Gonochorism Explained

In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female.[1] The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric.[2]

Gonochorism contrasts with simultaneous hermaphroditism but it may be hard to tell if a species is gonochoric or sequentially hermaphroditic e.g. parrotfish, Patella ferruginea.[3] However, in gonochoric species individuals remain either male or female throughout their lives.[4] Species that reproduce by thelytokous parthenogenesis and do not have males can still be classified as gonochoric.[5]

Terminology

The term is derived from Greek (gone, generation) + (chorizein, to separate).[6] The term gonochorism originally came from German Gonochorismus.[7]

Gonochorism is also referred to as unisexualism or gonochory.

Evolution

Gonochorism has evolved independently multiple times.[8] It is very evolutionarily stable in animals.[9] Its stability and advantages have received little attention.[10] Gonochorism owes its origin to the evolution of anisogamy,[11] but it is unclear if the evolution of anisogamy first led to hermaphroditism or gonochorism.

Gonochorism is thought to be the ancestral state in polychaetes, hexacorallia,[12] nematodes,[13] and hermaphroditic fishes. Gonochorism is thought to be ancestral in hermaphroditic fishes because it is widespread in basal clades of fish and other vertebrate lineages.[14]

Two papers from 2008 have suggested that transitions between hermaphroditism and gonochorism or vice versa have occurred in animals between 10 and 20 times.[15] In a 2017 study involving 165 taxon groups, more evolutionary transitions from gonochorism to hermaphroditism were found than the reverse.[16]

Use across species

Animals

The term is most often used with animals, in which the species are usually gonochoric.

Gonochorism has been estimated to occur in 95% of animal species.[17] It is very common in vertebrate species, 99% of which are gonochoric.[18] [19] 98% of fishes are gonochoric.[20] Mammals (including humans[21] [22]) and birds are solely gonochoric.[23]

Tardigrades are almost always gonochoric.[24] 75% of snails are gonochoric.[25]

Most arthropods are gonochoric.[26] For example a majority of crustaceans are gonochoric.[27]

In animals, sex is most often genetically determined, but may be determined by other mechanisms. For example, alligators use temperature-dependent sex determination during egg incubation.

Plants

Plants which have single-sex individuals are typically called dioecious (vascular plants)[28] or dioicous (bryophytes)[29] instead of gonochoric. In flowering plants, individual flowers may be hermaphroditic (i.e. with both stamens and ovaries) or dioecious (unisexual), having either no stamens (i.e. no male parts) or no ovaries (i.e. no female parts). Among flowering plants with unisexual flowers, some also produce hermaphrodite flowers, and the three types may occur in different arrangements on the same or separate plants. Plant species can thus be hermaphrodite, monoecious, dioecious, trioecious, polygamomonoecious, polygamodioecious, andromonoecious, or gynomonoecious.

Examples of species with gonochoric or dioecious pollination include hollies and kiwifruit. In these plants the male plant that supplies the pollen is referred to as the pollenizer.

Other reproductive strategies

Gonochorism stands in contrast to other reproductive strategies such as asexual reproduction and hermaphroditism. Closely related taxa can have differing sexual strategies – for example, the genus Ophryotrocha contains species that are gonochoric and species that are hermaphrodites.[30]

The sex of an individual may also change during its lifetimethis sequential hermaphroditism can, for example, be found in parrotfish[31] [32] and cockles.

