نتایج جستجو برای: parthenogenetic
تعداد نتایج: 1519 فیلتر نتایج به سال:
Stimuli associated with copulatory behavior are often needed to maximize reproductive output in internally fertilized sexual taxa. Although non-pseudogamous parthenogenetic females have no need for sperm, parthenogens descended from sexual ancestors may still require copulatory stimuli to reach their full reproductive potential. Retention of physiological dependence on copulation in parthenogen...
Darevskia rock lizards include both sexual and parthenogenetic species, mostly distributed in the heterogeneous and ecologically diverse Caucasus. The parthenogenetic species originated via directional hybridogenesis, with only some of the sexual species known to serve as parentals. However, it remains unclear when and where these events happened and how many parental lineages were involved. A ...
Data were collected on the down color of 1,386 parthenogenetic embryos and poults from eggs of 306 young virgin and older nonmated bronze turkey hens. Each hen involved was heterozygous (Cc) for alleles which affect feather pigmentation. Six hundred and sixty nine white and 717 colored parthenogenetic embryos and poults were observed, a 1:1 ratio. Subsequently, 89 of these 306 heterozygous bron...
Parthenogenesis, a natural form of asexual reproduction produced from unfertilized eggs, occurs in many insects in Hemiptera and Hymenoptera, but very rarely in Lepidoptera. The current study aimed to test the larval density dependent occurrence of parthenogenesis in potato tuber moth, Phthorimaea operculella (Zeller; Lepidoptera: Gelechiidae) under laboratory conditions. More than 10% of femal...
One explanation for the success of sexual reproduction is that sex increases the efficacy of natural selection. Recombination and segregation lead to fitness variance among offspring which then offers a wider target for natural selection. Consequently, adaptation to changing environments is accelerated and population mean fitness will increase. We investigated whether low levels of sex are asso...
http://dx.doi.org/10.1016/j.anbehav.2014.12.017 0003-3472/© 2014 The Association for the Study of A Parthenogenesis is an asexual mode of reproduction that is rare in nature compared to sex. Parthenogenetic animals are derived from sexual progenitors, but little is known about how transitions to parthenogenesis evolve and persist. One hypothesis is that selection promotes transitions to parthen...
Of 40 Drosophila species screened to date, a majority have shown some ability to at least initiate parthenogenetic development. In one case, Drosophila mangebeirai, natural populations are entirely female, making it the only obligate parthenogenetic species of Drosophila Only a few of the species that exhibit the ability to undergo early embryonic development of unfertilized eggs successfully r...
Genetic and sexual systems can be evolutionarily dynamic within and among clades. However, identifying the processes responsible for switches between, for instance, sexual and asexual reproduction, or cyclic and non-cyclic life histories remains challenging. When animals evolve parthenogenetic reproduction, information about the sexual mating system becomes lost. Here we report an extraordinary...
Parthenogenesis is a relatively rare reproductive mode in nature compared to sex. In social insects, the evolution of parthenogenesis has a notable impact on their life histories. Some termites with parthenogenetic ability produce numerous non-dispersing supplementary queens asexually, whereas other castes are produced via sexual reproduction. This asexual queen succession (AQS) system is adapt...
Mammalian parthenogenesis could not survive but aborted during mid-gestation, presumably because of lack of paternal gene expression. To understand the molecular mechanisms underlying the failure of parthenogenesis at early stages of development, we performed global gene expression profiling and functional analysis of parthenogenetic blastocysts in comparison with those of blastocysts from norm...
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