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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. 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
Thelytoky
can occur by different mechanisms, each of which has a different impact on the level of homozygosity . It is found in several groups of Hymenoptera
Hymenoptera
, including Apidae
Apidae
, Aphelinidae , Cynipidae , Formicidae
Formicidae
, Ichneumonidae
Ichneumonidae
, and Tenthredinidae
Tenthredinidae
. It can be induced in Hymenoptera
Hymenoptera
by the bacteria Wolbachia
Wolbachia
and Cardinium.

CONTENTS

* 1 Arrhenotoky
Arrhenotoky
and thelytoky in Hymenoptera
Hymenoptera

* 2 Automixis

* 2.1 With central fusion * 2.2 With terminal fusion

* 3 See also * 4 References

ARRHENOTOKY AND THELYTOKY IN HYMENOPTERA

Honeybees produce haploid males from unfertilized eggs (arrhenotoky ).

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

AUTOMIXIS

The effects of central fusion and terminal fusion on heterozygosity

Automixis is a form of thelytoky. In automictic parthenogenesis , meiosis takes place and diploidy is restored by fusion of first division non-sister nuclei (central fusion) or the second division sister nuclei (terminal fusion). (see diagram).

WITH CENTRAL FUSION

Automixis with central fusion tends to maintain heterozygosity in the passage of the genome from mother to daughter. This form of automixis has been observed in several ant species including the desert ant Cataglyphis cursor , the clonal raider ant Cerapachys biroi
Cerapachys biroi
, the predaceous ant Platythyrea punctata , and the electric ant (little fire ant) Wasmannia auropunctata . Automixis with central fusion also occurs in the Cape honey bee Apis mellifera capensis
Apis mellifera capensis
, the brine shrimp Artemia parthenogenetica, and the termite Embiratermes neotenicus.

Oocytes that undergo automixis with central fusion often display a reduced rate of crossover recombination . A low rate of recombination in automictic oocytes favors maintenance of heterozygosity , and only a slow transition from heterozygosity to homozygosity over successive generations. This allows avoidance of immediate inbreeding depression . Species
Species
that display central fusion with reduced recombination include the ants P. punctata and W. auropunctata, the brine shrimp A. parthenogenetica, and the honey bee A. m. capensis. In A. m. capensis, the recombination rate during the meiosis associated with thelytokus parthenogenesis is reduced by more than 10-fold. In W. auropunctata the reduction is 45-fold.

Single queen colonies of the narrow headed ant Formica exsecta provide an illustrative example of the possible deleterious effects of increased homozygosity. In this ant the level of queen homozygosity is negatively associated with colony age. Reduced colony survival appears to be due to decreased queen lifespan resulting from queen homozygosity and expression of deleterious recessive mutations (inbreeding depression ).

WITH TERMINAL FUSION

Automixis with terminal fusion tends to promote homozygosity in the passage of the genome from mother to daughter. This form of automixis has been observed in the water flea Daphnia magna
Daphnia magna
and the Colombian rainbow boa constrictor Epicrates maurus . Parthenogenesis
Parthenogenesis
in E. maurus is only the third genetically confirmed case of consecutive virgin births of viable offspring from a single female within any vertebrate lineage. However, survival of offspring over two successive litters was poor, suggesting that automixis with terminal fusion leads to homozygosity and expression of deleterious recessive alleles (inbreeding depression ).

SEE ALSO

Look up THELYTOKY in Wiktionary, the free dictionary.

