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1.
Mol Biol Rep ; 49(2): 1181-1189, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34981338

RESUMEN

BACKGROUND: Salvia macrosiphon is an aromatic perennial species of Lamiaceae family that grows naturally in different parts of Iran. This herb is widely used in folk and modern medicine. Although in Flora Iranica and Flora of Iran, no infraspecific taxonomic rank has been detected for S. macrosiphon, some infraspecific taxonomic ranks have been reported. In the current study, we evaluated the genetic diversity and structure of 11 populations of this species to detect inter and intrapopulation genetic diversity and to survey the possibility of infraspecific taxonomic ranks in this species. METHODS AND RESULTS: We utilized the modified C-TAB protocol for DNA extraction and amplified the genomes using several SCoT molecular markers. We calculated of genetic diversity and polymorphism parameters using GenAlex 6.4, Geno-Dive ver.2, PopGene, PopART and Structure 2.3.4. The parameters of genetic polymorphism differed between the populations. Moreover, a low rate of gene flow supported a moderate level of population's genetic diversity and differentiation. According to haplotypes network (TCS) analysis, a high level of genetic mutation has occurred among the individuals of some populations leading to high intrapopulation diversity. On the basis of structure analysis and Nei's genetic distance, the examined populations were classified into four genotypes. CONCLUSIONS: The clustering pattern of the populations in each group was not related to geographical distance or phytogeography. It seems that the wide geographic distribution, a small gene flow rate and the occurrence of a high level of genetic mutation lead to infraspecific genetic differentiation in the species and we suppose some infraspecific ranks exist for it.


Asunto(s)
Marcadores Genéticos/genética , Salvia/genética , Clasificación/métodos , Análisis por Conglomerados , Flujo Génico/genética , Variación Genética/genética , Genotipo , Geografía , Irán , Lamiaceae/genética , Repeticiones de Microsatélite/genética , Filogenia , Polimorfismo Genético/genética , Salvia/metabolismo
2.
Genes (Basel) ; 12(8)2021 08 20.
Artículo en Inglés | MEDLINE | ID: mdl-34440453

RESUMEN

A long-standing and unresolved issue in invasion biology concerns the rapid adaptation of invaders to nonindigenous environments. Mikania micrantha is a notorious invasive weed that causes substantial economic losses and negative ecological consequences in southern China. However, the contributions of gene flow, environmental variables, and functional genes, all generally recognized as important factors driving invasive success, to its successful invasion of southern China are not fully understood. Here, we utilized a genotyping-by-sequencing approach to sequence 306 M. micrantha individuals from 21 invasive populations. Based on the obtained genome-wide single nucleotide polymorphism (SNP) data, we observed that all the populations possessed similar high levels of genetic diversity that were not constrained by longitude and latitude. Mikania micrantha was introduced multiple times and subsequently experienced rapid-range expansion with recurrent high gene flow. Using FST outliers, a latent factor mixed model, and the Bayesian method, we identified 38 outlier SNPs associated with environmental variables. The analysis of these outlier SNPs revealed that soil composition, temperature, precipitation, and ecological variables were important determinants affecting the invasive adaptation of M. micrantha. Candidate genes with outlier signatures were related to abiotic stress response. Gene family clustering analysis revealed 683 gene families unique to M. micrantha which may have significant implications for the growth, metabolism, and defense responses of M. micrantha. Forty-one genes showing significant positive selection signatures were identified. These genes mainly function in binding, DNA replication and repair, signature transduction, transcription, and cellular components. Collectively, these findings highlight the contribution of gene flow to the invasion and spread of M. micrantha and indicate the roles of adaptive loci and functional genes in invasive adaptation.


