asexual generation


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generation

 [jen″er-a´shun]
1. the process of reproduction.
2. a class composed of all individuals removed by the same number of successive ancestors from a common predecessor, or occupying positions on the same level in a genealogical (pedigree) chart.
alternate generation reproduction by alternate asexual and sexual means in an animal or plant species.
asexual generation (direct generation) production of a new organism not originating from union of gametes.
first filial generation the first-generation offspring of two parents; symbol F1.
parental generation the generation with which a particular genetic study is begun; symbol P1.
second filial generation all of the offspring produced by two individuals of the first filial generation; symbol F2.
sexual generation production of a new organism from the cell formed by the union of a male gamete (spermatozoon) and a female gamete (oocyte).
spontaneous generation the discredited concept of continuous generation of living organisms from nonliving matter.

a·sex·u·al gen·er·a·tion

reproduction by fission, gemmation, or in any other way without union of the male and female cell, or conjugation.
See also: parthenogenesis.

a·sex·u·al gen·er·a·tion

(ā-sek'shū-ăl jen-ĕr-ā'shŭn)
Reproduction by fission, gemmation, or in any other way without union of the male and female cells, or conjugation.
See also: parthenogenesis
Synonym(s): heterogenesis (2) , nonsexual generation.
References in periodicals archive ?
Pringsheim denied that the fruits of thallophytes were in any sense homologous to the asexual generation of mosses.
This change would accentuate the alternative routes that were proposed for the origin of the asexual generation of land plants (Bower, 1935; p.
Embryos at earlier developmental stages would have had insufficient time to complete development before the colony began a new asexual generation and the old zooids were resorbed (Stewart-Savage et al., 2001a).
Embryos at an earlier developmental stage at the conclusion of our sample intervals would probably not have had sufficient time to complete development before the adult zooids were resorbed and the next asexual generation began (Stewart-Savage et al., 2001a).
In this notation, "every one generation" corresponds to zero asexuality, "every three generations" corresponds to a pattern of two asexual generations followed by one sexual generation, and so on.
For these simulations, we considered mutation rates ranging from U = 0.02 to U = 0.5, assuming for simplicity a single mutation rate for both sexual and asexual generations. Although meiotic mutation rates have been estimated to be several times higher than mitotic mutation rates (Magni and von Borstel 1962; Lindgren 1975), the ultimate effect of this difference on mutation rates in sexual and asexual generations is considerably smaller, because both forms of reproduction undergo many mitotic divisions between generations.