Search results for " Variation"
showing 10 items of 1712 documents
Synchronous attack is advantageous: mixed genotype infections lead to higher infection success in trematode parasites
2011
Co-infecting parasite genotypes typically compete for host resources limiting their fitness. The intensity of such competition depends on whether parasites are reproducing in a host, or using it primarily as a transmission vehicle while not multiplying in host tissues (referred to as ‘competition hypothesis’). Alternatively, simultaneous attack and co-infection by several parasite genotypes might facilitate parasite infection because such a diverse attack could present an additional challenge to host immune defence (referred to as ‘facilitation hypothesis’). We tested the competition hypothesis by comparing the production of transmission stages (cercariae) from snails infected with one or …
The genome sequencing of an albino Western lowland gorilla reveals inbreeding in the wild
2013
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.
Effects of temperature on total phenolic compounds in Cystoseira amentacea (C. Agardh) Bory (Fucales, Phaeophyceae) from southern Mediterranean Sea
2015
The aim of this study was to test the effects of temperature on phenolic content of the brown seaweed Cystoseira amentacea. Phenolic compounds are secondary metabolites involved in different protection mechanisms as, for example, against grazers, epiphytes and UV radiation. Seasonal variations of phenolic content in C. amentacea were analysed and laboratory experiments, in which C. amentacea was exposed to an increase of temperature (25°C and 30°C), were performed. Total phenolic content (TPC) was determined colorimetrically with the Folin–Ciocalteu reagent. In C. amentacea, a seasonal pattern in TPC was observed, with a maximum value in winter-spring. C. amentacea responded significantly t…
Nested core collections maximizing genetic diversity in Arabidopsis thaliana.
2004
Summary The successful exploitation of natural genetic diversity requires a basic knowledge of the extent of the variation present in a species. To study natural variation in Arabidopsis thaliana, we defined nested core collections maximizing the diversity present among a worldwide set of 265 accessions. The core collections were generated based on DNA sequence data from a limited number of fragments evenly distributed in the genome and were shown to successfully capture the molecular diversity in other loci as well as the morphological diversity. The core collections are available to the scientific community and thus provide an important resource for the study of genetic variation and its …
Degradation of sexual reproduction in Veronica filiformis after introduction to Europe
2011
Abstract Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual rep…
Does beak coloration of male blackbirds play a role in intra and/or intersexual selection?
2002
In many bird species, males may show brightly coloured traits and variance in male mating success may be explained by female preference and/or competition between males favouring the most coloured males. Male beak coloration has been suggested to play an important role in the pairing pattern of European blackbirds. Here, we investigate female preference and male-male interactions in relation to male beak coloration in this species. We used a field experiment to measure female and male responses toward stuffed decoys showing either of two beak coloration representing the extremes of the natural variation from yellow to orange. Decoys were situated on the centre of plots and behaviours of mal…
Genetic and phenotypic variation of the malaria vector Anopheles atroparvus in southern Europe
2011
Abstract Background There is a growing concern that global climate change will affect the potential for pathogen transmission by insect species that are vectors of human diseases. One of these species is the former European malaria vector, Anopheles atroparvus. Levels of population differentiation of An. atroparvus from southern Europe were characterized as a first attempt to elucidate patterns of population structure of this former malaria vector. Results are discussed in light of a hypothetical situation of re-establishment of malaria transmission. Methods Genetic and phenotypic variation was analysed in nine mosquito samples collected from five European countries, using eight microsatell…
Evidence of a highly complex phylogeographic structure on a specialist river bird species, the dipper (Cinclus cinclus)
2008
This study details the phylogeographic pattern of the white-throated dipper (Cinclus cinclus), a Palearctic, temperate, passerine bird that is exclusively associated with flowing water. Our results reveal a complex phylogeographic structure with at least five distinct lineages for the Western Palearctic region. As for many species of the Western Palearctic fauna and flora, this genetic structure is probably linked to the isolation of populations in different southern refuges during glacial periods. Furthermore, the isolation of populations in Scandinavia and/or Eastern regions, but also in Morocco and probably in Corsica, was accentuated by ecological and biogeographic barriers during Quate…
Coping styles in farmed fish: consequences for aquaculture
2017
Individual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies have demonstrated links to performance traits, health and disease susceptibility and welfare. This study will review (i) the main behavioural, neuroendocrine, cognitive and emotional differences between …
FOOD MAKES YOU A TARGET: DISENTANGLING GENETIC, PHYSIOLOGICAL, AND BEHAVIORAL EFFECTS DETERMINING SUSCEPTIBILITY TO INFECTION
2010
Genetics, physiology, and behavior are all expected to influence the susceptibility of hosts to parasites. Furthermore, interactions between genetic and other factors are suggested to contribute to the maintenance of genetic polymorphism in resistance when the relative susceptibility of host genotypes is context dependent. We used a maternal sibship design and long- and short-term food deprivation treatments to test the role of family-level genetic variation, body condition, physiological state, and foraging behavior on the susceptibility of Lymnaea stagnalis snails to infection by a trematode parasite that uses chemical cues to locate its hosts. In experimental exposures, we found that sna…