scholarly journals Gene flow and natural selection shape spatial patterns of genes in tree populations: implications for evolutionary processes and applications

2015 ◽  
Vol 9 (1) ◽  
pp. 291-310 ◽  
Author(s):  
Victoria L. Sork
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Spatial Patterns ◽  
Evolutionary Processes

Different Spatial Scales of Natural Selection and Gene Flow: The Evolution of Behavioral Geographic Variation and Phenotypic Plasticity

1999 ◽  
Author(s):  
Daniel B. Thompson
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Phenotypic Plasticity ◽  
Spatial Scale ◽  
Geographic Variation ◽  
Genetic Drift ◽  
Spatial Scales ◽  
Environmental Variation ◽  
Behavioral Adaptation ◽  
Evolutionary Processes

The environmental variables hypothesized to cause behavioral adaptation are distributed across a wide array of spatial scales, from local variation in factors such as food sources and territorial encounters to regional or continental variation in factors such as seasonality and the presence of predators. Geographic variation in behavior, the topic of this book, is just one of the potential evolutionary responses to environmental variation. Because behavioral divergence among populations generated by disparate natural selection can be counterbalanced by the homogenizing influence of gene flow, adaptive geographic variation can evolve only if the spatial scale of variation in natural selection is greater than the scale of gene flow (Endler 1977, Slatkin 1978). If geographic variation does not evolve because the spatial scale of selection is smaller than the scale of gene flow, populations may instead evolve adaptive phenotypic plasticity (Bradshaw 1965); the expression, by a single genotype, of different fitness-enhancing phenotypes in different environments. Because the same evolutionary processes operating on different spatial scales can generate behavioral geographic variation, behavioral phenotypic plasticity, or geographic variation in phenotypic plasticity, I devote this chapter to development of a hierarchical perspective tor studying environmental variation and behavioral evolution. This perspective emphasizes the shared evolutionary processes and research methodologies common to different levels of spatial variation, such as the balance of gene flow, natural selection, and genetic drift, the relationship between environmental patch size and local adaptation, and the effects of historical contingencies and genetic constraints on behavioral adaptation and phenotypic plasticity. In what follows, I review behavioral research in two unrelated taxa to illustrate the range of possible evolutionary responses to different patterns of environmental variation. First, I discuss different spatial scales of adaptation in the climbing behavior of deer mice (Peromyscus maniculatus) and provide a hierarchical analysis of the effects of natural selection, genetic drift, and gene flow. Second, I discuss diet-induced phenotypic plasticity in the feeding behavior of acridid grasshoppers (Melanoplus femurrubrum and M. sanguinipes) and the evolution of behavioral norms of reaction in response to local spatial and temporal variation in plant environments.

scholarly journals Modern spandrels: The roles of genetic drift, gene flow and natural selection in the formation of parallel clines

2018 ◽  
Author(s):  
James S. Santangelo ◽  
Marc T. J. Johnson ◽  
Rob W. Ness
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Architecture ◽  
Natural Populations ◽  
Urban Environments ◽  
Phenotypic Change ◽  
Phenotypic Traits ◽  
Evolutionary Processes ◽  
Urbanization Gradients

AbstractUrban environments offer the opportunity to study the role of adaptive and non-adaptive evolutionary processes on an unprecedented scale. While the presence of parallel clines in heritable phenotypic traits is often considered strong evidence for the role of natural selection, non-adaptive evolutionary processes can also generate clines, and this may be more likely when traits have a non-additive genetic basis due to epistasis. In this paper, we use spatially-explicit simulations modelled according to the cyanogenesis (HCN) polymorphism in white clover (Trifolium repens) to examine the formation of phenotypic clines along urbanization gradients under varying levels of drift, gene flow and selection. HCN results from an epistatic interaction between two Mendelian-inherited loci. Our results demonstrate that the genetic architecture of this trait makes natural populations susceptible to decreases in HCN frequencies via drift. Gradients in the strength of drift across a landscape resulted in phenotypic clines with lower frequencies of HCN in strongly drifting populations, giving the misleading appearance of deterministic adaptive changes in the phenotype. Studies of heritable phenotypic change in urban populations should generate null models of phenotypic evolution based on the genetic architecture underlying focal traits prior to invoking selection’s role in generating adaptive differentiation.

