Gene flow and the geographic structure of natural populations

Science ◽  
1987 ◽  
Vol 236 (4803) ◽  
pp. 787-792 ◽  
Author(s):  
M Slatkin
Keyword(s):  
Gene Flow ◽  
Natural Populations ◽  
Geographic Structure

scholarly journals Genetic structure and gene flow of Eugenia dysenterica natural populations

2005 ◽  
Vol 40 (10) ◽  
pp. 975-980 ◽  
Author(s):  
Maria Imaculada Zucchi ◽  
José Baldin Pinheiro ◽  
Lázaro José Chaves ◽  
Alexandre Siqueira Guedes Coelho ◽  
Mansuêmia Alves Couto ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Variability ◽  
Pearson Correlation ◽  
Natural Populations ◽  
Similarity Index ◽  
Genetic Distances ◽  
Strong Positive Correlation ◽  
Randomly Amplified Polymorphic Dna ◽  
Jaccard Similarity ◽  
Eugenia Dysenterica

This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted and geographic distribution dependent gene flow.

scholarly journals Genome-wide shifts in climate-related variation underpin responses to selective breeding in a widespread conifer

2021 ◽  
Vol 118 (10) ◽  
pp. e2016900118
Author(s):  
Ian R. MacLachlan ◽  
Tegan K. McDonald ◽  
Brandon M. Lind ◽  
Loren H. Rieseberg ◽  
Sam Yeaman ◽  
...  
Keyword(s):  
Gene Flow ◽  
Selective Breeding ◽  
Natural Populations ◽  
Cold Injury ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Differences ◽  
Climatic Regions ◽  
Breeding Populations ◽  
Trade Offs ◽  
Growth Initiation

Locally adapted temperate tree populations exhibit genetic trade-offs among climate-related traits that can be exacerbated by selective breeding and are challenging to manage under climate change. To inform climatically adaptive forest management, we investigated the genetic architecture and impacts of selective breeding on four climate-related traits in 105 natural and 20 selectively bred lodgepole pine populations from western Canada. Growth, cold injury, growth initiation, and growth cessation phenotypes were tested for associations with 18,600 single-nucleotide polymorphisms (SNPs) in natural populations to identify “positive effect alleles” (PEAs). The effects of artificial selection for faster growth on the frequency of PEAs associated with each trait were quantified in breeding populations from different climates. Substantial shifts in PEA proportions and frequencies were observed across many loci after two generations of selective breeding for height, and responses of phenology-associated PEAs differed strongly among climatic regions. Extensive genetic overlap was evident among traits. Alleles most strongly associated with greater height were often associated with greater cold injury and delayed phenology, although it is unclear whether potential trade-offs arose directly from pleiotropy or indirectly via genetic linkage. Modest variation in multilocus PEA frequencies among populations was associated with large phenotypic differences and strong climatic gradients, providing support for assisted gene flow polices. Relationships among genotypes, phenotypes, and climate in natural populations were maintained or strengthened by selective breeding. However, future adaptive phenotypes and assisted gene flow may be compromised if selective breeding further increases the PEA frequencies of SNPs involved in adaptive trade-offs among climate-related traits.

Review Lecture Disruptive selection

1972 ◽  
Vol 182 (1067) ◽  
pp. 109-143 ◽  
Keyword(s):  
Gene Flow ◽  
Genetic Variance ◽  
Natural Populations ◽  
Disruptive Selection ◽  
Ecological Niches ◽  
Gene Exchange ◽  
Bisexual Species ◽  
Frequency Dependent ◽  
Ecological Conditions ◽  
Intermediate Phenotypes