See also

Notes and References

  1. Book: A Dictionary of Genetics . King RC, Stansfield WD, Mulligan PK . 2006-07-27 . Oxford University Press . 978-0-19-976957-5 . 187 . en . Gonochorism . subscription . 2021-06-11 . 2021-06-11 . https://web.archive.org/web/20210611220101/https://www.oxfordreference.com/view/10.1093/acref/9780195307610.001.0001/acref-9780195307610-e-2626 . live .
  2. Book: Encyclopedia of Evolutionary Biology . Kliman RM . 2016 . Academic Press . 978-0-12-800426-5 . Schärer L, Ramm S . 2 . Hermaphrodites . https://web.archive.org/web/20240328080956/https://books.google.com/books?id=_r4OCAAAQBAJ . 2024-03-28 . 2021-08-05 . bot: unknown .
  3. Book: Encyclopedia of Animal Cognition and Behavior . Holub AM, Shackelford TK . Todd K. Shackelford . 2020 . Springer International Publishing . 978-3-319-47829-6 . Vonk J, Shackelford TK . Cham . 1–3 . en . Gonochorism . 10.1007/978-3-319-47829-6_305-1 . 240938739 . 2021-05-02 . 2021-04-26 . https://web.archive.org/web/20210426192450/https://www.toddkshackelford.com/downloads/Holub-Shackelford-Gonochorism-EACB-2021.pdf . live .
  4. Book: Stuart West . Sex Allocation . West S . 2009-09-28 . Princeton University Press . 978-1-4008-3201-9 . 1 . en.
  5. Book: The Biology of Reproduction . Fusco G, Minelli A . 2019-10-10 . Cambridge University Press . 978-1-108-49985-9 . 116–117 . en.
  6. Book: Winn, Philip . Dictionary of Biological Psychology . 2003-09-02 . Routledge . 978-1-134-77815-7 . 698 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002313/https://books.google.com/books?id=OEMSWCeeSPYC&dq=gonochorism+dictionary&pg=PA698#v=onepage&q=gonochorism%20dictionary&f=false . live .
  7. Web site: Definition of GONOCHORISM . 2021-09-29 . www.merriam-webster.com . en . 2021-09-29 . https://web.archive.org/web/20210929141705/https://www.merriam-webster.com/dictionary/gonochorism . live .
  8. 6 . Bachtrog D, Mank JE, Peichel CL, Kirkpatrick M, Otto SP, Ashman TL, Hahn MW, Kitano J, Mayrose I, Ming R, Perrin N, Ross L, Valenzuela N, Vamosi JC . July 2014 . Sex determination: why so many ways of doing it? . PLOS Biology . 12 . 7 . e1001899 . 10.1371/journal.pbio.1001899 . 4077654 . 24983465 . free.
  9. Leonard . Janet L. . 2013-10-01 . Williams' Paradox and the Role of Phenotypic Plasticity in Sexual Systems . Integrative and Comparative Biology . 53 . 4 . 671–688 . 10.1093/icb/ict088 . 1540-7063 . 23970358 . free.
  10. Book: Transitions Between Sexual Systems: Understanding the Mechanisms of, and Pathways Between, Dioecy, Hermaphroditism and Other Sexual Systems . Leonard JL . 2019-05-21 . Springer . 978-3-319-94139-4 . en . 2021-07-12 . 2024-04-17 . https://web.archive.org/web/20240417002409/https://books.google.com/books?id=0rWZDwAAQBAJ&q=sexual+system#v=snippet&q=sexual%20system&f=false . live .
  11. Book: Barnes, R. S. K. . An Introduction to Marine Ecology . Hughes . R. N. . 1999-06-02 . John Wiley & Sons . 978-0-86542-834-8 . 202 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002434/https://books.google.com/books?id=L_UETIhX2sAC&dq=gonochorism+evolution&pg=PA202#v=onepage&q=gonochorism%20evolution&f=false . live .
  12. Book: Dubinsky, Zvy . Coral Reefs: An Ecosystem in Transition . Stambler . Noga . 2010-12-02 . Springer Science & Business Media . 978-94-007-0114-4 . en . 2022-07-27 . 2023-04-19 . https://web.archive.org/web/20230419094504/https://books.google.com/books?id=4hI5XCcYzUgC&dq=gonochorism+ancestral&pg=PA74 . live .
  13. Book: Schmidt-Rhaesa, Andreas . Nematoda . 2013-12-18 . Walter de Gruyter . 978-3-11-027425-7 . en . 2022-07-27 . 2023-04-19 . https://web.archive.org/web/20230419094458/https://books.google.com/books?id=FJfoBQAAQBAJ&dq=gonochorism+evolved+independently+10+times&pg=PA62 . live .
  14. Erisman BE, Petersen CW, Hastings PA, Warner RR . October 2013 . Phylogenetic perspectives on the evolution of functional hermaphroditism in teleost fishes . Integrative and Comparative Biology . 53 . 4 . 736–54 . 10.1093/icb/ict077 . 23817661 . free.
  15. Weeks . Stephen C. . 18 June 2012 . The Role of Androdioecy and Gynodioecy in Mediating Evolutionary Transitions Between Dioecy and Hermaphroditism in the Animalia . Evolution . en . 66 . 12 . 3670–3686 . 10.1111/j.1558-5646.2012.01714.x . 23206127 . 3198554 . 12 July 2022 . 15 June 2022 . https://web.archive.org/web/20220615211222/https://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2012.01714.x . live .
  16. Sasson DA, Ryan JF . December 2017 . A reconstruction of sexual modes throughout animal evolution . BMC Evolutionary Biology . 17 . 1 . 242 . 2017BMCEE..17..242S . 10.1186/s12862-017-1071-3 . 5717846 . 29207942 . free.
