Search results for "Genetics"
showing 10 items of 12494 documents
The Search for Common Origin: Homology Revisited
2018
Understanding the evolution of biodiversity on Earth is a central aim in biology. Currently, various disciplines of science contribute to unravel evolution at all levels of life, from individual organisms to species and higher ranks, using different approaches and specific terminologies. The search for common origin, traditionally called homology, is a connecting paradigm of all studies related to evolution. However, it is not always sufficiently taken into account that defining homology depends on the hierarchical level studied (organism, population, and species), which can cause confusion. Therefore, we propose a framework to define homologies making use of existing terms, which refer to …
Ant behaviour and brain gene expression of defending hosts depend on the ecological success of the intruding social parasite.
2019
The geographical mosaic theory of coevolution predicts that species interactions vary between locales. Depending on who leads the coevolutionary arms race, the effectivity of parasite attack or host defence strategies will explain parasite prevalence. Here, we compare behaviour and brain transcriptomes of Temnothorax longispinosus ant workers when defending their nest against an invading social parasite, the slavemaking ant Temnothorax americanus . A full-factorial design allowed us to test whether behaviour and gene expression are linked to parasite pressure on host populations or to the ecological success of parasite populations. Albeit host defences had been shown before to covary with …
Demographic history has shaped the strongly differentiated corkwing wrasse populations in Northern Europe
2019
Understanding the biological processes involved in genetic differentiation and divergence between populations within species is a pivotal aim in evolutionary biology. One particular phenomenon that requires clarification is the maintenance of genetic barriers despite the high potential for gene flow in the marine environment. Such patterns have been attributed to limited dispersal or local adaptation, and to a lesser extent to the demographic history of the species. The corkwing wrasse (Symphodus melops) is an example of a marine fish species where regions of particular strong divergence are observed. One such genetic break occurred at a surprisingly small spatial scale (FST ~0.1), over a s…
The influence of slavemaking lifestyle, caste and sex on chemical profiles in Temnothorax ants: insights into the evolution of cuticular hydrocarbons
2017
Chemical communication is central for the formation and maintenance of insect societies. Generally, social insects only allow nest-mates into their colony, which are recognized by their cuticular hydrocarbons (CHCs). Social parasites, which exploit insect societies, are selected to circumvent host recognition. Here, we studied whether chemical strategies to reduce recognition evolved convergently in slavemaking ants, and whether they extend to workers, queens and males alike. We studied CHCs of three social parasites and their related hosts to investigate whether the parasitic lifestyle selects for specific chemical traits that reduce host recognition. Slavemaker profiles were characterize…
Local adaptation of plant viruses: lessons from experimental evolution.
2016
[EN] For multihost pathogens, adaptation to multiple hosts has important implications for both applied and basic research. At the applied level, it is one of the main factors determining the probability and severity of emerging disease outbreaks. At the basic level, it is thought to be a key mechanism for the maintenance of genetic diversity both in host and pathogen species. In recent years, a number of evolution experiments have assessed the fate of plant virus populations replicating within and adapting to one single or to multiple hosts species. A first group of these experiments tackled the existence of trade-offs in fitness and virulence for viruses evolving either within a single hos…
The legacy of a vanished sea: a high level of diversification within a European freshwater amphipod species complex driven by 15 My of Paratethys reg…
2016
16 pages; International audience; The formation of continental Europe in the Neogene was due to the regression of the Tethys Ocean and of the Paratethys Sea. The dynamic geology of the area and repetitious transitions between marine and freshwater conditions presented opportunities for the colonization of newly emerging hydrological networks and diversification of aquatic biota. Implementing mitochondrial and nuclear markers in conjunction with a large-scale sampling strategy, we investigated the impact of this spatiotemporal framework on the evolutionary history of a freshwater crustacean morphospecies. The Gammarus balcanicus species complex is widely distributed in the area previously oc…
Assessment of genetic diversity and relatedness in the Latvian potato genetic resources collection by DArT genotyping
2015
Potato (Solanum tuberosumL.) has been cultivated in Latvia since the 17th century, and formal breeding programmes have been established since the start of the 20th century. The Latvian potato genetic resource collection consists of 83 accessions of Latvian origin, including landraces, old cultivars released starting from the 1930's, modern cultivars and breeding material. These are maintained in field andin vitrocollections. Pedigree information about the potato cultivars is often limited, and the use of hybrids of local cultivars as parents is common in the Latvian potato breeding programme. Ninety-four Latvian potato varieties and breeding lines and some commonly used foreign accessions w…
Lipid Nanoparticles as Potential Gene Therapeutic Delivery Systems for Oral Administration.
2017
Background Gene therapy has experimented an increasing attention in the last decades, due to its enormous potential applications in the medical field. It can be defined as the use of genes or genetic material (DNA, RNA, oligonucleotides) to treat or prevent a disease state, generally a geneticbased one. Application Other applications, like treating viral, bacterial or parasite infections or development of vaccines are gaining also interest. Efficient gene therapy is mainly dependent on the ability of the highly labile genetic material to reach the therapeutic target. For this purpose, different delivery systems have been designed and extensively investigated. Nanoparticles offer a broad ran…
EVOLUTIONARY DYNAMICS OF FITNESS RECOVERY FROM THE DEBILITATING EFFECTS OF MULLER'S RATCHET.
1998
The great adaptability shown by RNA viruses is a consequence of their high mutation rates. The evolution of fitness in a severely debilitated, clonal population of the nonsegmented ribovirus vesicular stomatitis virus (VSV) has been compared under five different demographic regimes, ranging from severe serial bottleneck passages (one virion) to large population passages (105 virions or more) under similar environmental conditions (cell culture type and temperature). No matter how small the bottleneck, the fitness of the evolved populations was always higher than the fitness of the starting population; this result is clearly different from that previously reported for viruses with higher fit…
Selective sweep ofWolbachiaand parthenogenetic host genomes - the example of the weevilEusomus ovulum
2016
Most parthenogenetic weevil species are postulated to have originated via hybridization, but Wolbachia has also been speculated to play a role via the induction of parthenogenesis. Here, we examine the molecular diversity of Wolbachia and parthenogenetic host genomes. The host species studied here, Eusomus ovulum, is known to be exclusively parthenogenetic and triploid. The E. ovulum populations that we examined had a low genetic diversity of mitochondrial (cytochrome oxidase I gene) and nuclear markers (internal transcribed spacer 2 and elongation factor 1-α gene), and they all were infected by only single bacteria strains (genotyped for five genes according to the multilocus sequence typi…