Mutational divergence of life-history traits in an obligate parthenogen

Genome ◽  
1994 ◽  
Vol 37 (1) ◽  
pp. 33-35 ◽  
Author(s):  
C. Anna Toline ◽  
Michael Lynch
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Sole Source ◽  
Morphological Characters ◽  
The Other ◽  
Life History Trait ◽  
Adaptive Changes ◽  
Significant Divergence ◽  
Polygenic Variation

Three lines of obligately parthenogenetic Daphnia were allowed to diverge for a 4-year period (approximately 150 generations) with mutation as the sole source of variability. Life-history traits and morphological characters were then surveyed for between-line differences. Significant divergence was found with respect to both number and size of offspring, with no difference in total offspring biomass. No significant differences were found in any of the other characters. These results confirm the hypothesis that purely asexual lines can accumulate enough polygenic variation via mutation to support potentially adaptive changes on a microevolutionary time scale.Key words: Daphnia, life-history trait, mutational divergence, microevolution.

scholarly journals Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments

2021 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E. Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll
Keyword(s):  
Life History ◽  
Large Scale ◽  
Life History Traits ◽  
Genetic Correlations ◽  
Stress Factors ◽  
Life History Trait ◽  
Adaptive Landscape ◽  
Heterogeneous Environments ◽  
Growth Responses ◽  
Trade Offs

AbstractThe adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen’s ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.

scholarly journals Natural variation in fecundity is correlated with species-wide levels of divergence in Caenorhabditis elegans

2021 ◽  
Author(s):  
Gaotian Zhang ◽  
Jake D Mostad ◽  
Erik C Andersen
Keyword(s):  
Life History ◽  
Caenorhabditis Elegans ◽  
Life History Traits ◽  
Life History Trait ◽  
Selective Sweeps ◽  
C Elegans ◽  
Genome Wide ◽  
Genetic Complexity ◽  
Genomic Regions ◽  
Global Population

Abstract Life history traits underlie the fitness of organisms and are under strong natural selection. A new mutation that positively impacts a life history trait will likely increase in frequency and become fixed in a population (e.g. a selective sweep). The identification of the beneficial alleles that underlie selective sweeps provides insights into the mechanisms that occurred during the evolution of a species. In the global population of Caenorhabditis elegans, we previously identified selective sweeps that have drastically reduced chromosomal-scale genetic diversity in the species. Here, we measured the fecundity of 121 wild C. elegans strains, including many recently isolated divergent strains from the Hawaiian islands and found that strains with larger swept genomic regions have significantly higher fecundity than strains without evidence of the recent selective sweeps. We used genome-wide association (GWA) mapping to identify three quantitative trait loci (QTL) underlying the fecundity variation. Additionally, we mapped previous fecundity data from wild C. elegans strains and C. elegans recombinant inbred advanced intercross lines that were grown in various conditions and detected eight QTL using GWA and linkage mappings. These QTL show the genetic complexity of fecundity across this species. Moreover, the haplotype structure in each GWA QTL region revealed correlations with recent selective sweeps in the C. elegans population. North American and European strains had significantly higher fecundity than most strains from Hawaii, a hypothesized origin of the C. elegans species, suggesting that beneficial alleles that caused increased fecundity could underlie the selective sweeps during the worldwide expansion of C. elegans.

scholarly journals Loci, genes, and gene networks associated with life history variation in a model ecological organism,Daphnia pulex(complex)

2018 ◽  
Author(s):  
Jacob W. Malcom ◽  
Thomas E. Juenger ◽  
Mathew A. Leibold
Keyword(s):  
Gene Expression ◽  
Genetic Variation ◽  
Life History ◽  
Molecular Basis ◽  
Life History Traits ◽  
Evolutionary Dynamics ◽  
Daphnia Pulex ◽  
Life History Trait ◽  
Life History Variation ◽  
Trait Variation

ABSTRACTBackgroundIdentifying the molecular basis of heritable variation provides insight into the underlying mechanisms generating phenotypic variation and the evolutionary history of organismal traits. Life history trait variation is of central importance to ecological and evolutionary dynamics, and contemporary genomic tools permit studies of the basis of this variation in non-genetic model organisms. We used high density genotyping, RNA-Seq gene expression assays, and detailed phenotyping of fourteen ecologically important life history traits in a wild-caught panel of 32Daphnia pulexclones to explore the molecular basis of trait variation in a model ecological species.ResultsWe found extensive phenotypic and a range of heritable genetic variation (~0 < H2< 0.44) in the panel, and accordingly identify 75-261 genes—organized in 3-6 coexpression modules—associated with genetic variation in each trait. The trait-related coexpression modules possess well-supported promoter motifs, and in conjunction with marker variation at trans- loci, suggest a relatively small number of important expression regulators. We further identify a candidate genetic network with SNPs in eight known transcriptional regulators, and dozens of differentially expressed genes, associated with life history variation. The gene-trait associations include numerous un-annotated genes, but also support several a priori hypotheses, including an ecdysone-induced protein and several Gene Ontology pathways.ConclusionThe genetic and gene expression architecture ofDaphnialife history traits is complex, and our results provide numerous candidate loci, genes, and coexpression modules to be tested as the molecular mechanisms that underlieDaphniaeco-evolutionary dynamics.