Asunto(s)
Adaptación Fisiológica/genética , Flujo Génico/genética , Mikania/genética , Malezas/genética , China , Especies Introducidas , Metagenómica , Mikania/crecimiento & desarrollo , Malezas/crecimiento & desarrollo
3.
PLoS One ; 16(8): e0255776, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34388195

RESUMEN

The estimation of recent gene flow rates among vast and often weakly genetically differentiated tree populations remains a great challenge. Yet, empirical information would help understanding the interaction between gene flow and local adaptation in present-day non-equilibrium forests. We investigate here recent gene flow rates between two large native Scots pine (Pinus sylvestris L.) populations in central Iberian Peninsula (Spain), which grow on contrasting edaphic conditions six kilometers apart from each other and show substantial quantitative trait divergence in common garden experiments. Using a sample of 1,200 adult and offspring chloroplast-microsatellite haplotypes and a Bayesian inference model, we estimated substantial male gametic gene flow rates (8 and 21%) between the two natural populations, and even greater estimated immigration rates (42 and 64%) from nearby plantations into the two natural populations. Our results suggest that local pollen shedding within large tree populations does not preclude long-distance pollen immigration from large external sources, supporting the role of gene flow as a homogenizing evolutionary force contributing to low molecular genetic differentiation among populations of widely distributed wind-pollinated species. Our results also indicate the high potential for reproductive connectivity in large fragmented populations of wind-pollinated trees, and draw attention to a potential scenario of adaptive genetic divergence in quantitative traits under high gene flow.


Asunto(s)
Flujo Génico/genética , Genética de Población , Pinus sylvestris/genética , Polen/genética , Bosques , Variación Genética/genética , Haplotipos/genética , Polinización/genética , España
4.
Proc Natl Acad Sci U S A ; 118(17)2021 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-33875589

RESUMEN

Wind disperses the pollen and seeds of many plants, but little is known about whether and how it shapes large-scale landscape genetic patterns. We address this question by a synthesis and reanalysis of genetic data from more than 1,900 populations of 97 tree and shrub species around the world, using a newly developed framework for modeling long-term landscape connectivity by wind currents. We show that wind shapes three independent aspects of landscape genetics in plants with wind pollination or seed dispersal: populations linked by stronger winds are more genetically similar, populations linked by directionally imbalanced winds exhibit asymmetric gene flow ratios, and downwind populations have higher genetic diversity. For each of these distinct hypotheses, partial correlations between the respective wind and genetic metrics (controlling for distance and climate) are positive for a significant majority of wind-dispersed or wind-pollinated genetic data sets and increase significantly across functional groups expected to be increasingly influenced by wind. Together, these results indicate that the geography of both wind strength and wind direction play important roles in shaping large-scale genetic patterns across the world's forests. These findings have implications for various aspects of basic plant ecology and evolution, as well as the response of biodiversity to future global change.


Asunto(s)
Flujo Génico/genética , Variación Genética/genética , Árboles/genética , Biodiversidad , Ecosistema , Bosques , Flujo Genético , Genética de Población , Repeticiones de Microsatélite/genética , Polen/genética , Polinización/genética , Dispersión de Semillas/fisiología , Semillas/genética , Árboles/crecimiento & desarrollo , Viento
5.
Sci Rep ; 10(1): 14464, 2020 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-32879340

RESUMEN

The Roma population is a European ethnic minority characterized by recent and multiple dispersals and founder effects. After their origin in South Asia around 1,500 years ago, they migrated West. In Europe, they diverged into ethnolinguistically distinct migrant groups that spread across the continent. Previous genetic studies based on genome-wide data and uniparental markers detected Roma founder events and West-Eurasian gene flow. However, to the best of our knowledge, it has not been assessed whether these demographic processes have equally affected both sexes in the population. The present study uses the largest and most comprehensive dataset of complete mitochondrial and Y chromosome Roma sequences to unravel the sex-biased patterns that have shaped their genetic history. The results show that the Roma maternal genetic pool carries a higher lineage diversity from South Asia, as opposed to a single paternal South Asian lineage. Nonetheless, the European gene flow events mainly occurred through the maternal lineages; however, a signal of this gene flow is also traceable in the paternal lineages. We also detect a higher female migration rate among European Roma groups. Altogether, these results suggest that sociocultural factors influenced the emergence of sex-biased genetic patterns at global and local scales in the Roma population through time.


