Hakuna Nematoda: genetic and phenotypic diversity in African isolates of Caenorhabditis elegans and C. briggsae

Es, Dolgin; Ma, Félix; Cutter, Asher D.

doi:10.1038/sj.hdy.6801079

Cited by 77 publications

(110 citation statements)

References 47 publications

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“…Natural phenotypic variation has been explored in C. briggsae for several traits, including male tail morphology (Baird, 2001;Baird et al, 2005), vulval cell fate (Delattre and Félix, 2001;Dolgin et al, 2008) and fecundity (Fodor et al, 1983;Prasad et al, 2011). Our findings of heritable behaviour differences among wild genetic backgrounds that can exceed interspecific differences underscores the importance of quantifying intraspecific variability as a reference for contrasts between species.…”

Section: Variation Within C Elegans For Temperature-dependent Behaviourmentioning

confidence: 73%

“…When assayed for classic temperature-dependent behaviours on linear thermal gradients, we found that C. briggsae performs (Dolgin et al, 2008) and Cutter et al .…”

Section: Thermotaxis and Isothermal Tracking In C Briggsaementioning

confidence: 84%

“…Caenorhabditis elegans strains N2 and CB4856 and C. briggsae strains are all available from the Caenorhabditis Genetics Center (University of Minnesota, Minneapolis, MN, USA). These C. briggsae strains are wild isolates from distinct isogenic backgrounds (propagated from single selffertilizing worms) (see Table1) (Dolgin et al, 2008;. cholesterol in ethanol), were used as assay plates.…”

Section: Materials and Methods Strainsmentioning

confidence: 99%

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Temperature-dependent behaviours are genetically variable in the nematode Caenorhabditis briggsae

Stegeman

Mesquita

Ryu

et al. 2012

Journal of Experimental Biology

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SUMMARY Temperature-dependent behaviours inCaenorhabditis elegans, such as thermotaxis and isothermal tracking, are complex behavioural responses that integrate sensation, foraging and learning, and have driven investigations to discover many essential genetic and neural pathways. The ease of manipulation of the Caenorhabditis model system also has encouraged its application to comparative analyses of phenotypic evolution, particularly contrasts of the classic model C. elegans with C. briggsae. And yet few studies have investigated natural genetic variation in behaviour in any nematode. Here we measure thermotaxis and isothermal tracking behaviour in genetically distinct strains of C. briggsae, further motivated by the latitudinal differentiation in C. briggsae that is associated with temperature-dependent fitness differences in this species. We demonstrate that C. briggsae performs thermotaxis and isothermal tracking largely similar to that of C. elegans, with a tendency to prefer its rearing temperature. Comparisons of these behaviours among strains reveal substantial heritable natural variation within each species that corresponds to three general patterns of behavioural response. However, intraspecific genetic differences in thermal behaviour often exceed interspecific differences. These patterns of temperature-dependent behaviour motivate further development of C. briggsae as a model system for dissecting the genetic underpinnings of complex behavioural traits. Supplementary material available online at

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Section: Variation Within C Elegans For Temperature-dependent Behaviourmentioning

confidence: 73%

“…When assayed for classic temperature-dependent behaviours on linear thermal gradients, we found that C. briggsae performs (Dolgin et al, 2008) and Cutter et al .…”

Section: Thermotaxis and Isothermal Tracking In C Briggsaementioning

confidence: 84%

Section: Materials and Methods Strainsmentioning

confidence: 99%

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Temperature-dependent behaviours are genetically variable in the nematode Caenorhabditis briggsae

Stegeman

Mesquita

Ryu

et al. 2012

Journal of Experimental Biology

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“…However, the model tacitly assumes that deleterious mutations never reach appreciable frequency in the population, so it is reasonable to assume that subpopulations do not diverge substantially due to genetic drift, and positive selection is ignored in any case. Both C. elegans and C. briggsae show a specieswide clade structure, with two deep clades in C. elegans (Denver et al 2003) and three in C. briggsae (Dolgin et al 2008). The clades in C. briggsae largely reflect geography, with the three lineages representing temperate, tropical, and equatorial clades (Dolgin et al 2008), whereas the deep clades in C. elegans are apparently not geographically structured (but see Rockman and Kruglyak 2009).…”

Section: Wild Isolatesmentioning

confidence: 99%

“…Both C. elegans and C. briggsae show a specieswide clade structure, with two deep clades in C. elegans (Denver et al 2003) and three in C. briggsae (Dolgin et al 2008). The clades in C. briggsae largely reflect geography, with the three lineages representing temperate, tropical, and equatorial clades (Dolgin et al 2008), whereas the deep clades in C. elegans are apparently not geographically structured (but see Rockman and Kruglyak 2009). In addition, some collections contain several individuals from the same collecting location, but many locations include only a single individual.…”

