From Wikipedia, the free encyclopedia
Jump to: navigation, search

Thelytoky (from the Greek thēlys "female" and tokos "birth") is a type of parthenogenesis in which females are produced from unfertilized eggs, as for example in aphids. Thelytokous parthenogenesis is rare among animals and reported in about 1,500 species, about 1 in 1000 of described animal species, according to a 1984 study.[1] It is more common in invertebrates, like arthropods, but it can occur in vertebrates, including salamanders, fish, and reptiles such as some whiptail lizards.

Thelytoky can occur by a number of different mechanisms each of which has a different impact on the level of homozygosity. It can be induced in Hymenoptera by the bacteria Wolbachia and Cardinium,[2] and has also been described in several groups of Hymenoptera, including Cynipidae, Tenthredinidae, Aphelinidae, Ichneumonidae, Apidae and Formicidae.[3]

Thelytoky in ants, bees, and wasps[edit]

Hymenoptera (ants, bees, and wasps) have a haplodiploid sex-determination system. They produce haploid males from unfertilized eggs through arrhenotokous parthenogenesis. However, in a few social hymenopterans, queens or workers are capable of producing diploid female offspring by thelytoky.[4] The daughters produced may or may not be complete clones of their mother depending on the type of parthenogenesis that takes place.[5][6] The offspring can develop into either queens or workers. Examples of such species include the Cape bee, Apis mellifera capensis, Mycocepurus smithii and clonal raider ant, Cerapachys biroi.

See also[edit]


  1. ^ White, Michael J.D. (1984). "Chromosomal Mechanisms in Animal Reproduction" (PDF). Bolletino di zoologia 51 (1-2): 1–23. doi:10.1080/11250008409439455. ISSN 0373-4137. 
  2. ^ Jeong, G; R Stouthamer (2004-11-03). "Genetics of female functional virginity in the Parthenogenesis-Wolbachia infected parasitoid wasp Telenomus nawai (Hymenoptera: Scelionidae)" (PDF). Heredity 94 (4): 402–407. doi:10.1038/sj.hdy.6800617. ISSN 0018-067X. Retrieved 2012-01-12. 
  3. ^ Suomalainen, Esko; Anssi Saura; Juhani Lokki (1987-08-31). Cytology and evolution in parthenogenesis. CRC Press. pp. 29–31, 51. ISBN 978-0-8493-5981-1. 
  4. ^ Pearcy, M. (2004). "Conditional Use of Sex and Parthenogenesis for Worker and Queen Production in Ants" (PDF). Science 306 (5702): 1780–1783. doi:10.1126/science.1105453. ISSN 0036-8075. PMID 15576621. 
  5. ^ Fournier, Denis; Estoup, Arnaud; Orivel, Jérôme; Foucaud, Julien; Jourdan, Hervé; Breton, Julien Le; Keller, Laurent (2005). "Clonal reproduction by males and females in the little fire ant" (PDF). Nature 435 (7046): 1230–1234. doi:10.1038/nature03705. ISSN 0028-0836. PMID 15988525. 
  6. ^ Baudry, Emmanuelle; Per Kryger; Mike Allsopp; Nikolaus Koeniger; Dominique Vautrin; Florence Mougel; Jean-Marie Cornuet; Michel Solignac (2004-05-01). "Whole-Genome Scan in Thelytokous-Laying Workers of the Cape Honeybee (Apis mellifera capensis): Central Fusion, Reduced Recombination Rates and Centromere Mapping Using Half-Tetrad Analysis". Genetics 167 (1): 243–252. doi:10.1534/genetics.167.1.243. Retrieved 2012-01-12.