Asunto(s)
Etnicidad/genética , Genética de Población , Migración Humana , Romaní/genética , Pueblo Asiatico/genética , Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Etnicidad/historia , Femenino , Efecto Fundador , Flujo Génico/genética , Variación Genética/genética , Haplotipos/genética , Historia Antigua , Humanos , Masculino , Caracteres Sexuales , Población Blanca/genética
6.
Cell ; 181(5): 1146-1157.e11, 2020 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-32470400

RESUMEN

We report genome-wide DNA data for 73 individuals from five archaeological sites across the Bronze and Iron Ages Southern Levant. These individuals, who share the "Canaanite" material culture, can be modeled as descending from two sources: (1) earlier local Neolithic populations and (2) populations related to the Chalcolithic Zagros or the Bronze Age Caucasus. The non-local contribution increased over time, as evinced by three outliers who can be modeled as descendants of recent migrants. We show evidence that different "Canaanite" groups genetically resemble each other more than other populations. We find that Levant-related modern populations typically have substantial ancestry coming from populations related to the Chalcolithic Zagros and the Bronze Age Southern Levant. These groups also harbor ancestry from sources we cannot fully model with the available data, highlighting the critical role of post-Bronze-Age migrations into the region over the past 3,000 years.


Asunto(s)
ADN Antiguo/análisis , Etnicidad/genética , Flujo Génico/genética , Arqueología/métodos , ADN Mitocondrial/genética , Etnicidad/historia , Flujo Génico/fisiología , Variación Genética/genética , Genética de Población/métodos , Genoma Humano/genética , Genómica/métodos , Haplotipos , Historia Antigua , Migración Humana/historia , Humanos , Región Mediterránea , Medio Oriente , Análisis de Secuencia de ADN
7.
Cell ; 181(5): 1158-1175.e28, 2020 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-32470401

RESUMEN

Here, we report genome-wide data analyses from 110 ancient Near Eastern individuals spanning the Late Neolithic to Late Bronze Age, a period characterized by intense interregional interactions for the Near East. We find that 6th millennium BCE populations of North/Central Anatolia and the Southern Caucasus shared mixed ancestry on a genetic cline that formed during the Neolithic between Western Anatolia and regions in today's Southern Caucasus/Zagros. During the Late Chalcolithic and/or the Early Bronze Age, more than half of the Northern Levantine gene pool was replaced, while in the rest of Anatolia and the Southern Caucasus, we document genetic continuity with only transient gene flow. Additionally, we reveal a genetically distinct individual within the Late Bronze Age Northern Levant. Overall, our study uncovers multiple scales of population dynamics through time, from extensive admixture during the Neolithic period to long-distance mobility within the globalized societies of the Late Bronze Age. VIDEO ABSTRACT.


Asunto(s)
ADN Antiguo/análisis , Etnicidad/genética , Flujo Génico/genética , Arqueología/métodos , ADN Mitocondrial/genética , Etnicidad/historia , Flujo Génico/fisiología , Variación Genética/genética , Genética de Población/métodos , Genoma Humano/genética , Genómica/métodos , Haplotipos , Historia Antigua , Migración Humana/historia , Humanos , Región Mediterránea , Medio Oriente , Análisis de Secuencia de ADN
8.
Am J Phys Anthropol ; 169(2): 227-239, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30889271