scholarly journals Modern spandrels: the roles of genetic drift, gene flow and natural selection in the evolution of parallel clines

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180230 ◽  
Author(s):  
James S. Santangelo ◽  
Marc T. J. Johnson ◽  
Rob W. Ness
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Architecture ◽  
Natural Populations ◽  
Urban Environments ◽  
Phenotypic Change ◽  
Phenotypic Traits ◽  
Evolutionary Processes ◽  
Urbanization Gradients

Urban environments offer the opportunity to study the role of adaptive and non-adaptive evolutionary processes on an unprecedented scale. While the presence of parallel clines in heritable phenotypic traits is often considered strong evidence for the role of natural selection, non-adaptive evolutionary processes can also generate clines, and this may be more likely when traits have a non-additive genetic basis due to epistasis. In this paper, we use spatially explicit simulations modelled according to the cyanogenesis (hydrogen cyanide, HCN) polymorphism in white clover ( Trifolium repens ) to examine the formation of phenotypic clines along urbanization gradients under varying levels of drift, gene flow and selection. HCN results from an epistatic interaction between two Mendelian-inherited loci. Our results demonstrate that the genetic architecture of this trait makes natural populations susceptible to decreases in HCN frequencies via drift. Gradients in the strength of drift across a landscape resulted in phenotypic clines with lower frequencies of HCN in strongly drifting populations, giving the misleading appearance of deterministic adaptive changes in the phenotype. Studies of heritable phenotypic change in urban populations should generate null models of phenotypic evolution based on the genetic architecture underlying focal traits prior to invoking selection's role in generating adaptive differentiation.

scholarly journals Population structure, gene flow and natural selection in populations of Euphydryas phaeton

Heredity ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 407-415 ◽  
Author(s):  
Peter F Brussard ◽  
A Thomas Vawter
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Natural Selection

scholarly journals Dispersal and Differentiation of Deep-Sea Mussels of the GenusBathymodiolus(Mytilidae, Bathymodiolinae)

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Akiko Kyuno ◽  
Mifue Shintaku ◽  
Yuko Fujita ◽  
Hiroto Matsumoto ◽  
Motoo Utsumi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Shallow Water ◽  
Deep Sea ◽  
Dispersal Ability ◽  
Evolutionary Transition ◽  
Significant Genetic Differentiation ◽  
Evolutionary Processes ◽  
High Dispersal ◽  
High Gene

We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes ofBathymodiolusmussels and mytilid relatives. Mussels of the subfamily Bathymodiolinae from vents and seeps belonged to 3 groups and mytilid relatives from sunken wood and whale carcasses assumed the outgroup positions to bathymodioline mussels. Shallow water mytilid mussels were positioned more distantly relative to the vent/seep mussels, indicating an evolutionary transition from shallow to deep sea via sunken wood and whale carcasses.Bathymodiolus platifronsis distributed in the seeps and vents, which are approximately 1500 km away. There was no significant genetic differentiation between the populations. There existed high gene flow betweenB. septemdierumandB. breviorand low but not negligible gene flow betweenB. marisindicusandB. septemdierumorB. brevior, although their habitats are 5000–10 000 km away. These indicate a high adaptability to the abyssal environments and a high dispersal ability ofBathymodiolusmussels.

scholarly journals Natural selection and neutral evolutionary processes contribute to genetic divergence in leaf traits across a precipitation gradient in the tropical oakQuercus oleoides

