parthenogenesis

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parthenogenesis

 [pahr″thĕ-no-jen´ĕ-sis]
a modified form of sexual reproduction in which a gamete develops into a new individual without the fertilization of an oocyte by a spermatozoon, as in certain arthropods and other animals; it may occur as a natural phenomenon or be induced by chemical or mechanical stimulation (artificial parthenogenesis). adj., adj parthenogenet´ic.

par·the·no·gen·e·sis

(par'the-nō-jen'ĕ-sis),
A form of nonsexual reproduction, or agamogenesis, in which the female reproduces its kind without fecundation by the male.
[G. parthenos, virgin, + genesis, product]

parthenogenesis

(pär′thə-nō-jĕn′ĭ-sĭs)
n.
1. A form of reproduction in which an unfertilized egg develops into a new individual, occurring commonly among insects and certain other arthropods.
2. The artificial activation of an unfertilized usually mammalian egg, resulting in an embryolike cell cluster from which stem cells can be harvested.

par′the·no·ge·net′ic (-jə-nĕt′ĭk), par′the·no·gen′ic (-jĕn′ĭk) adj.
par′the·no·ge·net′i·cal·ly adv.

parthenogenesis

[pär′thənōjen′əsis]
Etymology: Gk, parthenos, virgin, genesis, origin
a type of nonsexual reproduction in which an organism develops from an unfertilized ovum, as in many simpler animals. The development of the unfertilized ovum may be artificially induced through mechanical or chemical stimulation. Also called unicellular reproduction. parthenogenetic, parthenogenic, adj.

par·the·no·gen·e·sis

(pahr'thĕ-nō-jen'ĕ-sis)
A form of nonsexual reproduction, or agamogenesis, in which the female reproduces its kind without fecundation by the male.
[G. parthenos, virgin, + genesis, product]

parthenogenesis

The development of an unfertilized egg into an adult organism. Virgin birth. This occurs naturally in bees and ants and in some animal species development of an ovum can be induced chemically or by pricking with a fine glass fibre. The result is a clone of the mother cell identical in all respects. Only females can be produced by parthenogenesis, as no Y chromosome is present. If achieved, human parthenogenesis would make men biologically redundant. Very early human embryos derived only from ova have been produced experimentally by a parthenogenetic technique using chemicals that changed the concentration of ions in the ova.

parthenogenesis

the development of an individual from an egg without fertilization by a sperm. The process occurs mainly in lower invertebrates, particularly insects. The egg cell can be HAPLOID (1) to produce, for example, male honeybees (drones) or DIPLOID (1) as produced in wingless female aphids which, during the summer months, produce diploid eggs by MITOSIS that develop into female adults, only forming haploid gametes by MEIOSIS in the autumn prior to normal sexual reproduction.

parthenogenesis

asexual reproduction in which an egg develops without being fertilized by a spermatozoon, as in certain lower animals, especially arthropods; it may occur as a natural phenomenon or be induced by chemical or mechanical stimulation (artificial parthenogenesis).
References in periodicals archive ?
de Flores Frutos flores fecundadas maduros utilizadas Controle (polinizacao natural) 20 13 (65%) 12 (60%) Xenogamia (polinizacao cruzada) 20 13 (65%) 9 (45%) Autopolinizacao manual 20 5 (25%) 2 (10%) Autopolinizacao espontanea 20 3 (15%) 2 (10%) Apomixia 20 0 (0%) 0 (0%) Geitonogamia 20 2 (20%) 1 (5%) Indice de autoincompatibilidade (ISI) 0,22 Indice de autopolinizacao espontanea (ISA) 1,0 Eficacia reprodutiva (ER) 1,33
Somente arvores com flores femininas sao encontradas nas areas de cultivo, sendo as sementes formadas por apomixia (YAACOB; TINDALL, 1995).
A embrionia adventicia esporofitica (poliembrionia), um tipo de apomixia (reproducao assexual por semente), e comum em muitos genotipos de citros e cujo controle genetico e complexo, envolvendo pelo menos um gene (ALESA et al.
Nas sementes poliembrionicas, normalmente, ha um embriao zigotico, formado pela fecundacao, e um ou mais embrioes assexuais, formados por apomixia (embriogenese somatica), os quais geram plantas que sao clones da planta-mae.