| new species of gyrodactylus and dactylogyrus (trematoda: monogenea) from fishes of nebraska. | six new monogenetic trematodes are described from nebraska fishes: gyrodactylus bulbacanthus sp. n. from fundulus kansae (garman); g. callawayensis sp. n. from notropis lutrensis (baird and girard); g. eos sp. n. from phoxinus eos (cope); g. nebraskensis from phoxinus neogaeus (cope); g. planensis from notropis dorsalis (agassiz); and dactylogyrus pectenatus from pimephales promelas (rafinesque). this is the second report of monogeneans from nebraska fishes. | 1977 | 915609 |
| potential impacts of clearcutting on parasites of minnows in small boreal lakes. | clearcutting and deforestation lead to increased erosion, increased water temperature, altered water chemistry, and modified watershed hydrology in aquatic systems. effects on biological organisms have been documented for phytoplankton, zooplankton, benthos, and fish. in this study, parasites of the northern redbelly dace, phoxinus eos (cope), were examined from an experimental area consisting of headwater lakes and their watersheds in the boreal forest of ontario, canada prior to and after clea ... | 2001 | 11817450 |
| permanent genetic resources added to molecular ecology resources database 1 january 2009-30 april 2009. | this article documents the addition of 283 microsatellite marker loci to the molecular ecology resources database. loci were developed for the following species: agalinis acuta; ambrosia artemisiifolia; berula erecta; casuarius casuarius; cercospora zeae-maydis; chorthippus parallelus; conyza canadensis; cotesia sesamiae; epinephelus acanthistius; ficedula hypoleuca; grindelia hirsutula; guadua angustifolia; leucadendron rubrum; maritrema novaezealandensis; meretrix meretrix; nilaparvata lugens; ... | 2009 | 21564911 |
| gyrodactylus laevisoides n. sp. (monogenea: gyrodactylidae) infecting northern redbelly dace phoxinus eos cope (cyprinidae) from nova scotia, canada. | gyrodactylus laevisoides n. sp. is described from the gill rakers of red belly dace, phoxinus eos cope (cyprinidae), from nova scotia, canada. gyrodactylus laevisoides n. sp. is the second species of gyrodactylus nordmann, 1832 described from this host and is characterised by weakly curving hamuli, a small ventral bar lacking anterolateral processes, stout dorsal bar, small marginal hooks with sickles larger proximally than distally and having a small circular process on the heel, a mco with spi ... | 2013 | 24163028 |
| coordination of cytochrome c oxidase gene expression in the remodelling of skeletal muscle. | many fish species respond to low temperature by inducing mitochondrial biogenesis, reflected in an increase in activity of the mitochondrial enzyme cytochrome c oxidase (cox). cox is composed of 13 subunits, three encoded by mitochondrial (mt)dna and 10 encoded by nuclear genes. we used real-time pcr to measure mrna levels for the 10 nuclear-encoded genes that are highly expressed in muscle. we measured mrna levels in white muscle of three minnow species, each at two temperatures: zebrafish (dan ... | 2011 | 21562175 |
| asymmetry in dentition and shape of pharyngeal arches in the clonal fish chrosomus eos-neogaeus: phenotypic plasticity and developmental instability. | the effect of the environment may result in different developmental outcomes. extrinsic signals can modify developmental pathways and result in alternative phenotypes (phenotypic plasticity). the environment can also be interpreted as a stressor and increase developmental instability (developmental noise). directional and fluctuating asymmetry provide a conceptual background to discriminate between these results. this study aims at assessing whether variation in dentition and shape of pharyngeal ... | 2017 | 28380079 |
| inconsistent phylogeographic pattern between a sperm dependent fish and its host: in situ hybridization vs dispersal. | co-dispersal of sperm-dependent hybrids and their sexual relatives is expected to result in consistent spatial patterns between assemblages of hybrids and genetic structure of parental species. however, local hybridization events may blur this signal as assemblages could be organized under different connectivity constraints. this study aims at testing the hypothesis of local hybridization events by comparing the assemblage of hybrid fish chrosomus eos-neogaeus to the genetic diversity of one of ... | 2016 | 27600616 |
