asexuality

Reproduction and dispersal are key aspects of species life history that influence spatial genetic structure in populations. Several ant species in the genus Cataglyphis have evolved a unique breeding system in which new reproductives (that is, queens and males) are produced asexually by parthenogenesis; in contrast, non-reproductives (that is, workers) are produced via sexual reproduction by mates from distinct genetic lineages. We investigated how these two coexisting reproductive methods affect population-level spatial genetic structure using the ant Cataglyphis mauritanica as a model...

There is good reason to believe that the attitudes of persons without disability towards dating a person with a physical disability might be unfavourable. However, in general, and in the Global South in particular, there is a dearth of research in this area. This study sought to take the first step in addressing this lack of enquiry, by surveying the attitudes of a general population sample in South Africa towards dating people with physical disabilities, using a vignette. Data from 1723 survey respondents were analysed thematically...

Background and Aims: Paper mulberry or Broussonetia papyrifera (L.) L'Hér. ex Vent. (Moraceae) is a dioecious species native to continental South-east Asia and East Asia, including Taiwan, that was introduced to the Pacific by pre-historic voyagers and transported intentionally and propagated asexually across the full range of Austronesian expansion from Taiwan to East Polynesia. The aim of this study was to gain insight into the dispersal of paper mulberry into Oceania through the genetic analysis of herbaria samples which represent a more complete coverage of the historical geographical range of the species in the Pacific before later introductions and local extinctions occurred...

Images of sexually active women beyond the age of 50 are lacking in popular culture and in particular on television. Dominant sexual scripts depict older women as generally asexual. The television program Hot in Cleveland features unpartnered midlife and older women as main characters. In this article, based on analysis of four seasons of Hot in Cleveland, we look closely at portrayals of sexual activity to see whether they underscore dominant sexual scripts mocking older women's sexual interest, position aging as sexual decline, or reinforce the narrative of "successful" aging/aging as progress...

Bending of 2D cell sheets is a fundamental morphogenetic mechanism during animal development and reproduction. A critical player driving cell shape during tissue bending is the actin cytoskeleton. Much of our current knowledge about actin dynamics in whole organisms stems from studies of embryonic development in bilaterian model organisms. Here, we have analysed actin-based processes during asexual bud evagination in the simple metazoan Hydra We created transgenic Hydra strains stably expressing the actin marker Lifeact-GFP in either ectodermal or endodermal epitheliomuscular cells...

Research has shown that a change in environmental conditions can alter the expression of traits during development (i.e., 'within-generation phenotypic plasticity') as well as induce heritable phenotypic responses that persist for multiple generations (i.e., 'transgenerational plasticity'). It has long been assumed that shifts in gene expression are tightly linked to observed trait responses at the phenotypic level. Yet, the manner in which organisms couple within- and trans-generational plasticity at the molecular level is unclear...

During a survey of saprophytic microfungi on decomposing woody, herbaceous debris and soil from different regions in Southern Europe, a wide range of interesting species of asexual ascomycetes were found. Phylogenetic analyses based on partial gene sequences of SSU, LSU and ITS proved that most of these fungi were related to Sordariomycetes and Dothideomycetes and to lesser extent to Leotiomycetes and Eurotiomycetes. Four new monotypic orders with their respective families are proposed here, i.e. Lauriomycetales, Lauriomycetaceae; Parasympodiellales, Parasympodiellaceae; Vermiculariopsiellales, Vermiculariopsiellaceae and Xenospadicoidales, Xenospadicoidaceae...

Insect management strategies for agricultural crop pests must reduce selection for insecticide resistant mutants while providing effective control of the insect pest. One management strategy that has long been advocated is the application of insecticides at the maximum permitted dose. This has been found, under some circumstances, to be able to prevent the resistance allele frequency from increasing. However this approach may, under different circumstances, lead to rapid selection for resistance to the insecticide...

Polyps of two moon jellyfish species, Aurelia coerulea and A. relicta, from two Adriatic Sea coastal habitats were incubated under multiple combinations of temperature (14, 21°C), salinity (24, 37 ppt) and food regime (9.3, 18.6, 27.9 μg C ind-1 week-1) to comparatively assess how these factors may influence major asexual reproduction processes in the two species. Both species exhibited a shared pattern of budding mode (Directly Budded Polyps: DBP; Stolonal Budded Polyps: SBP), with DBP favoured under low food supply (9...

BACKGROUND: Aspartate, which is converted from oxaloacetate (OAA) by aspartate aminotransferase, is considered an important precursor for purine salvage and pyrimidine de novo biosynthesis, and is thus indispensable for the growth of Plasmodium parasites at the asexual blood stages. OAA can be produced in malaria parasites via two routes: (i) from phosphoenolpyruvate (PEP) by phosphoenolpyruvate carboxylase (PEPC) in the cytosol, or (ii) from fumarate by consecutive reactions catalyzed by fumarate hydratase (FH) and malate:quinone oxidoreductase (MQO) in the mitochondria of malaria parasites...