2018 ◽  
Vol 27 (9) ◽  
pp. 2176-2192 ◽  
Author(s):  
José A. Ramírez-Valiente ◽  
Nicholas J. Deacon ◽  
Julie Etterson ◽  
Alyson Center ◽  
Jed P. Sparks ◽  
...  
Keyword(s):  
Natural Selection ◽  
Genetic Divergence ◽  
Leaf Traits ◽  
Precipitation Gradient ◽  
Evolutionary Processes

scholarly journals Ecological Divergence and the Origins of Intrinsic Postmating Isolation with Gene Flow

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Aneil F. Agrawal ◽  
Jeffrey L. Feder ◽  
Patrik Nosil
Keyword(s):  
Linkage Disequilibrium ◽  
Gene Flow ◽  
Natural Selection ◽  
Theoretical Models ◽  
Ecological Speciation ◽  
Divergent Selection ◽  
Postmating Isolation ◽  
Divergent Natural Selection ◽  
Mathematical Exploration ◽  
Neutral Gene

The evolution of intrinsic postmating isolation has received much attention, both historically and in recent studies of speciation genes. Intrinsic isolation often stems from between-locus genetic incompatibilities, where alleles that function well within species are incompatible with one another when brought together in the genome of a hybrid. It can be difficult for such incompatibilities to originate when populations diverge with gene flow, because deleterious genotypic combinations will be created and then purged by selection. However, it has been argued that if genes underlying incompatibilities are themselves subject to divergent selection, then they might overcome gene flow to diverge between populations, resulting in the origin of incompatibilities. Nonetheless, there has been little explicit mathematical exploration of such scenarios for the origin of intrinsic incompatibilities during ecological speciation with gene flow. Here we explore theoretical models for the origin of intrinsic isolation where genes subject to divergent natural selection also affect intrinsic isolation, either directly or via linkage disequilibrium with other loci. Such genes indeed overcome gene flow, diverge between populations, and thus result in the evolution of intrinsic isolation. We also examine barriers to neutral gene flow. Surprisingly, we find that intrinsic isolation sometimes weakens this barrier, by impeding differentiation via ecologically based divergent selection.

Getting Beyond the Apemen

2021 ◽  
pp. 1-18
Author(s):  
Lesley Newson ◽  
Peter J. Richerson
Keyword(s):  
At Risk ◽  
Natural Selection ◽  
Human Evolution ◽  
Evolutionary Process ◽  
Adult Males ◽  
Evolutionary Processes ◽  
Complex Information ◽  
History Of ◽  
Evolution By Natural Selection

This introductory chapter explains why a new story of human evolution is needed, and also lays the foundations of the story told in this book. One of the reasons we need a new story is that previous stories have concentrated on what our male ancestors were doing. Since survival is most at risk in the first years of life, it makes much more sense to concentrate on children and their mothers than on adult males. A brief account of the history of ideas in evolution by natural selection and human evolution provides readers with a background in evolutionary processes. Humans are a product of evolution, but we are not like other animals, because we are connected and readily share complex information. We are unique and our evolution was the result of a unique evolutionary process. To understand ourselves in evolutionary terms, it’s necessary to consider two intertwined evolutionary processes—genes and culture.

scholarly journals Patterns of Genome-Wide Variation, Population Differentiation and SNP Discovery of the Red Banded Stink Bug (Piezodorus guildinii)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria I. Zucchi ◽  
Erick M. G. Cordeiro ◽  
Clint Allen ◽  
Mariana Novello ◽  
João Paulo Gomes Viana ◽  
...  
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Structure ◽  
Insect Pests ◽  
Geographic Origin ◽  
The United States ◽  
Basic Knowledge ◽  
Stink Bug ◽  
Mixed Ancestry ◽  
Significant Genetic Structure

