نتایج جستجو برای: parthenogenesis
تعداد نتایج: 892 فیلتر نتایج به سال:
Males and females are in conflict over genetic transmission in the evolution of parthenogenesis, because it enhances female reproductive output but deprives the males' genetic contribution. For males, any trait that coerces females into sexual reproduction should increase their fitness. However, in the termite Reticulitermes speratus, queens produce their replacements (neotenic queens) partheno...
The short-term advantages of sexual reproduction are unclear, but the existence of groups that are capable of producing either meiotic or ameiotic eggs (cyclic parthenogenesis, CP) might indicate that short-term advantages to sex exist. Alternatively, CP might be an unstable transitory stage between asexuality and sex, or a phylogenetically favoured life cycle (i.e. clade selection). The extens...
Explaining cases of long-term persistence of parthenogenesis has proven an arduous task for evolutionary biologists. Interpreting sexual-asexual interactions though has recently advanced owing to methodological design, increased taxon sampling and choice of model organisms. We inferred the phylogeny of Artemia, a halophilic branchiopod genus of sexual and parthenogenetic forms with cosmopolitan...
Reproduction systems are controlling the creation of new genetic variants as well as how natural selection can operate on these variants. Therefore, they had historically been one of the main foci of evolutionary biology studies. The little fire ant, Wasmannia auropunctata, has been found to display an extraordinary reproduction system, in which both males and female queens are produced clonall...
Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to partheno...
For studying meiosis in males, large samples of Cacopsylla myrtilli (Wagner, 1947) (Hemiptera, Psyllidae) were collected in Norway, Sweden, Finland and northwest Russia. In addition to all-female populations, males were present in 10 out of 47 populations; still, all populations were highly female-biased, the proportion of males varying from 0.1% to 9.1%. These males are thus rare or so-called ...
BACKGROUND The tomato leafminer, Tuta absoluta is a damaging pest of crops worldwide. In the UK T. controlled using an integrated management (IPM) strategy that includes pheromone-based mating disruption. However, some growers have reported loss efficacy this technology, and there are concerns may evolve resistance via changes in its capacity to reproduce asexually. study we investigated reprod...
Parthenogenetic activation of human oocytes obtained from infertility treatments has gained new interest in recent years as an alternative approach to create embryos with no reproductive purpose for research in areas such as assisted reproduction technologies itself, somatic cell, and nuclear transfer experiments and for derivation of clinical grade pluripotent embryonic stem cells for regenera...
Female parthenogenesis, or thelytoky, is particularly common in solitary Hymenoptera. Only more recently has it become clear that many eusocial species also regularly reproduce thelytokously, and here we provide a comprehensive overview. Especially in ants, thelytoky underlies a variety of idiosyncratic life histories with unique evolutionary and ecological consequences. In all eusocial species...
Some reproductive parameters of adult stages of Amblyomma cajennense ticks were studied. The capacity of virgin females to reproduce by parthenogenesis was evaluated, during an experimental infestation, in absence of males, on a horse (Equus cabalus). Ticks were spread either completely free or in limited sites on the body of the animal. The engorged virgin females showed longer feeding periods...
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