* Autotoky * Epitoky
Epitoky

REFERENCES

* ^ White, Michael J.D. (1984). "Chromosomal Mechanisms in Animal Reproduction". Bolletino di zoologia. 51 (1–2): 1–23. ISSN 0373-4137 . doi :10.1080/11250008409439455 . * ^ 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 . * ^ Jeong, G; R Stouthamer (2004-11-03). "Genetics of female functional virginity in the Parthenogenesis- Wolbachia
Wolbachia
infected parasitoid wasp Telenomus nawai (Hymenoptera: Scelionidae)" (PDF). Heredity. 94 (4): 402–407. ISSN 0018-067X . PMID 15523503 . doi :10.1038/sj.hdy.6800617 . Retrieved 2012-01-12. * ^ A B Pearcy, M. (2004). "Conditional Use of Sex and Parthenogenesis
Parthenogenesis
for Worker and Queen Production in Ants" (PDF). Science. 306 (5702): 1780–1783. PMID 15576621 . doi :10.1126/science.1105453 . * ^ 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. PMID 15988525 . doi :10.1038/nature03705 . * ^ A B C D Baudry E, Kryger P, Allsopp M, Koeniger N, Vautrin D, Mougel F, Cornuet JM, Solignac M (2004). "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. PMC 1470879  . PMID 15166151 . doi :10.1534/genetics.167.1.243 . * ^ A B C Kellner, Katrin; Heinze, Jürgen (2010). "Mechanism of facultative parthenogenesis in the ant Platythyrea punctata". Evolutionary Ecology. 25 (1): 77–89. doi :10.1007/s10682-010-9382-5 . * ^ Oxley PR, Ji L, Fetter-Pruneda I, McKenzie SK, Li C, Hu H, Zhang G, Kronauer DJ (2014). "The genome of the clonal raider ant Cerapachys biroi" . Current Biology. 24 (4): 451–8. PMC 3961065  . PMID 24508170 . doi :10.1016/j.cub.2014.01.018 . * ^ A B C Rey O, Loiseau A, Facon B, Foucaud J, Orivel J, Cornuet JM, Robert S, Dobigny G, Delabie JH, Mariano Cdos S, Estoup A (2011). "Meiotic recombination dramatically decreased in thelytokous queens of the little fire ant and their sexually produced workers". Molecular Biology and Evolution. 28 (9): 2591–601. PMID 21459760 . doi :10.1093/molbev/msr082 . * ^ A B Nougué O, Rode NO, Jabbour-Zahab R, Ségard A, Chevin LM, Haag CR, Lenormand T (2015). "Automixis in Artemia: solving a century-old controversy". Journal of Evolutionary Biology. 28 (12): 2337–48. PMID 26356354 . doi :10.1111/jeb.12757 . * ^ Fougeyrollas R, Dolejšová K, Sillam-Dussès D, Roy V, Poteaux C, Hanus R, Roisin Y (2015). "Asexual queen succession in the higher termite Embiratermes neotenicus" . Proceedings of the Royal Society of London B: Biological Sciences. 282 (1809): 20150260. PMC 4590441  . PMID 26019158 . doi :10.1098/rspb.2015.0260 . * ^ Haag-Liautard C, Vitikainen E, Keller L, Sundström L (2009). "Fitness and the level of homozygosity in a social insect". Journal of Evolutionary Biology. 22 (1): 134–42. PMID 19127611 . doi :10.1111/j.1420-9101.2008.01635.x . * ^ Svendsen N, Reisser CM, Dukić M, Thuillier V, Ségard A, Liautard-Haag C, Fasel D, Hürlimann E, Lenormand T, Galimov Y, Haag CR (2015). "Uncovering cryptic asexuality in Daphnia magna
Daphnia magna
by RAD sequencing" . Genetics. 201 (3): 1143–55. PMC 4649641  . PMID 26341660 . doi :10.1534/genetics.115.179879 . * ^ A B Booth W, Million L, Reynolds RG, Burghardt GM, Vargo EL, Schal C, Tzika AC, Schuett GW (2011). "Consecutive virgin births in the new world boid snake, the Colombian rainbow boa, Epicrates maurus". Journal of Heredity. 102 (6): 759–63. PMID 21868391 . doi :10.1093/jhered/esr080 .

* v * t * e

Eusociality
Eusociality

TOPICS

* Evolution of eusociality * Presociality

* Social insects

* Gamergate * Group selection * Haplodiploidy
Haplodiploidy
* Identity in social insects * Kin recognition * Kin selection * Sexual selection in social insects * Thelytoky * Worker policing

GROUPS

* Hymenoptera
Hymenoptera

* Ant
Ant
* Apidae
Apidae
* Crabronidae
Crabronidae
* Halictidae
Halictidae
* Honey bee
Honey bee
* Vespidae
Vespidae

* Mammalia
Mammalia

* Blesmol * Dwarf mongoose
Dwarf mongoose
* Meerkat
Meerkat

* Crustacea
Crustacea

* Synalpheus

* Thysanoptera
Thysanoptera

* Kladothrips

* Hemiptera
Hemiptera

* Aphididae

* Coleoptera
Coleoptera

* Austroplatypus incompertus

* Isoptera
Isoptera

IN CULTURE

* Bee
Bee
(mythology)

PIONEERS, WORKS

* Karl von Frisch
Karl von Frisch

* The Dancing Bees 1927

* Charles Duncan Michener
Charles Duncan Michener

* The Bees of the World 2000

* E. O. Wilson
E. O. Wilson

* The Ants 1990 * Sociobiology 1975

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Thelytoky
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