| facing environmental predictability with different sources of epigenetic variation. | different sources of epigenetic changes can increase the range of phenotypic options. environmentally induced epigenetic changes and stochastic epimutations are, respectively, associated with phenotypic plasticity and diversifying bet-hedging. their relative contribution is thus expected to reflect the capacity of a genotype to face distinct changes since these strategies are differentially selected according to environmental uncertainty. to test this hypothesis, we assessed the sources of epige ... | 2016 | 27551379 |
| analysis of potential factors allowing coexistence in a sexual/asexual minnow complex. | the northern redbelly dace (chrosomus eos) and the finescale dace (c. neogaeus) have hybridized to produce an all-female, asexual hybrid (c. eos-neogaeus) that reproduces by sperm-limited parthenogenesis (gynogenesis). however, in this system, gynogenesis is not 100 % efficient; triploid females are occasionally formed which reproduce as sexuals, producing nuclear males and females of the paternal species (generally c. eos). thus, the asexual lineage continually produces occasional males that ca ... | 2016 | 26650583 |
| interactions between nuclear genes and a foreign mitochondrial genome in the redbelly dace chrosomus eos. | given the coevolution process occurring between nuclear and mitochondrial genomes, the effects of introgressive hybridization remain puzzling. in this study, we take advantage of the natural co-occurrence of two biotypes bearing a similar nuclear genome (chrosomus eos) but harbouring mitochondria from different species (wild type: c. eos; cybrids: chrosomus neogaeus) to determine the extent of phenotype changes linked to divergence in the mitochondrial genome. changes were assessed through diffe ... | 2015 | 26277640 |
| the key role of epigenetics in the persistence of asexual lineages. | asexual organisms, often perceived as evolutionary dead ends, can be long-lived and geographically widespread. we propose that epigenetic mechanisms could play a crucial role in the evolutionary persistence of these lineages. genetically identical organisms could rely on phenotypic plasticity to face environmental variation. epigenetic modifications could be the molecular mechanism enabling such phenotypic plasticity; they can be influenced by the environment and act at shorter timescales than m ... | 2012 | 22567390 |
| general-purpose genotype or how epigenetics extend the flexibility of a genotype. | this project aims at investigating the link between individual epigenetic variability (not related to genetic variability) and the variation of natural environmental conditions. we studied dna methylation polymorphisms of individuals belonging to a single genetic lineage of the clonal diploid fish chrosomus eos-neogaeus sampled in seven geographically distant lakes. in spite of a low number of informative fragments obtained from an msap analysis, individuals of a given lake are epigenetically si ... | 2012 | 22567383 |
| behavioural responses of prey fishes to habitat complexity and predation risk induce bias in minnow trap catches. | the effects of predation risk and habitat complexity on the efficiency of minnow traps to catch northern redbelly dace chrosomus eos in laboratory experiments were investigated. trap efficiency significantly decreased in the presence of vegetation and predators. these results suggest that the various antipredator behaviours used by prey fishes can affect trap efficiency. | 2011 | 21781108 |
| repeat swimming performance and its implications for inferring the relative fitness of asexual hybrid dace (pisces: phoxinus) and their sexually reproducing parental species. | while theories explaining the evolution and maintenance of sex are abundant, empirical data on the costs and benefits of asexual relative to sexual reproduction are less common. asexually reproducing vertebrates, while few, provide a rare opportunity to measure differences in fitness between asexual and sexual species. all known asexually reproducing vertebrates are of hybrid origin, and hybrid disadvantage (i.e., reduced hybrid fitness) is thought to facilitate long-term coexistence between ase ... | 2011 | 21527822 |
| dna methylation: a source of random variation in natural populations. | epigenetic processes (e.g., dna methylation) have been proposed as potentially important evolutionary mechanisms. however, before drawing conclusions about their evolutionary relevance, we need to evaluate the independence of epigenetic variation from genetic variation, as well as the extent of methylation polymorphism in nature. we evaluated these in natural populations of a clonal fish, chrosomus eos-neogaeus, for which genetically identical individuals may be found in distinct environments. a ... | 2011 | 21266851 |
