Vertebrate sexual systems

Written by: Bjørn Østman

Primary Source: Pleiotropy

Awesome figure of the sexual systems used by 2,145 vertebrates species (705 fish, 173 amphibian, 593 non-avian reptilian, 195 avian, 479 mammalian).Similar figures for plants and invertebrates.

Tree structure is derived from taxonomy, where each tip represents all species in a single genus.
Diploid chromosome number is indicated by the height of the innermost ring.
The XY/ZW ring is colored blue for XY and red for ZW taxa.
ESD = environmental sex determination.
The ‘Other’ ring includes parthenogenesis, gynogenesis, and hybridogenesis.
Complex SCS indicates species with complex sex chromosome karyotypes (e.g., X1X2Y).

  • All mammals are XY.
  • All birds are ZW.
  • Half-ish of all fish and no other vertebrates are hermaphrodites.
  • Only some fish and some reptiles are environmentally sex determined.

Ashman, T., Bachtrog, D., Blackmon, H., Goldberg, E., Hahn, M., Kirkpatrick, M., Kitano, J., Mank, J., Mayrose, I., Ming, R., Otto, S., Peichel, C., Pennell, M., Perrin, N., Ross, L., Valenzuela, N., and Vamosi, J. (2014). Tree of Sex: A database of sexual systems Scientific Data, 1 DOI: 10.1038/sdata.2014.15

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Bjørn Østman
Bjørn Østman is an evolutionary biologist postdoc working in the BEACON Center for the Study of Evolution in Action.
I am interested in many aspects of evolution. I work in computational biology, using various approaches to learn about fundamental processes of evolution. Bioinformatics is good for learning about real genes (data generously supplied by other researchers), and simulations are good for testing the mechanisms of evolution. I am particularly interested in how populations and organisms adapt to changing environments, both at the genetic and phenotypic level. Lately my research has focused on the evolutionary dynamics of populations evolving in rugged fitness landscapes.
Bjørn Østman

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