Search results for "Biological Evolution"
showing 10 items of 522 documents
Back to the roots: the importance of using simple insect societies to understand the molecular basis of complex social life
2018
The evolutionary trajectories toward insect eusociality come in two broad forms. In species like wasps, bees, and ants, the first helpers remained at the nest primarily to help with brood care. In species like aphids and termites, on the other hand, nest defense was initially the primary ecological driving force. To better understand the molecular basis of these two alternative evolutionary trajectories, it is therefore important to study the mechanistic basis of brood care and nest defense behavior. So far, most studies have compared morphologically distinct castes in advanced eusocial species of ants, bees, wasps, and termites. However, the interpretation of such comparisons is limited by…
Transgenerational effects of insecticides - implications for rapid pest evolution in agroecosystems
2018
Although pesticides are a major selective force in driving the evolution of insect pests, the evolutionary processes that give rise to insecticide resistance remain poorly understood. Insecticide resistance has been widely observed to increase with frequent and intense insecticide exposure, but can be lost following the relaxation of insecticide use. One possible but rarely explored explanation is that insecticide resistance may be associated with epigenetic modifications, which influence the patterning of gene expression without changing underlying DNA sequence. Epigenetic modifications such as DNA methylation, histone modifications, and small RNAs have been observed to be heritable in art…
Molecular characterisation, evolution and expression analysis of g-type lysozymes in Ciona intestinalis
2017
Lysozyme is an important defense molecule of the innate immune system. Known for its bactericidal properties, lysozyme catalyzes the hydrolysis of b-(1,4)-glycosidic bonds between the N-acetyl glucosamine and N-acetyl muramic acid in the peptidoglycan layer of bacterial cell walls. In this study, the complete coding sequence of four g-type lysozymes were identified in Ciona intestinalis. Phylogenetic analysis and modelling supported the hypothesis of a close relationship with the vertebrate g-type lysozymes suggesting that the C. intestinalis g-type lysozyme genes (CiLys-g1, Cilys-g2, CiLys-g3, CiLys-g4) share a common ancestor in the chordate lineage. Protein motif searches indicated that …
Unexpected diversity in socially synchronized rhythms of shorebirds.
2016
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1,2,3,4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1,5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6,7,8,9,10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6,7,8,9,11. The behavioural rhythms that em…
The evolution of the Cercopithecini: a (post)modern synthesis.
2017
The Cercopithecini, or African guenon monkeys, are one of the most diverse clades of living primates and comprise the most species-rich clade of Catarrhini. Species identity is announced by flamboyant coloration of the facial and genital regions and, more cryptically, by vigorous chromosomal rearrangements among taxa. Beneath the skin, however, these animals are skeletally conservative and show low levels of genetic sequence divergence consonant with recent divergence between congeneric species. The guenons clearly demonstrate that morphological, cytogenetic, and reproductive differentiation proceed at different rates during speciation. We review diverse kinds of data in an effort to unders…
Microevolution of bank voles (Myodes glareolus) at neutral and immune-related genes during multiannual dynamic cycles: consequences for Puumala hanta…
2017
ABSTRACTUnderstanding how host dynamics, including variations of population size and dispersal, may affect the epidemiology of infectious diseases through ecological and evolutionary processes is an active research area. Here we focus on a bank vole (Myodes glareolus) metapopulation surveyed in Finland between 2005 and 2009. Bank vole is the reservoir of Puumala hantavirus (PUUV), the agent of nephropathia epidemica (NE, a mild form of hemorrhagic fever with renal symptom) in humans.M glareoluspopulations experience multiannual density fluctuations that may influence the level of genetic diversity maintained in bank voles, PUUV prevalence and NE occurrence. We examine bank vole metapopulati…
Socio-Reproductive Conflicts and the Father’s Curse Dilemma
2018
Evolutionary conflicts between males and females can manifest over sexually antagonistic interactions at loci or over sexually antagonistic interests within a locus. The latter form of conflict, intralocus sexual conflict, arises from sexually antagonistic selection and constrains the fitness of individuals through a phenotypic compromise. These conflicts, and socio-reproductive interactions in general, are commonly mediated by hormones, and thus predictive insights can be gained from studying their mediating effects. Here, we integrate several lines of evidence to describe a novel, hormonally mediated reproductive dilemma that we call the father’s curse, which results from an intralocus co…
Trans-generational immune priming in the mealworm beetle protects eggs through pathogen-dependent mechanisms imposing no immediate fitness cost for t…
2018
8 pages; International audience; Immune-challenged mothers can improve their offspring immunity through trans-generational immune priming (TGIP). In insects, TGIP endows the offspring with lifetime immunity, including the eggs, which are likely exposed soon after maternal infection. Egg protection may rely on the transfer of maternal immune effectors to the egg or/and the induction of egg immune genes. These respective mechanisms are assumed to have early-life fitness costs of different magnitude for the offspring. We provide evidence in the mealworm beetle Tenebrio molitor that enhanced egg immunity following a maternal immune challenge is achieved by both of these mechanisms but in a path…
Aromatic and proteomic analyses corroborate the distinction between Mediterranean landraces and modern varieties of durum wheat
2016
AbstractIn this paper volatile organic compounds (VOCs) from durum wheat cultivars and landraces were analyzed using PTR-TOF-MS. The aim was to characterize the VOC’s profile of the wholemeal flour and of the kernel to find out if any VOCs were specific to varieties and sample matrices. The VOC data is accompanied by SDS-PAGE analyses of the storage proteins (gliadins and glutenins). Statistical analyses was carried out both on the signals obtained by MS and on the protein profiles. The difference between the VOC profile of two cultivars or two preparations of the same sample - matrices, in this case kernel vs wholemeal flour - can be very subtle; the high resolution of PTR-TOF-MS - down to…
One year into the pandemic: Short-term evolution of SARS-CoV-2 and emergence of new lineages.
2021
The COVID-19 pandemic was officially declared on March 11th, 2020. Since the very beginning, the spread of the virus has been tracked nearly in real-time by worldwide genome sequencing efforts. As of March 2021, more than 830,000 SARS-CoV-2 genomes have been uploaded in GISAID and this wealth of data allowed researchers to study the evolution of SARS-CoV-2 during this first pandemic year. In parallel, nomenclatures systems, often with poor consistency among each other, have been developed to designate emerging viral lineages. Despite general fears that the virus might mutate to become more virulent or transmissible, SARS-CoV-2 genetic diversity has remained relatively low during the first ~…