scholarly journals THE INTERPLAY BETWEEN LOCAL ECOLOGY, DIVERGENT SELECTION, AND GENETIC DRIFT IN POPULATION DIVERGENCE OF A SEXUALLY ANTAGONISTIC FEMALE TRAIT

Evolution ◽  
2014 ◽  
Vol 68 (7) ◽  
pp. 1934-1946 ◽  
Author(s):  
Kristina Karlsson Green ◽  
Erik I. Svensson ◽  
Johannes Bergsten ◽  
Roger Härdling ◽  
Bengt Hansson
Keyword(s):  
Genetic Drift ◽  
Divergent Selection ◽  
Population Divergence ◽  
Local Ecology

scholarly journals Climate-driven divergent selection in a foundation tree species: QST-FST evidence from multiple common gardens

2021 ◽  
Author(s):  
Hillary Cooper ◽  
Gerard Allan ◽  
Lela Andrews ◽  
Rebecca Best ◽  
Kevin Grady ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Tree Species ◽  
Divergent Selection ◽  
Population Variation ◽  
Population Divergence ◽  
Phenotypic Traits ◽  
Local Conditions ◽  
Basal Diameter ◽  
Common Gardens ◽  
Fremont Cottonwood

Widespread tree species span large climatic gradients that often lead to high levels of local adaptation and phenotypic divergence across their range. To evaluate the relative roles of selection and drift in driving divergence in phenotypic traits, we compared molecular and quantitative genetic variation in Populus fremontii (Fremont cottonwood), using data from > 9000 SNPs and genotypes from 16 populations reciprocally planted in three common gardens that span the species’ climatic range. We present three major findings: 1) There is significant within- and among-population variation in functional traits expressed in each of the common gardens. 2) There is evidence from all three gardens that population divergence in leaf phenology and specific leaf area has been driven by divergent selection (QST > FST). In contrast, QST-FST comparisons for performance traits like height and basal diameter were highly dependent on growing environment, indicating divergent, stabilizing, or no selection across the three gardens. We show this is likely due to local adaptation of source populations to contrasting growing environments. 3) Climate is a primary selective force driving trait divergence, where the traits showing the strongest correlations with a genotype’s provenance climate also had the highest QST values. We conclude that climatic gradients have contributed to significant phenotypic differences and local adaptation in Fremont cottonwood. These results are important because as climate is changing much more rapidly, traits such as phenology that are finely tuned to local conditions may now be subject to intense selection or quickly become maladaptive.

scholarly journals Divergent selection and drift shape the genomes of two avian sister species spanning a saline-freshwater ecotone

2018 ◽  
Author(s):  
Jennifer Walsh ◽  
Gemma V. Clucas ◽  
Matthew D. MacManes ◽  
W. Kelley Thomas ◽  
Adrienne I. Kovach
Keyword(s):  
Genetic Drift ◽  
Tidal Marsh ◽  
Divergent Selection ◽  
Sister Species ◽  
Tidal Marshes ◽  
Valuable Insight ◽  
Terrestrial Vertebrates ◽  
Genome Wide ◽  
Habitat Gradient

AbstractThe role of species divergence due to ecologically-based divergent selection – or ecological speciation – in generating and maintaining biodiversity is a central question in evolutionary biology. Comparison of the genomes of phylogenetically related taxa spanning a selective habitat gradient enables discovery of divergent signatures of selection and thereby provides valuable insight into the role of divergent ecological selection in speciation. Tidal marsh ecosystems provide tractable opportunities for studying organisms’ adaptations to selective pressures that underlie ecological divergence. Sharp environmental gradients across the saline-freshwater ecotone within tidal marshes present extreme adaptive challenges to terrestrial vertebrates. Here we sequence 20 whole genomes of two avian sister species endemic to tidal marshes – the Saltmarsh Sparrow (Ammodramus caudacutus) and Nelson’s Sparrow (A. nelsoni) – to evaluate the influence of selective and demographic processes in shaping genome-wide patterns of divergence. Genome-wide divergence between these two recently diverged sister species was notably high (genome-wide FST = 0.32). Against a background of high genome-wide divergence, regions of elevated divergence were widespread throughout the genome, as opposed to focused within islands of differentiation. These patterns may be the result of genetic drift acting during past tidal march colonization events in addition to divergent selection to different environments. We identified several candidate genes that exhibited elevated divergence between Saltmarsh and Nelson’s sparrows, including genes linked to osmotic regulation, circadian rhythm, and plumage melanism – all putative candidates linked to adaptation to tidal marsh environments. These findings provide new insights into the roles of divergent selection and genetic drift in generating and maintaining biodiversity.