A population is exposed to disruptive selection if more than one phenotype has optimal fitness and intermediate phenotypes have lower fitnesses. Maintenance of the two or more optima may depend upon their relative fitnesses being frequency dependent. Such selection may be expected in two contrasting types of situation. First the two or more optimal phenotypes may depend on one another as do the two sexes in a bisexual species. Secondly the optima may be set by heterogeneity of the environment. Then we may think in terms of a mosaic of ecological niches or a clinal situation, and may expect that gene flow will tend to promote convergence of the sub-populations while disruptive selection tends to promote their divergence. Disruptive selection may therefore be relevant both to the evolution and maintenance of polymorphisms and to the divergence of parts of populations one from another, under the influence of variation of ecological conditions within the range of gametic and/or zygotic dispersal. Disruptive selection has been shown to be capable of increasing phenotypic and genetic variance, of producing and maintaining polymorphisms, of causing divergence of sub-populations between which substantial gene exchange occurs, and of splitting a population into two which are genetically isolated from one another. These results are reviewed and their relevance to natural populations discussed.

scholarly journals SSR Markers for Analysing South American Nothofagus Species

2004 ◽  
Vol 53 (1-6) ◽  
pp. 240-243 ◽  
Author(s):  
M. M. Azpilicueta ◽  
H. Caron ◽  
C. Bodénès ◽  
L. A. Gallo
Keyword(s):  
Gene Flow ◽  
Genetic Mapping ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Natural Populations ◽  
South American ◽  
Sample Sizes ◽  
Polymorphic Ssrs ◽  
The Cross ◽  
Qualitative Confirmation

Summary11 newly discovered microsatellites were used to identify SSR markers for characterising South American Nothofagus species. This was carried out in six species. The sample sizes used were between four and six individuals per species. The cross-genera transferability of 34 Quercus SSRs was also essayed. Out of the 11 new microsatellite markers, three proved to be polymorphic (NnBIO 11, NgBIO 13 and NgBIO 14). The qualitative confirmation of the inheritance of these markers could also be verified. Polymorphism was also observed in five of the cross-genera transferred SSRs (QrBIO7, quru-GA-0A01, quru-GA-0C11, quru-GA-0I01, quru-GA-0M07). The number of alleles per locus found range between 1 and 6 per species. The eight polymorphic SSRs identified in this study will constitute a valuable tool in the gene flow studies that are currently being carried out in natural populations of South American Nothofagus species. The confirmation of crossspecies and cross-genera transferability opens the way for the use of SSRs as bridge markers in genetic mapping.

scholarly journals Outcrossing rates in an experimentally admixed population of self-compatible and self-incompatible Arabidopsis lyrata

Heredity ◽  
2021 ◽  
Author(s):  
Christina Steinecke ◽  
Courtney E. Gorman ◽  
Marc Stift ◽  
Marcel E. Dorken
Keyword(s):  
Gene Flow ◽  
Natural Populations ◽  
Secondary Contact ◽  
Uniform Density ◽  
Evolutionary Divergence ◽  
Arabidopsis Lyrata ◽  
Multiple Origins ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Self Compatibility

AbstractThe transition to self-compatibility from self-incompatibility is often associated with high rates of self-fertilization, which can restrict gene flow among populations and cause reproductive isolation of self-compatible (SC) lineages. Secondary contact between SC and self-incompatible (SI) lineages might re-establish gene flow if SC lineages remain capable of outcrossing. By contrast, intrinsic features of SC plants that reinforce high rates of self-fertilization could maintain evolutionary divergence between lineages. Arabidopsis lyrata subsp. lyrata is characterized by multiple origins of self-compatibility and high rates of self-fertilization in SC-dominated populations. It is unclear whether these high rates of selfing by SC plants have intrinsic or extrinsic causes. We estimated outcrossing rates and examined patterns of pollinator movement for 38 SC and 40 SI maternal parents sampled from an admixed array of 1509 plants sourced from six SC and six SI populations grown under uniform density. Although plants from SI populations had higher outcrossing rates (mean tm = 0.78 ± 0.05 SE) than plants from SC populations (mean tm = 0.56 ± 0.06 SE), outcrossing rates among SC plants were substantially higher than previous estimates from natural populations. Patterns of pollinator movement appeared to contribute to lower outcrossing rates for SC plants; we estimated that 40% of floral visits were geitonogamous (between flowers of the same plant). The relatively high rates of outcrossing for SC plants under standardized conditions indicate that selfing rates in natural SC populations of A. lyrata are facultative and driven by extrinsic features of A. lyrata, including patterns of pollinator movement.

