side female and one side male.[24] Alternatively, the distribution of male and female tissue can be more haphazard. Bilateral gynandromorphy arises very early in development, typically when the organism has between 8 and 64 cells.[25] Later stages produce a more random pattern.[citation needed]
A notable example in birds is the zebra finch. These birds have lateralised brain structures in the face of a common steroid signal, providing strong evidence for a non-hormonal primary sex mechanism regulating brain differentiation.[26]
The cause of this phenomenon is typically (but not always) an event in mitosis during early development. While the organism contains only a few cells, one of the dividing cells does not split its sex chromosomes typically. This leads to one of the two cells having sex chromosomes that cause male development and the other cell having chromosomes that cause female development. For example, an XY cell undergoing mitosis duplicates its chromosomes, becoming XXYY. Usually this cell would divide into two XY cells, but in rare occasions the cell may divide into an X cell and an XYY cell. If this happens early in development, then a large portion of the cells are X and a large portion are XYY. Since X and XYY dictate different sexes, the organism has tissue that is female and tissue that is male.[27]
A developmental network theory of how gynandromorphs develop from a single cell based on a working paper links between parental allelicchromosomes was proposed in 2012.[28] The major types of gynandromorphs, bilateral, polar and oblique are computationally modeled. Many other possible gynandromorph combinations are computationally modeled, including predicted morphologies yet to be discovered. The article relates gynandromorph developmental control networks to how species may form. The models are based on a computational model of bilateral symmetry.[29]
As a research tool
Gynandromorphs occasionally afford a powerful tool in genetic, developmental, and behavioral analyses. In Drosophila melanogaster, for instance, they provided evidence that male courtship behavior originates in the brain,[30] that males can distinguish conspecific females from males by the scent or some other characteristic of the posterior, dorsal, integument of females,[31][32] that the germ cells originate in the posterior-most region of the blastoderm,[33] and that somatic components of the gonads originate in the mesodermal region of the fourth and fifth abdominal segment.[34]
^Labruna, M. B.; Ribeiro, A. F.; Cruz, M. V.; Camargo, L. M A.; Camargo, E. P. (August 2002). "Gynandromorphism in Amblyomma cajennense and Rhipicephalus sanguineus (Acari: Ixodidae)". Journal of Parasitology. 88 (4): 810–811. doi:10.1645/0022-3395(2002)088[0810:GIACAR]2.0.CO;2. PMID12197141. S2CID26299983.
^Morgan, T. H. (1 June 1914). "Mosaics and gynandromorphs in Drosophila". Experimental Biology and Medicine. 11 (6): 171–172. doi:10.3181/00379727-11-105. S2CID87401593.
^Maeno, Koutaro; Tanaka, Seiji (September 2007). "Morphological and behavioural characteristics of a gynandromorph of the desert locust, Schistocerca gregaria". Physiological Entomology. 32 (3): 294–299. doi:10.1111/j.1365-3032.2007.00573.x. S2CID85317122.
^Taniyama, Katsuya; Onodera, Kaori; Tanaka, Kazuhiro (December 2018). "Sexual identity and sexual attractiveness of a gynandromorph of the lawn ground cricket, Polionemobius mikado (Orthoptera: Trigonidiidae): Gynandromorph of Polionemobius mikado". Entomological Science. 21 (4): 423–427. doi:10.1111/ens.12321. S2CID91381517.
^Mitchell, Joseph C.; Fouquette, M. J. (10 February 1978). "A Gynandromorphic Whiptail Lizard, Cnemidophorus inornatus, from Arizona". Copeia. 1978 (1): 156. doi:10.2307/1443840. JSTOR1443840.
^Krohmer, Randolph W. (27 December 1989). "Reproductive Physiology and Behavior of a Gynandromorph Redsided Garter Snake, Thamnophis sirtalis parietalis, from Central Manitoba, Canada". Copeia. 1989 (4): 1064–1068. doi:10.2307/1446001. JSTOR1446001.
^Hollander, W. F.; Gowen, John W.; Stadler, Janice (February 1956). "A study of 25 gynandromorphic mice of the Bagg albino strain". The Anatomical Record. 124 (2): 223–243. doi:10.1002/ar.1091240207. PMID13302819. S2CID21938150.
^Adams, James K. "Gynandromorphs". Department of Natural Sciences, Dalton State College. Archived from the original on 2013-03-07. Retrieved 2005-06-29.
^Werner, Eric (2012). "A Developmental Network Theory of Gynandromorphs, Sexual Dimorphism and Species Formation". arXiv:1212.5439 [q-bio.MN].
^Werner, Eric (2012). "The Origin, Evolution and Development of Bilateral Symmetry in Multicellular Organisms". arXiv:1207.3289 [q-bio.TO].