Search results for "experimental"

Application of a new protocol to evaluate the benthic impacts of aquaculture: Colonization of experimental units for monitoring by polychaeta

2019

A range of different protocols and indices have been developed in recent years for the definition of Environmental Quality Standards in aquaculture. However, it can be difficult to compare these protocols or indices between different regions or different habitats due to spatial heterogeneity at different scales. We carried out a field study to estimate the effectiveness of experimental units (sediment-filled trays) as an environmental management tool. The experimental units were filled with two different sediments - sand and mud - and placed underneath two fish farm facilities for one month. Using polychaetes to assess the ecological status, AMBI and multidimensional analysis showed clear r…

Male house mice that have evolved with sperm competition have increased mating duration and paternity success

2013

Sperm competition imposes strong selection on males to gain fertilizations and maximize paternity. Males have been shown to adapt to sperm competition by modifying their behaviour and/or reproductive physiology. We investigated the fitness effects of male responses to sperm competition in house mice, Mus domesticus. Males that had been evolving with (polygamy) and without (monogamy) sperm competition for 18 generations were subject to different frequencies of social encounters with conspecific males to generate a sperm competition ‘risk’ treatment and a ‘no risk’ treatment. After manipulation of their social environment for 15–22 days, males were forced to compete for fertilizations against…

2020

Abstract The filamentous fungus Neurospora crassa, a model microbial eukaryote, has a life cycle with many features that make it suitable for studying experimental evolution. However, it has lacked a general tool for estimating relative fitness of different strains in competition experiments. To remedy this need, we constructed N. crassa strains that contain a modified csr-1 locus and developed an assay for detecting the proportion of the marked strain using a post PCR high resolution melting assay. DNA extraction from spore samples can be performed on 96-well plates, followed by a PCR step, which allows many samples to be processed with ease. Furthermore, we suggest a Bayesian approach for…

Marked Neurospora crassa strains for competition experiments and Bayesian methods for fitness estimates

2019

AbstractThe filamentous fungusNeurospora crassa, a model microbial eukaryote, has a life cycle with many features that make it suitable for studying experimental evolution. However, it has lacked a general tool for estimating relative fitness of different strains in competition experiments. To remedy this need, we constructedN. crassastrains that contain a modifiedcsr-1locus and developed an assay for detecting the proportion of the marked strain using a post PCR high resolution melting assay. DNA extraction from spore samples can be performed on 96-well plates, followed by a PCR step, which allows many samples to be processed with ease. Furthermore, we suggest a Bayesian approach for estim…

Fishery-induced selection for slow somatic growth in European eel

2012

International audience; Both theoretical and experimental studies have shown that fishing mortality can induce adaptive responses in body growth rates of fishes in the opposite direction of natural selection. We compared body growth rates in European eel (Anguilla anguilla) from three Mediterranean stocks subject to different fishing pressure. Results are consistent with the hypotheses that i) fast-growing individuals are more likely to survive until sexual maturity than slow-growing ones under natural conditions (no fishing) and ii) fishing can select for slow-growing individuals by removing fast-growing ones. Although the possibility of human-induced evolution seems remote for a panmictic…

Grapes and vines of the Phoenicians: morphometric analyses of pips from modern varieties and Iron Age archaeological sites in the Western Mediterrane…

2021

The present study aims to contribute to the investigation of the role of Phoenicians in the spreading and trade of the grapevine through the morphometric analysis of grape pips. Waterlogged and charred samples were selected from three Iron Age sites in the Western Mediterranean: Motya (Sicily, Italy), Nuraghe S’Urachi (Sardinia, Italy) and Huelva (Andalusia, Spain). While only Motya is a Phoenician foundation, all three were nevertheless associated with Phoenician expansion and cultural interaction. Ten cultivars from the “Vivaio Federico Paulsen” in Marsala (western Sicily) were chosen as modern reference material. The key challenge was the comparison of archaeological pips preserved throu…

Adaptation of turnip mosaic potyvirus to a specific niche reduces its genetic and environmental robustness

2020

Robustness is the preservation of the phenotype in the face of genetic and environmental perturbations. It has been argued that robustness must be an essential fitness component of RNA viruses owed to their small and compacted genomes, high mutation rates and living in ever-changing environmental conditions. Given that genetic robustness might hamper possible beneficial mutations, it has been suggested that genetic robustness can only evolve as a side-effect of the evolution of robustness mechanisms specific to cope with environmental perturbations, a theory known as plastogenetic congruence. However, empirical evidences from different viral systems are contradictory. To test how adaptation…

Empirical evidence for fast temperature-dependent body size evolution in rotifers

2017

Organisms tend to decrease in size with increasing temperature by phenotypic plasticity (the temperature-size rule; ectotherms) and/or genetically (Bergmann’s rule; all organisms). In this study, the evolutionary response of body size to temperature was examined in the cyclically parthenogenetic rotifer Brachionus plicatilis. Our aim was to investigate whether this species, already known to decrease in size with increasing temperature by phenotypic plasticity, presents a similar pattern at the genetic level. We exposed a multiclonal mixture of B. plicatilis to experimental evolution at low and high temperature and monitored body size weekly. Within a month, we observed a smaller size at hig…

Effect of repeated exposure to Plasmodium relictum (lineage SGS1) on infection dynamics in domestic canaries.

2010

7 pages; International audience; Parasites are known to exert strong selection pressures on their hosts and, as such, favour the evolution of defence mechanisms. The negative impact of parasites on their host can have substantial consequences in terms of population persistence and the epidemiology of the infection. In natural populations, however, it is difficult to assess the cost of infection while controlling for other potentially confounding factors. For instance, individuals are repeatedly exposed to a variety of parasite strains, some of which can elicit immunological memory, further protecting the host from subsequent infections. Cost of infection is, therefore, expected to be partic…

Viral fitness determines the magnitude of transcriptomic and epigenomic reprograming of defense responses in plants

2020

Although epigenetic factors may influence the expression of defense genes in plants, their role in antiviral responses and the impact of viral adaptation and evolution in shaping these interactions are still poorly explored. We used two isolates of turnip mosaic potyvirus with varying degrees of adaptation to Arabidopsis thaliana to address these issues. One of the isolates was experimentally evolved in the plant and presented increased load and virulence relative to the ancestral isolate. The magnitude of the transcriptomic responses was larger for the evolved isolate and indicated a role of innate immunity systems triggered by molecular patterns and effectors in the infection process. Sev…