Genetic Variation in the Enzyme Esterase, Bioaccumulation and Life History Traits in the Earthworm Lumbricus Rubellus from a Metal Contaminated Area, Avonmouth, England

Ecotoxicology ◽  
2004 ◽  
Vol 13 (8) ◽  
pp. 773-786 ◽  
Author(s):  
Vibeke Simonsen ◽  
Janeck J. Scott-Fordsmand
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 110 (4) ◽  
pp. 403-410 ◽  
Author(s):  
Ned A Dochtermann ◽  
Tori Schwab ◽  
Monica Anderson Berdal ◽  
Jeremy Dalos ◽  
Raphaël Royauté

AbstractThe contribution of genetic variation to phenotypes is a central factor in whether and how populations respond to selection. The most common approach to estimating these influences is via the calculation of heritabilities, which summarize the contribution of genetic variation to phenotypic variation. Heritabilities also indicate the relative effect of genetic variation on phenotypes versus that of environmental sources of variation. For labile traits like behavioral responses, life history traits, and physiological responses, estimation of heritabilities is important as these traits are strongly influenced by the environment. Thus, knowing whether or not genetic variation is present within populations is necessary to understand whether or not these populations can evolve in response to selection. Here we report the results of a meta-analysis summarizing what we currently know about the heritability of behavior. Using phylogenetically controlled methods we assessed the average heritability of behavior (0.235)—which is similar to that reported in previous analyses of physiological and life history traits—and examined differences among taxa, behavioral classifications, and other biologically relevant factors. We found that there was considerable variation among behaviors as to how heritable they were, with migratory behaviors being the most heritable. Interestingly, we found no effect of phylogeny on estimates of heritability. These results suggest, first, that behavior may not be particularly unique in the degree to which it is influenced by factors other than genetics and, second, that those factors influencing whether a behavioral trait will have low or high heritability require further consideration.


2015 ◽  
Vol 53 (4) ◽  
pp. 447-453 ◽  
Author(s):  
Steffen Heelemann ◽  
Veronika Bäuerlein ◽  
Cornelia B. Krug ◽  
Karen J. Esler ◽  
Peter Poschlod ◽  
...  

2019 ◽  
Author(s):  
WU Blanckenhorn ◽  
V Llaurens ◽  
C Reim ◽  
Y Teuschl ◽  
E Postma

SUMMARYThe evolutionary potential of organisms depends on the presence of sufficient genetic variation for traits subject to selection, as well as on the genetic covariances among them. While genetic variation ultimately derives from mutation, theory predicts the depletion of genetic (co)variation under consistent directional or stabilizing selection in natural populations. We estimated and compared additive genetic (co)variances for several standard life history traits, including some for which this has never been assessed, before and after 24 generations of artificial selection on male size in the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) using a series of standard half-sib breeding experiments. As predicted, genetic variances (VA), heritabilities (h2) and evolvabilities (IA) of body size, development time, first clutch size, and female age at first clutch were lower after selection. As independent selection lines were crossed prior to testing, we can rule out that this reduction is due to genetic drift. In contrast to the variances, and against expectation, the additive genetic correlations between the sexes for development time and body size remained strong and positive (rA = 0.8–0.9), while the genetic correlation between these traits within the sexes tended to strengthen (but not significantly so). Our study documents that the effect of selection on genetic variance is predictable, whereas that on genetic correlations is not.


2014 ◽  
Vol 281 (1796) ◽  
pp. 20141039 ◽  
Author(s):  
Hanne Løvlie ◽  
Elina Immonen ◽  
Emil Gustavsson ◽  
Erem Kazancioğlu ◽  
Göran Arnqvist

There is a growing awareness of the influence of mitochondrial genetic variation on life-history phenotypes, particularly via epistatic interactions with nuclear genes. Owing to their direct effect on traits such as metabolic and growth rates, mitonuclear interactions may also affect variation in behavioural types or personalities (i.e. behavioural variation that is consistent within individuals, but differs among individuals). However, this possibility is largely unexplored. We used mitonuclear introgression lines, where three mitochondrial genomes were introgressed into three nuclear genetic backgrounds, to disentangle genetic effects on behavioural variation in a seed beetle. We found within-individual consistency in a suite of activity-related behaviours, providing evidence for variation in personality. Composite measures of overall activity of individuals in behavioural assays were influenced by both nuclear genetic variation and by the interaction between nuclear and mitochondrial genomes. More importantly, the degree of expression of behavioural and life-history phenotypes was correlated and mitonuclear genetic variation affected expression of these concerted phenotypes. These results show that mitonuclear genetic variation affects both behavioural and life-history traits, and they provide novel insights into the maintenance of genetic variation in behaviour and personality.


2018 ◽  
Author(s):  
Basten L. Snoek ◽  
Rita J.M. Volkers ◽  
Harm Nijveen ◽  
Carola Petersen ◽  
Philipp Dirksen ◽  
...  

AbstractLocal populations of the bacterivorous nematode Caenorhabditis elegans can be genetically almost as diverse as global populations. To investigate the effect of local genetic variation on heritable traits, we developed a new recombinant inbred line (RIL) population derived from four wild isolates. The wild isolates were collected from two closely located sites in France: Orsay and Santeuil. By crossing these four genetically diverse parental isolates a population of 200 RILs was constructed. RNA-seq was used to obtain sequence polymorphisms identifying almost 9000 SNPs variable between the four genotypes with an average spacing of 11 kb, possibly doubling the mapping resolution relative to currently available RIL panels. The SNPs were used to construct a genetic map to facilitate QTL analysis. Life history traits, such as lifespan, stress resistance, developmental speed and population growth were measured in different environments. For most traits substantial variation was found, and multiple QTLs could be detected, including novel QTLs not found in previous QTL analysis, for example for lifespan or pathogen responses. This shows that recombining genetic variation across C. elegans populations that are in geographical close proximity provides ample variation for QTL mapping. Taken together, we show that RNA-seq can be used for genotyping, that using more parents than the classical two parental genotypes to construct a RIL population facilitates the detection of QTLs and that the use of wild isolates permits analysis of local adaptation and life history trade-offs.


Sign in / Sign up

Export Citation Format

Share Document