Allen orr and the genetics of adaptation

Evolution ◽  
2021 ◽  
Author(s):  
Tim Connallon ◽  
Kathryn A. Hodgins
Keyword(s):  
Genetics Of Adaptation

Rapid Evolutionary Responses in Cichlids: Genetics of Adaptation, Morphology and Taxonomic Implications

2021 ◽  
pp. 247-283 ◽  
Author(s):  
Jacco C. van Rijssel ◽  
Rob C. M. de Jong ◽  
Mary A. Kishe ◽  
Frans Witte
Keyword(s):  
Taxonomic Implications ◽  
Genetics Of Adaptation

scholarly journals Genomics of adaptation and speciation in cichlid fishes: recent advances and analyses in African and Neotropical lineages

2012 ◽  
Vol 367 (1587) ◽  
pp. 385-394 ◽  
Author(s):  
Shaohua Fan ◽  
Kathryn R. Elmer ◽  
Axel Meyer
Keyword(s):  
Expressed Sequence Tag ◽  
Population Level ◽  
Genomic Diversity ◽  
Cichlid Fishes ◽  
Exciting Opportunity ◽  
Phenotypic Diversification ◽  
Genetics Of Adaptation ◽  
Available Information ◽  
African Cichlids ◽  
Expressed Sequence

Cichlid fishes are remarkably phenotypically diverse and species-rich. Therefore, they provide an exciting opportunity for the study of the genetics of adaptation and speciation by natural and sexual selection. Here, we review advances in the genomics and transcriptomics of cichlids, particularly regarding ecologically relevant differences in body shape, trophic apparatus, coloration and patterning, and sex determination. Research conducted so far has focused almost exclusively on African cichlids. To analyse genomic diversity and selection in a Neotropical radiation, we conducted a comparative transcriptomic analysis between sympatric, ecologically divergent crater-lake Midas cichlids (Lake Xiloá Amphilophus amarillo and Amphilophus sagittae ). We pyrosequenced (Roche 454) expressed sequence tag (EST) libraries and generated more than 178 000 000 ESTs and identified nine ESTs under positive selection between these sister species ( K a/ K s > 1). None of these ESTs were found to be under selection in African cichlids. Of 11 candidate genes for ecomorphological differentiation in African cichlids, none showed signs of selection between A. amarillo and A. sagittae . Although more population-level studies are now needed to thoroughly document patterns of divergence during speciation of cichlids, available information so far suggests that adaptive phenotypic diversification in Neotropical and African cichlids may be evolving through non-parallel genetic bases.

scholarly journals Genetics of adaptation: Experimental test of a biotic mechanism driving divergence in traits and genes

2019 ◽  
Vol 3 (5) ◽  
pp. 513-520 ◽  
Author(s):  
Diana J. Rennison ◽  
Seth M. Rudman ◽  
Dolph Schluter
Keyword(s):  
Experimental Test ◽  
Genetics Of Adaptation

scholarly journals The evolutionary genetics of adaptation: a simulation study

1999 ◽  
Vol 74 (3) ◽  
pp. 207-214 ◽  
Author(s):  
H. ALLEN ORR
Keyword(s):  
Geometric Model ◽  
Experimental Studies ◽  
Evolutionary Genetics ◽  
Exponential Distributions ◽  
Phenotypic Effect ◽  
Gene Effects ◽  
Number Of Factors ◽  
Number Of Genes ◽  
History Of ◽  
Genetics Of Adaptation

It is now clear that the genetic basis of adaptation does not resemble that assumed by the infinitesimal model. Instead, adaptation often involves a modest number of factors of large effect and a greater number of factors of smaller effect. After reviewing relevant experimental studies, I consider recent theoretical attempts to predict the genetic architecture of adaptation from first principles. In particular, I review the history of work on Fisher's geometric model of adaptation, including recent studies which suggest that adaptation should be characterized by exponential distributions of gene effects. I also present the results of new simulation studies that test the robustness of this finding. I explore the effects of changes in the distribution of mutational effects (absolute versus relative) as well as in the nature of the character studied (total phenotypic effect versus single characters). The results show that adaptation towards a fixed optimum is generally characterized by an exponential effects trend.The situation to which these studies point is not one of a large number of genes all with more or less equal effect. It seems, rather, that a small number of genes with large effects are responsible for most of the response, the remainder of the response being due to a larger number of loci with small effects.D. S. Falconer (1981)

Testing hypotheses regarding the genetics of adaptation

Genetica ◽  
2005 ◽  
Vol 123 (1-2) ◽  
pp. 15-24 ◽  
Author(s):  
Patrick C. Phillips
Keyword(s):  
Testing Hypotheses ◽  
Genetics Of Adaptation

scholarly journals Coloration and the Genetics of Adaptation

PLoS Biology ◽  
2007 ◽  
Vol 5 (9) ◽  
pp. e250 ◽  
Author(s):  
Nicholas I Mundy
Keyword(s):  
Genetics Of Adaptation

scholarly journals Dominance shifts increase the likelihood of soft selective sweeps

2021 ◽  
Author(s):  
Pavitra Muralidhar ◽  
Carl Veller
Keyword(s):  
Selective Sweep ◽  
Primary Source ◽  
Pesticide Use ◽  
Selective Sweeps ◽  
Multiple Alleles ◽  
Standing Variation ◽  
Haplotypic Diversity ◽  
Evolutionary Rescue ◽  
Genetics Of Adaptation ◽  
Soft Selective Sweeps

AbstractGenetic models of adaptation to a new environment have typically assumed that the alleles involved maintain a constant fitness dominance across the old and new environments. However, theories of dominance suggest that this should often not be the case. Instead, the alleles involved should frequently shift from recessive deleterious in the old environment to dominant beneficial in the new environment. Here, we study the consequences of these expected dominance shifts for the genetics of adaptation to a new environment. We find that dominance shifts increase the likelihood that adaptation occurs from the standing variation, and that multiple alleles from the standing variation are involved (a soft selective sweep). Furthermore, we find that expected dominance shifts increase the haplotypic diversity of selective sweeps, rendering soft sweeps more detectable in small genomic samples. In cases where an environmental change threatens the viability of the population, we show that expected dominance shifts of newly beneficial alleles increase the likelihood of evolutionary rescue and the number of alleles involved. Finally, we apply our results to a well-studied case of adaptation to a new environment: the evolution of pesticide resistance at the Ace locus in Drosophila melanogaster. We show that, under reasonable demographic assumptions, the expected dominance shift of resistant alleles causes soft sweeps to be the most frequent outcome in this case, with the primary source of these soft sweeps being the standing variation at the onset of pesticide use, rather than recurrent mutation thereafter.

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