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

Revista de Biología Tropical ◽

10.15517/rbt.v47i4.19231 ◽

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.

Download Full-text

87:6432 Gene flow and the geographic structure of natural populations

Deep Sea Research Part B Oceanographic Literature Review ◽

10.1016/0198-0254(87)90895-8 ◽

1987 ◽

Vol 34 (11) ◽

pp. 981

Keyword(s):

Gene Flow ◽

Natural Populations ◽

Geographic Structure

Download Full-text

Genetic structure and gene flow of Eugenia dysenterica natural populations

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2005001000005 ◽

2005 ◽

Vol 40 (10) ◽

pp. 975-980 ◽

Cited By ~ 22

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.

Download Full-text

Micro-geographic variation of inversions in natural populations of Drosophila pseudoobscura

Genetika ◽

10.2298/gensr0602097s ◽

2006 ◽

Vol 38 (2) ◽

pp. 97-105 ◽

Cited By ~ 3

Author(s):

Víctor Salceda ◽

José Espinoza-Velazquez

Keyword(s):

Geographic Variation ◽

Population Sample ◽

Polytene Chromosomes ◽

Natural Populations ◽

Chromosomal Polymorphism ◽

Drosophila Pseudoobscura ◽

Natural Habitats ◽

San Luis ◽

San Luis Potosi ◽

San Luis Potosí

Chromosomal polymorphism for the third chromosome in Drosophila pseudoobscura has been widely studied for genetic variation in different environments or locations far apart. However, there is less information regarding sites geographically near one another. Targeting on possible micro-geographic variation in the species, a serial study was done on 12 Mexican populations grouped in four regions, including locations in Durango (DU), the border area of Guanajuato-San Luis Potosi states (GP), Chiapas (CH) and Saldilo (SA). Flies were trapped in their natural habitats using fermenting bananas as bait. They were individually cultivated in the laboratory for larvae production. In a given population sample several flies were cultivated together but only one larva per culture provided salivary tissue to observe polytene chromosomes. Gene arrangements or inversions were identified and frequencies were calculated. A total of 767 third chromosomes were studied and 11 different inversions detected. The type and relative frequencies of the arrangements varied among regions. From the 11 inversions observed, 10 were found in Durango, five in Guanajuato-San Luis Potosi and Chiapas, and eight in Saltillo. The inversion frequencies in the Durango locations varied in four cases, but only one in Chiapas, three cases in Guanajuato-San Luis Potosi, and five in Saltillo. It was also observed that there were geographical gradients for inversions within regions as follows: four arrangements in Saltillo and Durango, three in Guanajuato-San Luis Potos? and one in Chiapas. Moreover, all four regions studied showed evidences for micro-geographical variation. Nevertheless, more studies are needed to elucidate the relevance of the inversion frequencies changes in neighboring populations and also any seasonal-annual frequencies observed in the locations studied here.

Download Full-text

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2016900118 ◽

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.

Download Full-text

Review Lecture Disruptive selection

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1972.0070 ◽

1972 ◽

Vol 182 (1067) ◽

pp. 109-143 ◽

Cited By ~ 66

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.

Download Full-text

Microsatellite DNA Evidence for Gene Flow in Neotropical Lek-Mating Long-Tailed Manakins

The Condor ◽

10.1093/condor/105.3.580 ◽

2003 ◽

Vol 105 (3) ◽

pp. 580-586 ◽

Cited By ~ 3

Author(s):

David B. McDonald

Keyword(s):

Sexual Selection ◽

Gene Flow ◽

Costa Rica ◽

Clustering Analysis ◽

Elevational Gradient ◽

Dna Evidence ◽

Lek Mating ◽

Rapid Divergence ◽

Para Determinar ◽

Single Cluster

Abstract I genotyped lek-mating Long-tailed Manakins (Chiroxiphia linearis) at Monteverde and Santa Rosa, Costa Rica, 115 km apart. Cavalli-Sforza distance was 0.04, DLR was 0.18, and RST and θ were both 0.02. Bayesian clustering analysis indicated that both populations were part of a single cluster rather than from distinct clusters. I present a binomial test for probability of allelic absence as a function of sample size. Genotypic likelihood tests assigned 50% of Monteverde birds to Santa Rosa, versus 26% of Santa Rosa birds to Monteverde. Two lines of evidence supported the idea of asymmetric gene flow up the elevational gradient from Santa Rosa to Monteverde. Low differentiation at this spatial scale, despite intense sexual selection, suggests that sexual selection alone is unlikely to promote rapid divergence leading to speciation. Reduced gene flow, produced by geographic barriers or behavioral factors, may also be required. Evidencia de Flujo Génico Mediante ADN Microsatelital en Chiroxiphia linearis, un Ave Neotropical con Estrategia Reproductiva Tipo “Lek” Resumen. Determiné el genotipo de individuos de Chiroxiphia linearis en dos poblaciones separadas por 115 km, Monteverde y Santa Rosa en Costa Rica. La distancia de Cavalli-Sforza fue 0.04, DLR fue 0.18, y tanto el valor de RST como el de θ fue 0.02. Un análisis de agrupamiento bayesiano indicó que ambas poblaciones pertenecen a un mismo grupo y no a dos grupos diferentes. Presento una prueba binomial para determinar la probabilidad de ausencia alélica como una función del tamaño muestral. La prueba de probabilidad genotípica asignó al 50% de los individuos de Monteverde a la población de Santa Rosa, mientras que un 26% de los individuos de Santa Rosa fue asignado a Monteverde. Dos líneas de evidencia apoyan la idea de flujo génico asimétrico hacia arriba del gradiente altitudinal entre Santa Rosa y Monteverde. A pesar de la intensa presión selectiva sexual, la baja diferenciación a esta escala espacial sugiere que probablemente la selección sexual por sí sola no promueve la rápida divergencia que conduce a la especiación. También se requeriría reducción del flujo génico a través de barreras geográficas y factores conductuales.

Download Full-text