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[
WormBook,
2006]
Oscheius tipulae is a common soil nematode of the same family as C. elegans (Rhabditidae), which presents the same hermaphroditic mode of reproduction and is easily cultured in the same conditions. Oscheius tipulae has been used as a developmental genetic model system to study vulva formation. Compared to C. elegans, it has a simpler vulval cell lineage, a reduced competence group and a different mechanism of vulval cell fate patterning. The spectrum of vulval phenotypes obtained in genetic screens differs from that found in C. elegans. Its easy isolation from soil and the availability of numerous wild isolates of O. tipulae from all over the world facilitate population genetic and microevolutionary studies, especially of the evolution of cell lineage. The Oscheius genus also presents many species with interesting evolutionary changes in mode of reproduction, gonad development, body size, etc.
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[
New York Times,
1997]
Early this month, nearly a thousand biologists met here to discuss the affairs of a speck of protoplasm with a grandiloquent name, a barely visible, almost transparent worm called Caenorhabditis elegans. The worm holds the same secrets of life as other animals, but may be the first to yield them, an event that would deeply influence biology and medicine....
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[
Trends Genet,
1993]
A cascade of three protein kinases has emerged as a conserved functional module in a wide variety of signal transduction pathways in diverse organisms. In addition to this evolutionary conservation, studies in yeast demonstrate that versions of this module are used in different signalling pathways. Thus, homologous kinase cascades function in response to different stimuli in the same cell.
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[
Curr Biol,
1999]
Wnt signalling controls many different cell fate choices in a wide variety of animal species. Recent studies have revealed that regulatory interactions at several steps in the pathway can modify its outcome, helping to explain how the same pathway can, in different contexts, have very different characteristics and consequences.
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[
Trends in Genetics,
2004]
The complex relationship between the genotype and the phenotype constrains and biases phenotypic evolution. Indeed, random mutation can have non-random (anisotropic) effects on the phenotype. In this review, we propose an operational definition of the'phenotypic neighborhood' of a given genotype, as obtained after induced mutagenesis or in mutation accumulation lines, with examples of anisotropic distributions of phenotypes reached when exploring the vicinity of a genotype. We also compare the phenotypic neighborhood for a given developmental process among species, focusing on nematode vulva development. Finally, we compare the phenotypic neighborhood assessed by mutagenesis with the phenotypic spectrum of wild isolates of the same species and make inferences about the action of selection and/or drift on the same developmental process in
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[
Trends Genet,
2000]
Although they encode the same amino acids, synonymous codons are not all used at the same frequency. Such codon usage biases occur in most species and could be the result of mutational biases, natural selection acting on silent changes in DNA, or both. Selection on synonymous codon positions is thought to lead to a co-adaptation of codon usage and tRNA content to optimize the efficiency of translation. Such a selective pressure to reduce the cost of translation is expected to be stronger for genes that are expressed at high levels. In agreement with that model, in some unicellular organisms such as Escherichia coli or Saccharomyces cerevisiae, codons that are used preferentially correspond to the most abundant tRNA species, and there is a positive correlation between codon usage bias and the level of gene expression.
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[
Science,
1994]
Worms, butterflies, and chimpanzees all have the same body axes-head and tail, front and back, and left and right sides. How are these axes established during development? Is there a single molecular map used by most metazoan embryos or have similar coordinates been achieved during evolution by diverse routes? A comparison of the mechanisms that establish body axes in distantly related organisms can begin to answer this fundamental question.
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[
Science,
1996]
Single -gene mutations that extend the life-span of the worm Caenorhabditis elegans dramatically demonstrate the genetic basis of aging and may eventually lead to the elucidation of aging mechanisms. At the same time, evolution theory provides a powerful insight into the genetic basis of aging, and recent experiments are allowing these ideas to be tested and refined.
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[
Curr Opin Neurobiol,
2009]
A family of small molecules called ascarosides act as pheromones to control multiple behaviors in the nematode Caenorhabditis elegans. At picomolar concentrations, a synergistic mixture of at least three ascarosides produced by hermaphrodites causes male-specific attraction. At higher concentrations, the same ascarosides, perhaps in a different mixture, induce the developmentally arrested stage known as dauer. The production of ascarosides is strongly dependent on environmental conditions, although relatively little is known about the major variables and mechanisms of their regulation. Thus, male mating and dauer formation are linked through a common set of small molecules whose expression is sensitive to a given microenvironment, suggesting a model by which ascarosides regulate the overall life cycle of C. elegans.
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[
Cell Mol Life Sci,
2010]
The Caenorhabditis elegans one-cell embryo is a powerful system in which to study microtubule organization because this large cell assembles both meiotic and mitotic spindles within the same cytoplasm over the course of 1 h in a stereotypical manner. The fertilized oocyte assembles two consecutive acentrosomal meiotic spindles that function to reduce the replicated maternal diploid set of chromosomes to a single-copy haploid set. The resulting maternal DNA then unites with the paternal DNA to form a zygotic diploid complement, around which a centrosome-based mitotic spindle forms. The early C. elegans embryo is amenable to live-cell imaging and electron tomography, permitting a detailed structural comparison of the meiotic and mitotic modes of spindle assembly.