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

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.

2021 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E. Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll

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.


Author(s):  
Gaotian Zhang ◽  
Jake D Mostad ◽  
Erik C Andersen

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.


2018 ◽  
Author(s):  
Jacob W. Malcom ◽  
Thomas E. Juenger ◽  
Mathew A. Leibold

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.


2019 ◽  
Vol 224 (4) ◽  
pp. 1642-1656 ◽  
Author(s):  
Pavel Trávníček ◽  
Martin Čertner ◽  
Jan Ponert ◽  
Zuzana Chumová ◽  
Jana Jersáková ◽  
...  

2009 ◽  
Vol 60 (8) ◽  
pp. 861 ◽  
Author(s):  
D. J. Colgan ◽  
P. da Costa

Investigations of estuarine taxa can provide a perspective on phylogeography that complements studies of marine littoral organisms. For example, reductions in gene flow between populations and increased genetic structuring would be expected in estuarine species. The substantial amount of information about marine species and the habitat diversity along long latitudinal spans makes south-eastern Australia an excellent potential location for comparing marine and estuarine taxa. To investigate this potential, we studied the phylogeography of the two species in the estuarine gastropod genus Tatea. These have extensive and broadly overlapping distributions that encompass known marine phylogeographic boundaries. Against expectation, both Tatea species showed a remarkable lack of geographic and inter-specific variability in mitochondrial 12S rRNA (107 specimens) and cytochrome c oxidase subunit I (39) DNA sequences. No major phylogeographic discontinuities were revealed in either species and there was minimal haplotype divergence between them for either 12S rRNA or COI. The patterns of mitochondrial DNA variation discovered in Tatea may be due to a recent selective sweep or range expansion from a population in which there was little variability. Both possibilities are complicated by having to explain the similarity of the patterns in the two species.


Heredity ◽  
2004 ◽  
Vol 93 (4) ◽  
pp. 371-378 ◽  
Author(s):  
J S Christie ◽  
J A Castro ◽  
P Oliver ◽  
A Picornell ◽  
M M Ramon ◽  
...  

Genome ◽  
1994 ◽  
Vol 37 (1) ◽  
pp. 33-35 ◽  
Author(s):  
C. Anna Toline ◽  
Michael Lynch

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.


1990 ◽  
Vol 47 (3) ◽  
pp. 533-543 ◽  
Author(s):  
Louis Bernatchez ◽  
Julian J. Dodson

Mitochondrial DNA (mtDNA) restriction analyses were done to test the hypothesis that river populations of anadromous cisco from James-Hudson Bays that exhibit life-history variations are reproductively isolated. MtDNA variation among 141 cisco (Coregonus artedii) from eight rivers was studied with eight hexameric, four multihexameric and one multipentameric restriction enzymes which generated a mean of 78 fragments per fish. Pair-wise sequence divergence estimates among the 19 mtDNA clones resolved were generally low but highly variable (mean: 0.52%, range: 0.08 to 1.03%). UPGMA and Wagner parsimony analysis revealed two major clonal groups which differed in diversity and geographic distribution; the more diversified (nucleon diversity index; 0.70) and less diversified (0.31) groups were twice as abundant in James and Hudson Bays, respectively. This suggests that cisco of James-Hudson Bays are derived from two glacial refugia and that they recolonized the area by two major postglacial routes. The frequency distribution analysis of all defined clones revealed significant stock discreteness among Hudson Bay populations and a lack of population subdivision in James Bay. The genetic structuring and diversity of anadromous cisco in James-Hudson Bay is discussed in relation to historical biogeographical events and to interactions of various life-history stages with the physical oceanographic environment.


2009 ◽  
Vol 100 (1) ◽  
pp. 9-17 ◽  
Author(s):  
M.-P. Chapuis ◽  
L. Crespin ◽  
A. Estoup ◽  
A. Augé-Sabatier ◽  
A. Foucart ◽  
...  

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.


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