A new species, Scopulariopsis gossypii, was found to be present in the vascular bundles of cotton plants (Gossypium hirsutum) infected by Verticillium dahliae which is an economically important pathogen in Hangzhou, China. The fungus was only present in the diseased plants, but it never became isolated from the healthy plants. Scanning electron microscopy showed that the fungus was present in parenchyma cells enclosing vessels in dark brown vascular tissues of stems, and produced asexual conidia within the tissues...

Benjaminiella poitrasii, a dimorphic non-pathogenic zygomycetous fungus, exhibits a morphological yeast (Y) to hypha (H) reversible transition in the vegetative phase, sporangiospores (S) in the asexual phase and zygospores (Z) in the sexual phase. To study the gene expression across these diverse morphological forms, suitable reference genes are required. In the present study, 13 genes viz. ACT, 18S rRNA, eEF1α, eEF-Tu,eIF-1A, Tub-α, Tub-b, Ubc, GAPDH, Try, WS-21, NADGDH and NADPGDH were evaluated for their potential as a reference, particularly for studying gene expression during the Y-H reversible transition and also for other asexual and sexual life stages of B...

Approximately 20% of species in the fungal kingdom are only known to reproduce by asexual means despite the many supposed advantages of sexual reproduction. However, in recent years, sexual cycles have been induced in a series of emblematic "asexual" species. We describe how these discoveries were made, building on observations of evidence for sexual potential or "cryptic sexuality" from population genetic analyses; the presence, distribution, and functionality of mating-type genes; genome analyses revealing the presence of genes linked to sexuality; the functionality of sex-related genes; and formation of sex-related developmental structures...

Root-knot nematodes (genus Meloidogyne) exhibit a diversity of reproductive modes ranging from obligatory sexual to fully asexual reproduction. Intriguingly, the most widespread and devastating species to global agriculture are those that reproduce asexually, without meiosis. To disentangle this surprising parasitic success despite the absence of sex and genetic exchanges, we have sequenced and assembled the genomes of three obligatory ameiotic and asexual Meloidogyne. We have compared them to those of relatives able to perform meiosis and sexual reproduction...

Scyphozoa, Cubozoa and Hydrozoa are classes in the phylum Cnidaria that undergo metagenesis involving a dramatic morphological transition. In Scyphozoa and Cubozoa, when exposed to species- or strain-specific transition-inducing stimuli, asexually reproducing benthic polyps transform into sexually reproducing planktonic medusae. In Hydrozoa, exposure to species- or strainspecific transition-inducing stimuli causes formation of medusa buds in the polyp's body. In Aurelia aurita (Linnaeus, 1758) (Scyphozoa, Semaeostomeae), polyp-to-jellyfish transition is induced by some simple indole compounds...

BACKGROUND: Malaria remains a major health hazard in the modern world, particularly in developing countries. In Plasmodium falciparum malaria, there is a direct correlation between asexual erythrocytic stage parasite density and disease severity. Accordingly, the correlations between parasite density and various clinical presentations, severity, and outcome were examined in falciparum malaria in India. MATERIALS AND METHODS: The study was conducted in a tertiary health-care center in North India...

Background and aims: Onset of reproduction and reproductive allocation patterns are key components of plant reproductive strategies. Life history theory predicts that plants in adverse environments for juvenile performance start reproduction at smaller sizes and exhibit higher reproductive allocation compared to their counterparts in favourable environments. Life history theory will gain in generality if its predictions are shown to apply to a broad range of organisms and modes of reproduction...

Two-component signal transduction (TCST) pathways play crucial roles in many cellular functions such as stress responses, biofilm formation, and sporulation. The histidine phosphotransferase (HPt), which is an intermediate phosphotransfer protein in a two-component system, transfers a phosphate group to a phosphorylatable aspartate residue in the target protein(s), and up-regulates stress-activated MAP kinase cascades. Most fungal genomes carry a single copy of the gene coding for HPt, which are potential antifungal targets...

The somatic mobilization of transposable elements is more common than previously thought. In this review we discuss how the intensity and the biologic consequences of somatic mobilization are dependent on the transposable elements landscapes of each genome, and on the "momentum" of each particular TE with respect to the mechanisms that control its transposition and the possibility to escape this control. Additionally, the biologic consequences of somatic mobilization vary among organisms that show an early separation between the germline and somatic cells and those organisms that do not exhibit this separation or that reproduce asexually...

BACKGROUND: We investigated the prevalence of sub-microscopic Plasmodium falciparum infections and gametocyte carriage in asymptomatic individuals in Navrongo in northern Ghana, an area of seasonal malaria transmission. DESIGN: A cross sectional study of 209 randomly selected participants of all age-groups was conducted in February and March, 2015. METHODS: Capillary blood samples collected from these individuals were used for the detection of both asexual and gametocyte stage parasites by microscopy, reverse transcriptase polymerase chain reaction (RT-PCR) and conventional nested PCR methods...