{"id":103,"date":"2015-02-25T16:08:29","date_gmt":"2015-02-25T21:08:29","guid":{"rendered":"http:\/\/www.yellowflower.xyz\/?page_id=103"},"modified":"2015-09-09T11:05:18","modified_gmt":"2015-09-09T15:05:18","slug":"parthenogenesis","status":"publish","type":"page","link":"http:\/\/www.yellowflower.xyz\/en\/samples\/parthenogenesis\/","title":{"rendered":"Parthenogenesis"},"content":{"rendered":"

(source text from here<\/a>)<\/p>\n

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Original<\/h3>\n

Life history types<\/h2>\n

Some species reproduce exclusively by parthenogenesis (such as the Bdelloid rotifers), while others can switch between sexual reproduction and parthenogenesis. This is called facultative parthenogenesis (other terms are cyclical parthenogenesis, heterogamy or heterogony). The switch between sexuality and parthenogenesis in such species may be triggered by the season (aphid, some gall wasps), or by a lack of males or by conditions that favour rapid population growth (rotifers and cladocerans like daphnia). In these species asexual reproduction occurs either in summer (aphids) or as long as conditions are favourable. This is because in asexual reproduction a successful genotype can spread quickly without being modified by sex or wasting resources on male offspring who won’t give birth. In times of stress, offspring produced by sexual reproduction may be fitter as they have new, possibly beneficial gene combinations. In addition, sexual reproduction provides the benefit of meiotic recombination between non-sister chromosomes, a process associated with repair of DNA double-strand breaks and other DNA damages that may be induced by stressful conditions.
\nMany taxa with heterogony have within them species that have lost the sexual phase and are now completely asexual. Many other cases of obligate parthenogenesis (or gynogenesis) are found among polyploids and hybrids where the chromosomes cannot pair for meiosis.
\nThe production of female offspring by parthenogenesis is referred to as thelytoky (e.g., aphids) while the production of males by parthenogenesis is referred to as arrhenotoky (e.g., bees). When unfertilized eggs develop into both males and females, the phenomenon is called deuterotoky.<\/p>\n<\/div>\n

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Translation<\/h3>\n

Tipos de hist\u00f3ria de vida<\/h2>\n

Algumas esp\u00e9cies, como os rot\u00edferos bdel\u00f3ides, se reproduzem exclusivamente por partenog\u00eanese, enquanto outras podem alternar reprodu\u00e7\u00e3o sexuada e partenog\u00eanese. Isto se chama partenog\u00eanese facultativa, tamb\u00e9m conhecida como partenog\u00eanese c\u00edclica, heterogamia ou heterogenia. A transi\u00e7\u00e3o entre sexualidade e partenog\u00eanese nestas esp\u00e9cies pode depender da \u00e9poca do ano (pulg\u00f5es, algumas vespas galhadoras) ou ser causada pela falta de machos ou por condi\u00e7\u00f5es favor\u00e1veis ao r\u00e1pido crescimento populacional (rot\u00edferos e clad\u00f3ceros, como Daphnia<\/i>). A reprodu\u00e7\u00e3o assexuada dessas esp\u00e9cies ocorre durante o ver\u00e3o (pulg\u00f5es) ou enquanto as condi\u00e7\u00f5es forem favor\u00e1veis. Com a reprodu\u00e7\u00e3o assexuada, um gen\u00f3tipo bem-sucedido pode se espalhar rapidamente sem ser alterado por sexo e sem desperdi\u00e7ar recursos com uma prole de machos incapazes de parir. Em per\u00edodos de estresse, \u00e9 poss\u00edvel que a prole gerada por reprodu\u00e7\u00e3o sexuada seja melhor adaptada, j\u00e1 que carregam combina\u00e7\u00f5es gen\u00e9ticas novas que podem ser ben\u00e9ficas. Al\u00e9m disso, a reprodu\u00e7\u00e3o sexuada confere o benef\u00edcio da recombina\u00e7\u00e3o mei\u00f3tica entre cromossomos hom\u00f3logos, um processo associado \u00e0 repara\u00e7\u00e3o das quebras da cadeia dupla de DNA e de outros danos ao DNA que podem ser induzidos por condi\u00e7\u00f5es estressantes.
\nMuitos grupos taxon\u00f4micos com heterogenia incluem esp\u00e9cies que perderam a fase sexual e se tornaram completamente assexuados. H\u00e1 muitos outros casos de partenog\u00eanese obrigat\u00f3ria (ou ginog\u00eanese) entre poliploides e h\u00edbridos em que os cromossomos n\u00e3o conseguem formar pares durante a meiose.
\nA produ\u00e7\u00e3o de prole feminina por partenog\u00eanese \u00e9 chamada de telitoquia (como nos pulg\u00f5es), enquanto a produ\u00e7\u00e3o de machos \u00e9 chamada de arrenotoquia (como nas abelhas). Casos em que ovos n\u00e3o fertilizados geram machos e f\u00eameas s\u00e3o chamados de deuterotoquia.<\/p>\n<\/div>\n

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(source text from here) Original Life history types Some species reproduce exclusively by parthenogenesis (such as the Bdelloid rotifers), while others can switch between sexual reproduction and parthenogenesis. This is called facultative parthenogenesis (other terms are cyclical parthenogenesis, heterogamy or heterogony). The switch between sexuality and parthenogenesis in such species may be triggered by the … Continue reading Parthenogenesis<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":67,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-103","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/pages\/103","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/comments?post=103"}],"version-history":[{"count":2,"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/pages\/103\/revisions"}],"predecessor-version":[{"id":152,"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/pages\/103\/revisions\/152"}],"up":[{"embeddable":true,"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/pages\/67"}],"wp:attachment":[{"href":"http:\/\/www.yellowflower.xyz\/en\/wp-json\/wp\/v2\/media?parent=103"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}