scholarly journals Genomic signatures of spatially divergent selection at clownfish range margins

2021 ◽  
Vol 288 (1952) ◽  
pp. 20210407
Author(s):  
René D. Clark ◽  
Matthew L. Aardema ◽  
Peter Andolfatto ◽  
Paul H. Barber ◽  
Akihisa Hattori ◽  
...  
Keyword(s):  
Gene Flow ◽  
Candidate Genes ◽  
Local Adaptation ◽  
Genetic Drift ◽  
Divergent Selection ◽  
Species Range ◽  
Evolutionary Forces ◽  
The Core ◽  
Range Edge ◽  
Genomic Signatures

Understanding how evolutionary forces interact to drive patterns of selection and distribute genetic variation across a species' range is of great interest in ecology and evolution, especially in an era of global change. While theory predicts how and when populations at range margins are likely to undergo local adaptation, empirical evidence testing these models remains sparse. Here, we address this knowledge gap by investigating the relationship between selection, gene flow and genetic drift in the yellowtail clownfish, Amphiprion clarkii, from the core to the northern periphery of the species range. Analyses reveal low genetic diversity at the range edge, gene flow from the core to the edge and genomic signatures of local adaptation at 56 single nucleotide polymorphisms in 25 candidate genes, most of which are significantly correlated with minimum annual sea surface temperature. Several of these candidate genes play a role in functions that are upregulated during cold stress, including protein turnover, metabolism and translation. Our results illustrate how spatially divergent selection spanning the range core to the periphery can occur despite the potential for strong genetic drift at the range edge and moderate gene flow from the core populations.

scholarly journals Constraints on Allele Size at Microsatellite Loci: Implications for Genetic Differentiation

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 1021-1032 ◽  
Author(s):  
Maarten J Nauta ◽  
Franz J Weissing
Keyword(s):  
Genetic Drift ◽  
Time Perspective ◽  
Sequence Data ◽  
Distance Measures ◽  
Population Divergence ◽  
Small Populations ◽  
Random Genetic Drift ◽  
Microsatellite Data ◽  
Mutation Pressure ◽  
History Of

Abstract Microsatellites are promising genetic markers for studying the demographic structure and phylogenetic history of populations. We present theoretical arguments indicating that the usefulness of microsatellite data for these purposes may be limited to a short time perspective and to relatively small populations. The evolution of selectively neutral markers is governed by the interaction of mutation and random genetic drift. Mutation pressure has the inherent tendency to shift different populations to the same distribution of alleles. Hence, mutation pressure is a homogenizing force, and population divergence is caused by random genetic drift. In case of allozymes or sequence data, the diversifying effect of drift is typically orders of magnitude larger than the homogenizing effect of mutation pressure. By a simple model, we demonstrate that the situation may be different for microsatellites where mutation rates are high and the range of alleles is limited. With the help of computer simulations, we investigate to what extent genetic distance measures applied to microsatellite data can nevertheless yield useful estimators for phylogenetic relationships or demographic parameters. We show that predictions based on microsatellite data are quite reliable in small populations, but that already in moderately sized populations the danger of misinterpretation is substantial.

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