scholarly journals Gene flow and geographic variation in natural populations of Alnus acuminata ssp. arguta (Fagales: Betulaceae) in Costa Rica and Panama

2015 ◽  
pp. 739-753
Author(s):  
Olman Murillo ◽  
Oscar Rocha
Keyword(s):  
Gene Flow ◽  
Costa Rica ◽  
Geographic Variation ◽  
Natural Populations ◽  
Alnus Acuminata

Diecisiete poblaciones naturales de esta especie forestal en Costa Rica y Panamá , fueron investigadas en relación con sus patrones de flujo genético y de variación geográfica. El análisis de flujo genético fue basado en los métodos de los alelo s raros y de FST (Indice de similaridad genética M). Los análisis fueron a su vez basados en los únicos cuatro loci genéticos de un total de 22 investigados que mostraron polimorfismo (POI-B, POM-A, MNR-A and IDH-A). Los análisis de variación geográfica fueron basados en el desarrollo de correlaciones de Pearson entre 4 variables geográficas y 1 4 variables genéticas. Alguna evidencia d e aislamiento por distancia así como un débil flujo genético entre regiones geográficas fue encontrado. Fueron también observados patrones de variación elinal en relación con la altitud (r = -0.62 para la diversidad genética) y latitud (r = -0.77 en POI-B3), que apoyan la hipotesis de aislamiento por distancia para esta especie. No se encontraron a1elos privados en ninguna de las poblaciones investigadas.

scholarly journals Gene flow in natural populations of Brassica species

2002 ◽  
Vol 47 (Supplement) ◽  
pp. 176-177
Author(s):  
T. Kobayashi ◽  
M. Matsuo ◽  
K. Itoh
Keyword(s):  
Gene Flow ◽  
Natural Populations ◽  
Brassica Species

A Comprehensive Study of Genic Variation in Natural Populations of Drosophila melanogaster. I. Estimates of Gene Flow from Rare Alleles

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 313-322
Author(s):  
Rama S Singh ◽  
Lorenz R Rhomberg
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Flow ◽  
West Coast ◽  
Natural Populations ◽  
Evolutionary Significance ◽  
Study Program ◽  
Asian Populations ◽  
Rare Alleles ◽  
Geographic Populations ◽  
Genic Variation

ABSTRACT In order to assess the evolutionary significance of molecular variation in natural populations of Drosophila melanogaster, we have started a comprehensive genetic variation study program employing a relatively large number of gene-protein loci and an array of populations obtained from various geographic locations throughout the world. In this first report we provide estimates of gene flow based on the spatial distributions of rare alleles at 117 gene loci in 15 worldwide populations of D. melanogaster . Estimates of Nm (number of migrants exchanged per generation among populations) range from 1.09 in East-Asian populations (Taiwan, Vietnam and Australia) to 2.66 in West-Coast populations of North America. These estimates, among geographic populations separated by hundreds or even thousands of miles, suggest that gene flow among neighboring populations of D. melanogaster is quite extensive. This means that, for selectively neutral genes, we should expect little differentiation among neighboring populations. A survey of eight West-Coast populations of D. melanogaster (geographically comparable to Drosophila pseudoobscura) showed that in spite of extensive gene flow, populations of D. melanogaster show much more geographic differentiation than comparable populations of D. pseudoobscura. From this we conclude that migration in combination with natural selection rather than migration alone is responsible for the geographic uniformity of molecular polymorphisms in D. pseudoobscura.

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