Section: Wild Isolatesmentioning

confidence: 99%

Comparing Mutational and Standing Genetic Variability for Fitness and Size inCaenorhabditis briggsaeandC. elegans

Salomon

Ostrow

Phillips³

et al. 2009

Genetics

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The genetic variation present in a species depends on the interplay between mutation, population size, and natural selection. At mutation-(purifying) selection balance (MSB) in a large population, the standing genetic variance for a trait (V G ) is predicted to be proportional to the mutational variance for the trait (V M ); V M is proportional to the mutation rate for the trait. The ratio V M /V G predicts the average strength of selection (S ) against a new mutation. Here we compare V M and V G for lifetime reproductive success (% fitness) and body volume in two species of self-fertilizing rhabditid nematodes, Caenorhabditis briggsae and C. elegans, which the evidence suggests have different mutation rates. Averaged over traits, species, and populations within species, the relationship between V G and V M is quite stable, consistent with the hypothesis that differences among groups in standing variance can be explained by differences in mutational input. The average (homozygous) selection coefficient inferred from V M /V G is a few percent, smaller than typical direct estimates from mutation accumulation (MA) experiments. With one exception, the variance present in a worldwide sample of these species is similar to the variance present within a sample from a single locale. These results are consistent with specieswide MSB and uniform purifying selection, but genetic draft (hitchhiking) is a plausible alternative possibility.T HE genetic variation present in a species is a composite function of mutation, population size, and natural selection. The relationship between the standing genetic variance (V G ) and the per-generation input of genetic variance by mutation (the mutational variance, V M ) has a straightforward interpretation under two evolutionary scenarios. Under a deterministic mutation-(purifying) selection balance (MSB) model,where S is the average selection coefficient against a new mutation (Barton 1990;Crow 1993;Houle et al. 1996). The ratioS ) can be interpreted as the ''persistence time'' (t P ) of a new mutation, i.e., the expected number of generations a mutant allele remains in the (infinite) population before it is eliminated by selection (Crow 1993;Houle et al. 1996). The more deleterious the allele, the faster it is removed from the population. At the opposite extreme, under a strict neutral model of mutation-drift equilibrium (MDE), for self-fertilizing taxa, V G % 4N e V M , where N e is the effective population size (Lynch and Hill 1986). For a quantitative trait, V M ¼ UE(a 2 ), where U is the genomic mutation rate and a is the additive phenotypic effect of a new mutation (Lynch and Walsh 1998, p. 329).The unifying factor in these different scenarios is V M . Under both the MSB and MDE scenarios, we expect V G to be proportional to V M and thus the persistence timeto be constant if selection is uniform. Changes in the relationship between V G and V M among groups must be due to differences in natural selection. Thus, if t P differs between groups, the difference must be due to h...

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Natural reversal of left‐right gut/gonad asymmetry in C. elegans males is independent of embryonic chirality

Callander

Alcorn

Birsoy

et al. 2014

Genesis

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Anatomical left-right (L/R) handedness asymmetry in C. elegans is established in the four-cell embryo as a result of anteroposterior skewing of transverse mitotic spindles with a defined handedness. This event creates a chiral embryo and ultimately an adult body plan with fixed L/R positioning of internal organs and components of the nervous system. While this “dextral” configuration is invariant in hermaphrodites, it can be reversed by physical manipulation of the early embryo or by mutations that interfere with mitotic spindle orientation, which leads to viable, mirror-reversed (sinistral) animals. During normal development of the C. elegans male, the gonad develops on the right of the midline, with the gut bilaterally apposed on the left. However, we found that in males of the laboratory N2 strain and Hawaiian (“Hw”) wild isolate, the gut/gonad asymmetry is frequently reversed in a temperature-dependent manner, independent of normal embryonic chirality. We also observed sporadic errors in gonad migration occurring naturally during early larval stages of these and other wild strains; however, the incidence of such errors does not correlate with the frequency of L/R gut/gonad reversals in these strains. Analysis of N2/Hw hybrids and recombinant inbred advanced intercross lines (RIAILs) indicate that the L/R organ reversals are likely to result from recessively acting variations in multiple genes. Thus, unlike the highly reproducible L/R asymmetries of most structures in hermaphrodites, the L/R asymmetry of the male C. elegans body plan is less rigidly determined and subject to natural variation that is influenced by a multiplicity of genes.

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Hakuna Nematoda: genetic and phenotypic diversity in African isolates of Caenorhabditis elegans and C. briggsae

Cited by 77 publications

References 47 publications

Temperature-dependent behaviours are genetically variable in the nematode Caenorhabditis briggsae

Temperature-dependent behaviours are genetically variable in the nematode Caenorhabditis briggsae

Comparing Mutational and Standing Genetic Variability for Fitness and Size inCaenorhabditis briggsaeandC. elegans

Natural reversal of left‐right gut/gonad asymmetry in C. elegans males is independent of embryonic chirality

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