scholarly journals Plasmodium infection decreases fecundity and increases survival of mosquitoes

2012 ◽  
Vol 279 (1744) ◽  
pp. 4033-4041 ◽  
Author(s):  
J. Vézilier ◽  
A. Nicot ◽  
S. Gandon ◽  
A. Rivero
Keyword(s):  
Life History ◽  
Insecticide Resistance ◽  
Life History Traits ◽  
Experimental System ◽  
Adaptive Strategy ◽  
Genetic Variations ◽  
The Other ◽  
Plasmodium Infection ◽  
Trade Off ◽  
The One

Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium- infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium- infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

Mitochondrial cytochrome oxidase I in tetranychid mites: a comparison between molecular phylogeny and changes of morphological and life history traits

1996 ◽  
Vol 86 (4) ◽  
pp. 407-417 ◽  
Author(s):  
Maria Navajas ◽  
Jean Gutierrez ◽  
Jacques Lagnel ◽  
Pierre Boursot
Keyword(s):  
Life History ◽  
Cytochrome Oxidase ◽  
Life History Traits ◽  
Codon Position ◽  
Morphological Characters ◽  
Mitochondrial Cytochrome ◽  
Mode Of Reproduction ◽  
The Third ◽  
Mode Of Life ◽  
Mitochondrial Cytochrome Oxidase

AbstractSpider mites, Tetranychidae, represent one of the most cosmopolitan and economically important groups of terrestrial arthropods; however, many aspects of their evolutionary relationships remain uncertain. We sequenced part of the mitochondrial cytochrome oxidase subunit I (COI) gene in 20 species of phytophagous mites belonging to nine genera and two families (Tetranychidae and Tenuipalpidae), including several agricultural pests. As eported in insects, the sequences were extremely rich in A + T (75% on average), especially in the third codon position (95%). However, one of the genera we studied had a significantly lower A + T content (69% on average, 78% in the third codon position), showing that base composition can change substantially over short periods of time. Most interspecific differences were transversions and their number increased steadily with the number of non-synonymous differences, while the number of transitions remained constant. The phylogeny based on COI sequences was inferred using the maximum likelihood method. The results are compatible as a whole with the traditional classification based on morphological characters, but call for some minor taxonomic revisions. Some morphological characters and life history traits (mode of reproduction, adaptation to the host plant) were also analysed within this phylogenetic framework. At the family level, one can see a trend towards thelytoky becoming rarer compared to the general mode of reproduction of the group, arrhenotoky. There is also an evolutionary tendency towards a more complex mode of life, with the production of silk webs and correlated changes of the locomotion apparatus. However, in the Tetranychidae there seems to have been convergent evolution of these morphological characters together with independent development of a common adaptation to this mode of life in different genera.

scholarly journals Life history traits of five ground beetle (Coleoptera: Carabidae) species common in Honshu Island, Japan

2020 ◽  
Vol 66 (Suppl.) ◽  
pp. 185-198
Author(s):  
Sonomi Shibuya ◽  
Keizi Kiritani ◽  
Kenji Fukuda
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Environmental Changes ◽  
Wing Length ◽  
Ground Beetle ◽  
The Other ◽  
Gut Contents ◽  
Generalist Predator ◽  
Flight Muscles ◽  
Honshu Island

Ground beetles have been used as bioindicators for monitoring environmental changes. However, to interpret monitoring results, we need further information on their life history traits. We selected Harpalus griseus, H. eous, H. tridens, Synuchus cycloderus and Carabus procerulus, species common in Honshu Island, Japan. We examined their hind wings, flight muscles, gut contents and ovarian eggs to understand their flight activity, feeding traits and reproductive strategies. The three Harpalus species showed wing length / body length ratios (W/B) of 0.88 - 0.99. In H. tridens, the proportion of individuals with flight muscles and caught in aerial traps was lower than in the other two. S. cycloderus was macropterous with a W/B ratio of 0.75, but no individuals were caught in aerial traps, and none possessed flight muscles. C. procerulus was brachypterous. The three Harpalus species fed mainly on seeds and partly on arthropods. S. cycloderus was a generalist predator. Gut contents of C. procerulus consisted of amorphous fluid, suggesting extra-oral digestion. Egg type was categorized by the number and size of ovarian eggs. S. cycloderus had many-small eggs, while the other four had few but large eggs.