RESUMEN

OBJECTIVES: Modern humans are thought to have interbred with Neanderthals in the Near East soon after modern humans dispersed out of Africa. This introgression event likely took place in either the Levant or southern Arabia depending on the dispersal route out of Africa that was followed. In this study, we compare Neanderthal introgression in contemporary Levantine and southern Arabian populations to investigate Neanderthal introgression and to study Near Eastern population history. MATERIALS AND METHODS: We analyzed genotyping data on >400,000 autosomal SNPs from seven Levantine and five southern Arabian populations and compared these data to those from populations from around the world including Neanderthal and Denisovan genomes. We used f4 and D statistics to estimate and compare levels of Neanderthal introgression between Levantine, southern Arabian, and comparative global populations. We also identified 1,581 putative Neanderthal-introgressed SNPs within our dataset and analyzed their allele frequencies as a means to compare introgression patterns in Levantine and southern Arabian genomes. RESULTS: We find that Levantine and southern Arabian populations have similar levels of Neanderthal introgression to each other but lower levels than other non-Africans. Furthermore, we find that introgressed SNPs have very similar allele frequencies in the Levant and southern Arabia, which indicates that Neanderthal introgression is similarly distributed in Levantine and southern Arabian genomes. DISCUSSION: We infer that the ancestors of contemporary Levantine and southern Arabian populations received Neanderthal introgression prior to separating from each other and that there has been extensive gene flow between these populations.


Asunto(s)
Genética de Población , Migración Humana/historia , Hombre de Neandertal/genética , Animales , Arabia , Flujo Génico/genética , Frecuencia de los Genes/genética , Historia Antigua , Humanos , Medio Oriente , Polimorfismo de Nucleótido Simple/genética
9.
Plant Biol (Stuttg) ; 21(4): 715-722, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30653805

RESUMEN

Pollen viability affects the probability that a pollen grain deposited on a plant's stigma will produce a viable seed. Because a mature seed is needed before a gene flow event can occur, pollen viability will influence the risk of escape for genetically engineered (GE) crops. Pollen viability was measured at intervals for up to 2 h following removal of the pollen from the anthers. It was quantified at three temperatures and for different alfalfa varieties, including both conventional and Roundup Ready (RR) varieties. Pollen viability was assessed using in vitro germination. Time since removal from the anthers was the most prevalent factor affecting pollen viability in alfalfa. Pollen viability declined with increasing time at all three temperatures and for all varieties tested. Pollen viability was not affected by temperatures ranging between 25 and 37 °C and did not vary among plant varieties, including conventional and RR varieties. Bee foraging behaviour suggested pollen viability within the first 10 min following pollen removal from a flower to most affect seed production. Pollen longevity was predicted to have little impact on seed set and gene flow. Linking pollinator behaviour to pollen viability improved our understanding of its impact on gene flow risk.


Asunto(s)
Flujo Génico/genética , Medicago sativa/fisiología , Polen/fisiología , Supervivencia Celular , Flores/fisiología , Germinación , Medicago sativa/genética , Polen/genética , Temperatura , Factores de Tiempo
10.
Mol Biol Rep ; 46(1): 1069-1078, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30556109

RESUMEN

Bitter (Ferula pseudalliacea) and sweet (Ferula assa-foetida) asafetida (Apiaceae family) are well-known economic and medicinal herbs owing to their gum. This study investigates genetic differentiation of F. pseudalliacea and F. assa-foetida using ISSR markers, to determine the effective primer and to assess the possibility of separating sweet and bitter plant populations from each other. Results showed that among 22 primers, eight markers reproduced obvious DNA patterns and revealed 234 scorable DNA bands. ISSR-16 and ISSR-55 primers had better performance than other primers according to the number of bands, PIC and Marker Index. Bitter population showed polymorphic loci (224), percentage of polymorphic loci (95.73%) and observed number of alleles (1.96 ± 0.2), while sweet populations showed the amount of these parameters as 218, 93.16% and 1.93 ± 0.25, respectively. Estimated Gst of sweet population was 0.09 and Gst of bitter population was 0.06. Comparing gene flow in bitter and sweet populations showed a lower level of gene flow between sweet populations (Nm = 4.93) compared to bitter ones (Nm = 7.89). Within group genetic similarity of sweet asafetida population was higher than between group variation of bitter and sweet populations. The highest similarity was observed between bitter populations (0.95). The highest genetic dissimilarity was also estimated between bitter and sweet populations (0.08). Cluster analysis grouped four studied populations into 13 clusters using Jaccard's similarity coefficient and UPGMA method. Principal coordinate analysis showed that 61.02% of total variance was explained using three components and it could completely separate populations as well as cluster analysis. These grouping correspond nearly with geographical distribution. Analysis of molecular variance showed that genetic variation within populations (87%) was more than among populations (13%). The results indicated that ISSR marker is suitable to investigate genetic diversity of asafetida populations and could separate populations of the same genera with similar germplasm.


