Arrhenotoky
{{Short description|Male-producing form of parthenogenesis}}
File:Haplodiploid Sex Determination in Honey Bees.svgs produce haploid males from unfertilized eggs]]
Arrhenotoky (from Greek ἄρρην árrhēn "male" and τόκος tókos "birth"), also known as arrhenotokous parthenogenesis, is a form of parthenogenesis in which unfertilized eggs develop into males. In most cases, parthenogenesis produces exclusively female offspring, hence the distinction.
Overview
The set of processes included under the term arrhenotoky depends on the author:{{Cite journal | last1 = Normark | first1 = B. B. | doi = 10.1146/annurev.ento.48.091801.112703 | title = The evolution of alternative genetic systems in insects| journal = Annual Review of Entomology | volume = 48 | pages = 397–423 | year = 2003 | pmid = 12221039}} arrhenotoky may be restricted to the production of males that are haploid (haplodiploidy); may include diploid males that permanently inactivate one set of chromosomes (parahaploidy); or may be used to cover all cases of males being produced by parthenogenesis (including such cases as aphids, where the males are XO diploids). The form of parthenogenesis in which females develop from unfertilized eggs is known as thelytoky; when both males and females develop from unfertilized eggs, the term "deuterotoky" is used.{{cite journal| last1= Gavrilov | first1 = I.A. | last2 = Kuznetsova | first2 = V.G. | title =On some terms used in the cytogenetics and reproductive biology of scale insects (Homoptera: Coccinea) |journal = Comparative Cytogenetics | year = 2007 | volume = 1 | issue= 2 |pages = 169–174 | issn = 1993-078X | url=http://www.zin.ru/Journals/compcyt/pdf/1/GavrilovKuznetsova.pdf}}
In the most commonly used sense of the term, arrhenotoky is synonymous with haploid arrhenotoky or haplodiploidy: the production of haploid males from unfertilized eggs in insects having a haplodiploid sex-determination system. Males are produced parthenogenetically, while diploid females are usually{{efn|Unless in certain rare cases they too are produced by thelytokous parthenogenesis.{{Cite journal | last1 = Pearcy | first1 = M. | last2 = Aron | first2 = S. | last3 = Doums | first3 = C. | last4 = Keller | first4 = L. | title = Conditional Use of Sex and Parthenogenesis for Worker and Queen Production in Ants | doi = 10.1126/science.1105453 | journal = Science | volume = 306 | issue = 5702 | pages = 1780–1783 | year = 2004 | pmid = 15576621| bibcode = 2004Sci...306.1780P | s2cid = 37558595 | url = https://serval.unil.ch/notice/serval:BIB_B02C2CCCBCB4 }}}} produced biparentally from fertilized eggs. In a similar phenomenon, parthenogenetic diploid eggs develop into males by converting one set of their chromosomes to heterochromatin, thereby inactivating those chromosomes.{{Cite journal | last1 = Nur | first1 = U. | title = Diploid arrhenotoky and automictic thelytoky in soft scale insects (Lecaniidae: Coccoidea: Homoptera) | doi = 10.1007/BF00326174 | journal = Chromosoma | volume = 39 | issue = 4 | pages = 381–401 | year = 1972 | s2cid = 23071909 }} This is referred to as diploid arrhenotoky or parahaploidy.{{Cite journal | last1 = Nur | first1 = U.| title = Parthenogenesis in Coccids (Homoptera) | doi = 10.1093/icb/11.2.301 | journal = Integrative and Comparative Biology | volume = 11 | issue = 2 | pages = 301–308 | year = 1971 |jstor = 3881755| doi-access = free }}
Arrhenotoky occurs in members of the insect order Hymenoptera (bees, ants, and wasps){{Cite book | publisher = Cambridge University Press | isbn = 9780521821490 | last = Grimaldi | first = David A. |author2=Michael S. Engel | title = Evolution of the Insects | url = https://archive.org/details/evolutioninsects00grim_110 | url-access = limited | date = 2005-05-16 | page = [https://archive.org/details/evolutioninsects00grim_110/page/n422 408]}} and the Thysanoptera (thrips).{{Cite journal| doi = 10.1080/11250008409439455| issn = 0373-4137| volume = 51| issue = 1–2| pages = 1–23| last = White| first = Michael J.D.| title = Chromosomal mechanisms in animal reproduction| journal = Bolletino di Zoologia| year = 1984|type = free full text}} The system also occurs sporadically in some spider mites, Hemiptera, Coleoptera (bark beetles), Scorpiones (Tityus metuendus) and rotifers.
See also
Notes
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