Abstract Unravelling the details of range expansion and ecological dominance shifts of insect pests has been challenging due to the lack of basic knowledge about population structure, gene flow, and most importantly, how natural selection is affecting the adaptive process. Piezodous guildinii is an emerging pest of soybean in the southern region of the United States, and increasingly important in Brazil in recent years. However, the reasons P. guildinii is gradually becoming more of a problem are questions still mostly unanswered. Here, we have genotyped P. guildinii samples and discovered 1,337 loci containing 4,083 variant sites SNPs that were used to estimate genetic structure and to identify gene candidates under natural selection. Our results revealed the existence of a significant genetic structure separating populations according to their broad geographic origin, i.e., U.S. and Brazil, supported by AMOVA (FGT = 0.26), STRUCTURE, PCA, and FST analyses. High levels of gene flow or coancestry within groups (i.e., within countries) can be inferred from the data, and no spatial pattern was apparent at the finer scale in Brazil. Samples from different seasons show more heterogeneous compositions suggesting mixed ancestry and a more complex dynamic. Lastly, we were able to detect and successfully annotated 123 GBS loci (10.5%) under positive selection. The gene ontology (GO) analysis implicated candidate genes under selection with genome reorganization, neuropeptides, and energy mobilization. We discuss how these findings could be related to recent outbreaks and suggest how new efforts directed to better understand P. guildinii population dynamics.

scholarly journals Host races in plant–feeding insects and their importance in sympatric speciation

2002 ◽  
Vol 357 (1420) ◽  
pp. 471-492 ◽  
Author(s):  
Michele Drès ◽  
James Mallet
Keyword(s):  
Linkage Disequilibrium ◽  
Gene Flow ◽  
Natural Selection ◽  
Reproductive Isolation ◽  
Sympatric Speciation ◽  
Accurate Information ◽  
Sympatric Populations ◽  
New Host ◽  
Host Races ◽  
Plant Feeding

The existence of a continuous array of sympatric biotypes—from polymorphisms, through ecological or host races with increasing reproductive isolation, to good species—can provide strong evidence for a continuous route to sympatric speciation via natural selection. Host races in plant–feeding insects, in particular, have often been used as evidence for the probability of sympatric speciation. Here, we provide verifiable criteria to distinguish host races from other biotypes: in brief, host races are genetically differentiated, sympatric populations of parasites that use different hosts and between which there is appreciable gene flow. We recognize host races as kinds of species that regularly exchange genes with other species at a rate of more than ca . 1% per generation, rather than as fundamentally distinct taxa. Host races provide a convenient, although admittedly somewhat arbitrary intermediate stage along the speciation continuum. They are a heuristic device to aid in evaluating the probability of speciation by natural selection, particularly in sympatry. Speciation is thereby envisaged as having two phases: (i) the evolution of host races from within polymorphic, panmictic populations; and (ii) further reduction of gene flow between host races until the diverging populations can become generally accepted as species. We apply this criterion to 21 putative host race systems. Of these, only three are unambiguously classified as host races, but a further eight are strong candidates that merely lack accurate information on rates of hybridization or gene flow. Thus, over one–half of the cases that we review are probably or certainly host races, under our definition. Our review of the data favours the idea of sympatric speciation via host shift for three major reasons: (i) the evolution of assortative mating as a pleiotropic by–product of adaptation to a new host seems likely, even in cases where mating occurs away from the host; (ii) stable genetic differences in half of the cases attest to the power of natural selection to maintain multilocus polymorphisms with substantial linkage disequilibrium, in spite of probable gene flow; and (iii) this linkage disequilibrium should permit additional host adaptation, leading to further reproductive isolation via pleiotropy, and also provides conditions suitable for adaptive evolution of mate choice (reinforcement) to cause still further reductions in gene flow. Current data are too sparse to rule out a cryptic discontinuity in the apparently stable sympatric route from host–associated polymorphism to host–associated species, but such a hiatus seems unlikely on present evidence. Finally, we discuss applications of an understanding of host races in conservation and in managing adaptation by pests to control strategies, including those involving biological control or transgenic parasite–resistant plants.

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