Asunto(s)
Ferula/genética , Repeticiones de Microsatélite/genética , Técnica del ADN Polimorfo Amplificado Aleatorio/métodos , Alelos , Biomarcadores , Análisis por Conglomerados , Cartilla de ADN , Flujo Génico/genética , Variación Genética/genética , Plantas Medicinales/genética , Polimorfismo Genético/genética
11.
Environ Monit Assess ; 190(12): 744, 2018 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-30470920

RESUMEN

The bark and the latex of plants constitute non-timber forest products (NTFPs) of medicinal and economic value that are widely harvested throughout the world. Bark and latex harvesting impacts on plant reproduction are controversial in the literature. Some species are negatively impacted, some do not show any response, and others may exhibit higher flower and fruit production after harvesting. In areas of rainforests and cerrado (tropical savanna) in northeastern Brazil, local people intensely remove the bark of Himatanthus drasticus (for latex collection) and Stryphnodendron rotundifolium for medicinal purposes. We aimed to investigate the short-term impact of harvesting upon reproductive effort of tree species, using those species as models. We assumed that bark harvesting negatively interferes in the reproductive capacity of plant species. Individuals of both species were harvested 2 months before blooming (treated) and the production of reproductive structures, physical characteristics of fruits and seeds, and the pre-emergent reproductive success were compared between treated and control (intact) individuals. All parameters of H. drasticus declined after bark removal, except pollen and ovule production. The only reproductive parameters of S. rotundifolium that were negatively affected were pollen and ovule production, and the pre-emergent reproductive success was higher in treatment individuals. We discuss the differences found between the species regarding responses to harvesting. Our results show that harvesting have short-term effects upon reproduction and may impair gene flow by affecting pollination and seed dispersal of tree species.


Asunto(s)
Apocynaceae/química , Fabaceae/química , Látex/química , Corteza de la Planta/química , Brasil , Monitoreo del Ambiente , Flores/crecimiento & desarrollo , Bosques , Frutas/crecimiento & desarrollo , Flujo Génico/genética , Humanos , Polen/fisiología , Polinización/fisiología , Semillas/crecimiento & desarrollo , Árboles
12.
Mol Biol Rep ; 45(4): 601-609, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29882084

RESUMEN

Milk thistle (Silybum marianum) is among the world's popular medicinal plants. Start Codon Targeted (SCoT) marker system was utilized to investigate the genetic variability of 80 S. marianum genotypes from eight populations in Iran. SCoT marker produced 255 amplicons and 84.03% polymorphism was generated. The SCoT marker system's polymorphism information content value was 0.43. The primers' resolving power values were between 4.18 and 7.84. The percentage of polymorphic bands was between 33.3 and 100%. The Nei's gene diversity (h) was 0.19-1.30 with an average 0.72. The Shannon's index (I) ranged from 0.29 to 1.38 with an average value of 0.83. The average gene flow (0.37) demonstrated a high genetic variation among the studied populations. The variation of 42% was displayed by the molecular variance analysis among the populations while a recorded variation of 58% was made within the populations. Current investigation suggested that SCoT marker system could effectively evaluate milk thistle genotypes genetic diversity.