| distribution of phoxinus eos, phoxinus neogaeus, and their asexually-reproducing hybrids (pisces: cyprinidae) in algonquin provincial park, ontario. | hybrid phoxinus are one of the few asexually reproducing vertebrates species. the distribution of hybrid phoxinus among lakes in algonquin park, ontario, was evaluated relative to the distribution of parental species and relative to physiochemical lake characteristics. no association between the distribution of hybrids and the distribution of parental species was found, suggesting that the hybrids can successfully coexist with either parental species. in addition, we found no association between ... | 2010 | 20957232 |
| does predation risk influence habitat use by northern redbelly dace phoxinus eos at different spatial scales? | this study investigated the relationship between spatial variations in predation risk and abundance of northern redbelly dace phoxinus eos at both macroscale (littoral v. pelagic zones) and microscale (structured v. open water habitats in the littoral zone) of canadian shield lakes. minnow traps were placed in both structured and open water habitats in the littoral zone of 13 canadian shield lakes, and estimates of the relative predation risk of p. eos in both the pelagic and the littoral zones ... | 2009 | 20735640 |
| the origin of phoxinus eos-neogaeus unisexual hybrids. | phoxinus eos-neogaeus unisexual hybrids (cyprinidae, pisces) are among the few vertebrate taxa known to reproduce clonally by gynogenesis. these taxa have a broad distribution in north america, mostly located in regions previously covered by the last pleistocene ice sheet. to assess whether asexual hybrids dispersed from glacial refuges at the end of the pleistocene or they originated from current hybridization events, genetic diversity of mitochondrial dna (mtdna) sequences and microsatellite l ... | 2007 | 17892466 |
| phenotypic consequences of genetic variation in a gynogenetic complex of phoxinus eos-neogaeus clonal fish (pisces: cyprinidae) inhabiting a heterogeneous environment. | we examined the genetic composition, habitat use, and morphological variation of a phoxinus eos-neogaeus unisexual hybrid complex and its sexually reproducing progenitor species inhabiting beaver-modified drainages of voyageurs national park, minnesota. in addition to the single diploid p. eos-neogaeus gynogenetic clone, triploid and diploid-triploid mosaic biotypes were present at our study sites. both p. eos and p. neogaeus, and all three hybrid biotypes were ubiquitous throughout one intensiv ... | 2004 | 15266975 |
| unexpected ratio of allozyme expression in diploid and triploid individuals of the clonal hybrid fish phoxinus eos-neogaeus. | phoxinus eos-neogaeus, a north american freshwater fish, was formed by hybridization between p. neogaeus and p. eos. individuals of p. eos-neogaeus express one allozyme of p. eos and one allozyme of p. neogaeus for enzymes for which the parental allozymes are distinctive. we performed densitometry on phosphoglucomutase (pgm) and one glucose-6-phosphate isomerase locus (gpi-a) separated by cellulose acetate electrophoresis to determine if the parental species' allozymes are expressed in proportio ... | 1999 | 10531553 |
| mitochondrial dna variation and population genetic structure of the northern redbelly dace (phoxinus eos). | two sections of the control region and the genes coding for nadh dehydrogenase subunits 5 and 6 (nd-5/6) of mitochondrial dna (mtdna) were amplified from phoxinus eos with the polymerase chain reaction. both sections of the control region were sequenced directly while the nd-5/6 fragment was sequenced in from each end only. additionally, the entire nd-5/6 fragment was examined for sequence variation using rflp analysis. no sequence variation was detected in the control region among 70 individual ... | 1995 | 8564012 |
| extreme clonal uniformity of phoxinus eos/neogaeus gynogens (pisces: cyprinidae) among variable habitats in northern minnesota beaver ponds. | genetic surveys of parthenogenetic vertebrate populations have demonstrated a common pattern of relatively high degrees of clonal variation and the coexistence of numerous clones. in striking contrast, the phoxinus eos/phoxinus neogaeus/hybrid gynogen complex of cyprinid fishes exhibits no clonal variation within a northern minnesota drainage characterized by successional beaver ponds. gynogens were sampled from three habitats in each of four different pond types in a single drainage in voyageur ... | 1995 | 7761438 |