scholarly journals Ancestral population reconstitution from isofemale lines as a tool for experimental evolution

2016 ◽  
Vol 6 (20) ◽  
pp. 7169-7175 ◽  
Author(s):  
Pierre Nouhaud ◽  
Ray Tobler ◽  
Viola Nolte ◽  
Christian Schlötterer
Keyword(s):  
Experimental Evolution ◽  
Ancestral Population ◽  
Isofemale Lines

scholarly journals Gene-level quantitative trait mapping in an expandedC. elegansmultiparent experimental evolution panel

2019 ◽  
Author(s):  
Luke M. Noble ◽  
Matthew V. Rockman ◽  
Henrique Teotónio
Keyword(s):  
Experimental Evolution ◽  
Recombinant Inbred Lines ◽  
Single Gene ◽  
Ancestral Population ◽  
C Elegans ◽  
Quantitative Trait Mapping ◽  
Trait Variance ◽  
Gene Level ◽  
Evolution Experiment

ABSTRACTTheCaenorhabditis elegansmultiparental experimental evolution (CeMEE) panel is a collection of genome-sequenced, cryopreserved recombinant inbred lines useful for mapping the genetic basis and evolution of quantitative traits. We have expanded the resource with new lines and new populations, and here report updated additive and epistatic mapping simulations and the genetic and haplotypic composition of CeMEE version 2. Additive QTL explaining 3% of trait variance are detected with >80% power, and the median detection interval is around the length of a single gene on the highly recombinant chromosome arms. Although CeMEE populations are derived from a long-term evolution experiment, genetic structure is dominated by variation present in the ancestral population and is not obviously associated with phenotypic differentiation.C. elegansprovides exceptional experimental advantages for the study of phenotypic evolution.

scholarly journals Adaptation to a novel predator inDrosophila melanogaster: How well are we able to predict evolutionary responses?

2014 ◽  
Author(s):  
Michael DeNieu ◽  
William Pitchers ◽  
Ian Dworkin
Keyword(s):  
Natural Selection ◽  
Experimental Evolution ◽  
Phenotypic Selection ◽  
Ancestral Population ◽  
Wing Size ◽  
Short Term ◽  
Heritable Variation ◽  
Size And Shape ◽  
Evolutionary Trajectories ◽  
Short Term Prediction

Evolutionary theory is sufficiently well developed to allow for short-term prediction of evolutionary trajectories. In addition to the presence of heritable variation, prediction requires knowledge of the form of natural selection on relevant traits. While many studies estimate the form of natural selection, few examine the degree to which traits evolve in the predicted direction. In this study we examine the form of natural selection imposed by mantid predation on wing size and shape in the fruitfly,Drosophila melanogaster. We then evolve populations ofD. melanogasterunder predation pressure, and examine the extent to which wing size and shape have responded in the predicted direction. We demonstrate that wing form partially evolves along the predicted vector from selection, more so than for control lineages. Furthermore, we re-examined phenotypic selection after ~30 generations of experimental evolution. We observed that the magnitude of selection on wing size and shape was diminished in populations evolving with mantid predators, while the direction of the selection vector differed from that of the ancestral population for shape. We discuss these findings in the context of the predictability of evolutionary responses, and the need for fully multivariate approaches.

scholarly journals Partial selfing eliminates inbreeding depression while maintaining genetic diversity

2017 ◽  
Author(s):  
Ivo M. Chelo ◽  
Bruno Afonso ◽  
Sara Carvalho ◽  
Ioannis Theologidis ◽  
Christine Goy ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Inbreeding Depression ◽  
Experimental Evolution ◽  
Natural Populations ◽  
Ancestral Population ◽  
Origin And Evolution ◽  
C Elegans ◽  
Genome Wide ◽  
Adaptive Genetic Diversity

AbstractClassical theory on the origin and evolution of selfing and outcrossing relies on the role of inbreeding depression created by unlinked partially-deleterious recessive alleles to predict that individuals from natural populations predominantly self or outcross. Comparative data indicates, however, that maintenance of partial selfing and outcrossing at intermediate frequencies is common in nature. In part to explain the presence of mixed reproductive modes within populations, several hypotheses regarding the evolution of inbreeding depression have been put forward based on the complex interaction of linkage and identity disequilibrium among fitness loci, together with Hill-Robertson effects. We here ask what is the genetic basis of inbreeding depression so that populations with intermediate selfing rates can eliminate it while maintain potentially adaptive genetic diversity. For this, we use experimental evolution in the nematode C. elegans under partial selfing and compare it to the experimental evolution of populations evolved under exclusive selfing and predominant outcrossing. We find that the ancestral risk of extinction upon enforced inbreeding by selfing is maintained when populations evolve under predominant outcrossing, but reduced when populations evolve under partial or exclusive selfing. Analysis of genome-wide single-nucleotide polymorphism (SNP) during experimental evolution and after enforced inbreeding suggests that, under partial selfing, populations were purged of unlinked deleterious recessive alleles that segregate in the ancestral population, which in turn allowed the expression of unlinked overdominant fitness loci. Taken together, these observations indicate that populations evolving under partial selfing gain the short-term benefits of selfing, in purging deleterious recessive alleles, but also the long-term benefits of outcrossing, in maintaining genetic diversity that may important for future adaptation.

scholarly journals Experimental evolution of UV resistance in a phage

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5190 ◽  
Author(s):  
Eric F. Tom ◽  
Ian J. Molineux ◽  
Matthew L. Paff ◽  
James J. Bull
Keyword(s):  
Experimental Evolution ◽  
High Frequency ◽  
Phage Therapy ◽  
Selection Process ◽  
Gene Mutations ◽  
Ancestral Population ◽  
Uv Resistance ◽  
Structural Genes ◽  
Error Catastrophe ◽  
Improvement In Survival

The dsDNA bacteriophage T7 was subjected to 30 cycles of lethal ultraviolet light (UV) exposure to select increased resistance to UV. The exposure effected a 0.9999 kill of the ancestral population, and survival of the ending population was nearly 50-fold improved. At the end point, a 2.1 kb deletion of early genes and three substitutions in structural-genes were the only changes observed at high frequency throughout the 40 kb genome; no changes were observed in genes affecting DNA metabolism. The deletion accounted for only a two-fold improvement in survival. One possible explanation of its benefit is that it represents an error catastrophe, whereby the genome experiences a reduced mutation rate. The mechanism of benefit provided by the three structural-gene mutations remains unknown. The results offer some hope of artificially evolving greater protection against sunlight damage in applications of phage therapy to plants, but the response of T7 is weak compared to that observed in bacteria selected to resist ionizing radiation. Because of the weak response, mathematical analysis of the selection process was performed to determine how the protocol might have been modified to achieve a greater response, but the greatest protection may well come from evolving phages to bind materials that block the UV.

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