Asunto(s)
Marcadores Genéticos/genética , Silybum marianum/genética , Análisis por Conglomerados , Codón Iniciador/genética , Cartilla de ADN , Flujo Génico/genética , Variación Genética/genética , Genética de Población/métodos , Genotipo , Irán , Filogenia , Polimorfismo Genético/genética
13.
Mol Ecol ; 27(15): 3159-3173, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29924880

RESUMEN

Seed and pollen dispersal shape patterns of gene flow and genetic diversity in plants. Pollen is generally thought to travel longer distances than seeds, but seeds determine the ultimate location of gametes. Resolving how interactions between these two dispersal processes shape microevolutionary processes is a long-standing research priority. We unambiguously isolated the separate and combined contributions of these two dispersal processes in seedlings of the animal-dispersed palm Oenocarpus bataua to address two questions. First, what is the spatial extent of pollen versus seed movement in a system characterized by long-distance seed dispersal? Second, how does seed dispersal mediate seedling genetic diversity? Despite evidence of frequent long-distance seed dispersal, we found that pollen moves much further than seeds. Nonetheless, seed dispersal ultimately mediates genetic diversity and fine-scale spatial genetic structure. Compared to undispersed seedlings, seedlings dispersed by vertebrates were characterized by higher female gametic and diploid seedling diversity and weaker fine-scale spatial genetic structure for female gametes, male gametes and diploid seedlings. Interestingly, the diversity of maternal seed sources at seed deposition sites (Nem ) was associated with higher effective number of pollen sources (Nep ), higher effective number of parents (Ne ) and weaker spatial genetic structure, whereas seed dispersal distance had little impact on these or other parameters we measured. These findings highlight the importance maternal seed source diversity (Nem ) at frugivore seed deposition sites in driving emergent patterns of fine-scale genetic diversity and structure.


Asunto(s)
Arecaceae/genética , Flujo Génico/genética , Plantones/genética , Semillas/genética , Arecaceae/fisiología , Genética de Población , Repeticiones de Microsatélite/genética , Polen/genética , Polen/fisiología , Dispersión de Semillas/genética , Dispersión de Semillas/fisiología , Plantones/fisiología , Semillas/fisiología
14.
Nature ; 551(7680): 368-372, 2017 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-29144465

RESUMEN

Ancient DNA studies have established that Neolithic European populations were descended from Anatolian migrants who received a limited amount of admixture from resident hunter-gatherers. Many open questions remain, however, about the spatial and temporal dynamics of population interactions and admixture during the Neolithic period. Here we investigate the population dynamics of Neolithization across Europe using a high-resolution genome-wide ancient DNA dataset with a total of 180 samples, of which 130 are newly reported here, from the Neolithic and Chalcolithic periods of Hungary (6000-2900 bc, n = 100), Germany (5500-3000 bc, n = 42) and Spain (5500-2200 bc, n = 38). We find that genetic diversity was shaped predominantly by local processes, with varied sources and proportions of hunter-gatherer ancestry among the three regions and through time. Admixture between groups with different ancestry profiles was pervasive and resulted in observable population transformation across almost all cultural transitions. Our results shed new light on the ways in which gene flow reshaped European populations throughout the Neolithic period and demonstrate the potential of time-series-based sampling and modelling approaches to elucidate multiple dimensions of historical population interactions.