  17. Muyle A, Bachtrog D, Marais GA, Turner JM . June 2021 . Epigenetics drive the evolution of sex chromosomes in animals and plants . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 376 . 1826 . 20200124 . 10.1098/rstb.2020.0124 . 8059572 . 33866802.
  18. Book: Michael Skinner (biologist) . Encyclopedia of Reproduction . Skinner M . 2018-06-29 . Academic Press . 978-0-12-815145-7 . Pan Q, Guiguen Y, Herpin A . 168 . en . Evolution of Sex Determining Genes in Fish . https://books.google.com/books?id=m4RlDwAAQBAJ&pg=RA5-PA168 . 2021-06-01 . 2024-04-17 . https://web.archive.org/web/20240417002506/https://books.google.com/books?id=m4RlDwAAQBAJ&pg=RA5-PA168#v=onepage&q&f=false . live .
  19. Kuwamura T, Sunobe T, Sakai Y, Kadota T, Sawada K . 2020-07-01 . Hermaphroditism in fishes: an annotated list of species, phylogeny, and mating system . Ichthyological Research . en . 67 . 3 . 341–360 . 2020IchtR..67..341K . 10.1007/s10228-020-00754-6 . 1616-3915 . free.
  20. Book: Pandian, T. J. . Thavamani Jegajothivel Pandian . Sex Determination in Fish . 2011-09-02 . CRC Press . 978-1-4398-7919-1 . 8 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002517/https://books.google.com/books?id=eAjSBQAAQBAJ&dq=gonochorism+estimates&pg=PA8#v=onepage&q=gonochorism%20estimates&f=false . live .
  21. Book: Genetics: A Conceptual Approach . Pierce BA . 2012 . Macmillan . 978-1-4292-3252-4 . 75 . en . 2021-07-12 . 2024-04-17 . https://web.archive.org/web/20240417002532/https://books.google.com/books?id=z4pXRaZAkdkC&q=humans+are+dioecious+genetics&pg=PA75#v=snippet&q=humans%20are%20dioecious%20genetics&f=false . live .
  22. Book: Human Evolutionary Biology . Muehlenbein MP . 2010-07-29 . Cambridge University Press . 978-0-521-87948-4 . Jones J . 74 . en . 2021-07-12 . 2024-04-17 . https://web.archive.org/web/20240417002509/https://books.google.com/books?id=1VXX1jkhPH8C&q=humans+are+dioecious+biology&pg=PT57#v=snippet&q=humans%20are%20dioecious%20biology&f=false . live .
  23. Book: Reproductive and Developmental Strategies: The Continuity of Life . Kobayashi K, Kitano T, Iwao Y, Kondo M . June 2018 . Springer . 978-4-431-56609-0 . 290 . en . 2021-05-05 . 2024-04-17 . https://web.archive.org/web/20240417002524/https://books.google.com/books?id=g4teDwAAQBAJ&q=mammal+gonochorism&pg=PA290#v=snippet&q=mammal%20gonochorism&f=false . live .
  24. Book: Thorp, James H. . Ecology and Classification of North American Freshwater Invertebrates . Covich . Alan P. . 2010 . Academic Press . 978-0-12-374855-3 . 468 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002541/https://books.google.com/books?id=iOI9ifbikoQC&dq=gonochorism+invertebrates&pg=PA468#v=onepage&q=gonochorism%20invertebrates&f=false . live .
  25. Book: Encyclopedia of Evolutionary Biology . 2016-04-14 . Academic Press . 978-0-12-800426-5 . 4 . 50 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002538/https://books.google.com/books?id=_r4OCAAAQBAJ&q=gonochorism+encyclopedia#v=snippet&q=gonochorism%20encyclopedia&f=false . live .
  26. Book: Giribet, Gonzalo . The Invertebrate Tree of Life . Edgecombe . Gregory D. . 2020-03-03 . Princeton University Press . 978-0-691-19706-7 . 249 . en.
  27. Book: Subramoniam, Thanumalaya . Sexual Biology and Reproduction in Crustaceans . 2016-09-27 . Academic Press . 978-0-12-809606-2 . 57–58 . en . 2021-11-30 . 2024-04-17 . https://web.archive.org/web/20240417002541/https://books.google.com/books?id=ztUCDAAAQBAJ&q=evolution+of+hermaphroditism#v=snippet&q=evolution%20of%20hermaphroditism&f=false . live .
  28. Book: Beentje, Henk . The Kew Plant Glossary . . 2016 . 978-1-84246-604-9 . 2 . Richmond, Surrey.
  29. Villarreal . Juan Carlos . Renner . Susanne S. . 2013 . Correlates of monoicy and dioicy in hornworts, the apparent sister group to vascular plants . BMC Evolutionary Biology . 13 . 1 . 239 . 2013BMCEE..13..239V . 10.1186/1471-2148-13-239 . 4228369 . 24180692 . free.
  30. Prevedelli D, N'Siala GM, Simonini R . January 2006 . Gonochorism vs. hermaphroditism: relationship between life history and fitness in three species of Ophryotrocha (Polychaeta: Dorvilleidae) with different forms of sexuality . The Journal of Animal Ecology . 75 . 1 . 203–12 . 2006JAnEc..75..203P . 10.1111/j.1365-2656.2006.01040.x . 16903057 . free.
  31. Web site: Stoplight parrotfish . dead . https://web.archive.org/web/20091206221521/http://www.flmnh.ufl.edu:80/fish/Gallery/Descript/SParrotfish/SParrotfish.html . 6 December 2009 . 15 December 2009 . Florida Museum of Natural History, Ichthyology Department . Bester C.
  32. Afonso P, Morato T, Santos RS . 2008 . Spatial patterns in reproductive traits of the temperate parrotfish Sparisoma cretense. . Fisheries Research . 90 . 1–3 . 92–99 . 10.1016/j.fishres.2007.09.029.

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