Parental crowding influences life-history traits inLocusta migratoriafemales

2009 ◽  
Vol 100 (1) ◽  
pp. 9-17 ◽  
Author(s):  
M.-P. Chapuis ◽  
L. Crespin ◽  
A. Estoup ◽  
A. Augé-Sabatier ◽  
A. Foucart ◽  
...  
Keyword(s):  
Life History ◽  
Parental Influence ◽  
Life History Traits ◽  
Locusta Migratoria ◽  
Developmental Time ◽  
Life History Trait ◽  
Offspring Size ◽  
Potential Implication ◽  
Generational Effects ◽  
History Of

AbstractParental environments could play an important role in controlling insect outbreaks, provided they influence changes in physiological, developmental or behavioural life-history traits related to fluctuations in population density. However, the potential implication of parental influence in density-related changes in life-history traits remains unclear in many insects that exhibit fluctuating population dynamics, particularly locusts. In this study, we report a laboratory experiment, which enabled us to characterize the life-history trait modifications induced by parental crowding of female individuals from a frequently outbreaking population ofLocusta migratoria(Linnaeus) (Orthoptera: Acrididae). We found that a rearing history of crowding led to reduced female oviposition times and increased offspring size but did not affect the developmental time, survival, fecundity, and the sex-ratio and the number of offspring. Because all studied females were raised in a common environment (isolation conditions), these observed reproductive differences are due to trans-generational effects induced by density. We discuss the ecological and evolutionary implications of the observed density-dependent parental effects on the life-history ofL. migratoria.

scholarly journals Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments

2020 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll
Keyword(s):  
Life History ◽  
Large Scale ◽  
Life History Traits ◽  
Stress Factors ◽  
Life History Trait ◽  
Adaptive Landscape ◽  
Heterogeneous Environments ◽  
Growth Responses ◽  
Zymoseptoria Tritici ◽  
Trade Offs

The adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used multi-trait genome-wide association mapping. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified numerous pleiotropic SNPs with conflicting effects on host colonization and survival in stressful environments. Such genetic constraints are likely limiting the pathogen's ability to cause host damage and could be exploited for pathogen control. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.

scholarly journals Life history evolution and phenotypic plasticity in parasitic eyebrights (Euphrasia, Orobanchaceae)

2018 ◽  
Author(s):  
Alex D. Twyford ◽  
Natacha Frachon ◽  
Edgar L. Y. Wong ◽  
Chris Metherell ◽  
Max R. Brown
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Reproductive Success ◽  
Life History Traits ◽  
Common Garden ◽  
Parasitic Plant ◽  
Life History Strategies ◽  
Life History Trait ◽  
Lifetime Reproductive Success ◽  
Host Quality

ABSTRACTPremise of the studyParasite lifetime reproductive success is determined by both genetic variation and phenotypically plastic life history traits that respond to host quality and external environment. Here, we use the generalist parasitic plant genus Euphrasia to investigate life history trait variation, in particular whether there is a trade-off between growth and reproduction, and how life history traits are affected by host quality.MethodsWe perform a common garden experiment to evaluate life history trait differences between eleven Euphrasia taxa grown on a common host, document phenotypic plasticity when a single Euphrasia species is grown on eight different hosts, and relate our observations to trait differences recorded in the wild.Key resultsEuphrasia exhibit a range of life history strategies that differ between species that transition rapidly to flower at the expense of early season growth, and those that invest in vegetative growth and delay flowering. Many life history traits show extensive phenotypic plasticity in response to host quality and demonstrate the costs of attaching to a low-quality host.ConclusionsCommon garden experiments reveal trait differences between taxonomically complex Euphrasia species that are characterised by postglacial speciation and hybridisation. Our experiments suggest life history strategies in this generalist parasitic plant genus are the product of natural selection on traits related to growth and flowering. However, host quality may be a primary determinant of lifetime reproductive success.

Life history trait differences between a lake and a stream-dwelling population of the Pyrenean brook newt (Calotriton asper)

2014 ◽  
Vol 35 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Neus Oromi ◽  
Fèlix Amat ◽  
Delfi Sanuy ◽  
Salvador Carranza
Keyword(s):  
Mitochondrial Dna ◽  
Life History ◽  
Life History Traits ◽  
Climatic Conditions ◽  
Life History Trait ◽  
Genetic Structuring ◽  
Dna Variation ◽  
Juvenile Dispersal ◽  
Fast Running ◽  
High Altitude Lake

The Pyrenean brook newt (Calotriton asper) is a salamandrid that mostly lives in fast running and cold mountain-streams, although some populations are also found in lakes. In the present work, we report in detail on the occurrence of facultative paedomorphosis traits in a population from a Pyrenean high altitude lake. We compare its morphology, life history traits and mitochondrial DNA variation with a nearby lotic metamorphic population. Our results indicate that the lacustrine newts are smaller and present a less developed sexual dimorphism, smooth skin, and that 53% of the adults retain gills at different degrees of development, but not gill slits. Although both populations and sexes have the same age at sexual maturity (four years), the lacustrine population presents higher longevity (12 and 9 years for males and females, respectively) than the one living in the stream (8 and 9 years). The variation on the climatic conditions at altitudinal scale is probably the main cause of the differences in life history traits found between the two populations. The food availability, which could to be limiting in the lacustrine population, is another factor that can potentially affect body size. These results are congruent with the significant mitochondrial DNA genetic isolation between populations, probably a consequence of the lack of juvenile dispersal. We found low cytochrome b variability and significant genetic structuring in the lake population that is very remarkably considering the short distance to the nearby stream population and the whole species’ pattern. We suggest that a bottleneck effect and/or phenotypic plasticity may have resulted in the appearance of a paedomorphic morph in the lake.

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