Asunto(s)
Agricultores/historia , Flujo Génico/genética , Variación Genética , Migración Humana/historia , ADN Antiguo/análisis , Conjuntos de Datos como Asunto , Femenino , Alemania , Historia Antigua , Humanos , Hungría , Masculino , Dinámica Poblacional , España , Análisis Espacio-Temporal
15.
Ann Bot ; 119(4): 671-679, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28028015

RESUMEN

Background and Aims: Wild olive ( Olea europaea subsp. europaea var. sylvestris ) is important from an economic and ecological point of view. The effects of anthropogenic activities may lead to the genetic erosion of its genetic patrimony, which has high value for breeding programmes. In particular, the consequences of the introgression from cultivated stands are strongly dependent on the extent of gene flow and therefore this work aims at quantitatively describing contemporary gene flow patterns in wild olive natural populations. Methods: The studied wild population is located in an undisturbed forest, in southern Spain, considered one of the few extant hotspots of true oleaster diversity. A total of 225 potential father trees and seeds issued from five mother trees were genotyped by eight microsatellite markers. Levels of contemporary pollen flow, in terms of both pollen immigration rates and within-population dynamics, were measured through paternity analyses. Moreover, the extent of fine-scale spatial genetic structure (SGS) was studied to assess the relative importance of seed and pollen dispersal in shaping the spatial distribution of genetic variation. Key Results: The results showed that the population under study is characterized by a high genetic diversity, a relatively high pollen immigration rate (0·57), an average within-population pollen dispersal of about 107 m and weak but significant SGS up to 40 m. The population is a mosaic of several intermingled genetic clusters that is likely to be generated by spatially restricted seed dispersal. Moreover, wild oleasters were found to be self-incompatible and preferential mating between some genotypes was revealed. Conclusions: Knowledge of the within-population genetic structure and gene flow dynamics will lead to identifying possible strategies aimed at limiting the effect of anthropogenic activities and improving breeding programmes for the conservation of olive tree forest genetic resources.


Asunto(s)
Flujo Génico/genética , Olea/genética , Polen/genética , Variación Genética/genética , Genética de Población , España
16.
Am J Hum Genet ; 99(6): 1316-1324, 2016 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-27889059

RESUMEN

Understanding human genetic diversity in Africa is important for interpreting the evolution of all humans, yet vast regions in Africa, such as Chad, remain genetically poorly investigated. Here, we use genotype data from 480 samples from Chad, the Near East, and southern Europe, as well as whole-genome sequencing from 19 of them, to show that many populations today derive their genomes from ancient African-Eurasian admixtures. We found evidence of early Eurasian backflow to Africa in people speaking the unclassified isolate Laal language in southern Chad and estimate from linkage-disequilibrium decay that this occurred 4,750-7,200 years ago. It brought to Africa a Y chromosome lineage (R1b-V88) whose closest relatives are widespread in present-day Eurasia; we estimate from sequence data that the Chad R1b-V88 Y chromosomes coalesced 5,700-7,300 years ago. This migration could thus have originated among Near Eastern farmers during the African Humid Period. We also found that the previously documented Eurasian backflow into Africa, which occurred ∼3,000 years ago and was thought to be mostly limited to East Africa, had a more westward impact affecting populations in northern Chad, such as the Toubou, who have 20%-30% Eurasian ancestry today. We observed a decline in heterozygosity in admixed Africans and found that the Eurasian admixture can bias inferences on their coalescent history and confound genetic signals from adaptation and archaic introgression.


Asunto(s)
Variación Genética/genética , Migración Humana/historia , Animales , Asia/etnología , Chad , Etiopía , Europa (Continente)/etnología , Flujo Génico/genética , Genética de Población , Genoma Humano/genética , Heterocigoto , Historia Antigua , Humanos , Desequilibrio de Ligamiento , Medio Oriente , Hombre de Neandertal/genética , Polimorfismo de Nucleótido Simple/genética , Densidad de Población
17.
Mol Phylogenet Evol ; 97: 155-169, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26785110

RESUMEN

Southern Iberian freshwater ecosystems located at the border between the European and African plates represent a tectonically complex region spanning several geological ages, from the uplifting of the Betic Mountains in the Serravalian-Tortonian periods to the present. This area has also been subjected to the influence of changing climate conditions since the Middle-Upper Pliocene when seasonal weather patterns were established. Consequently, the ichthyofauna of southern Iberia is an interesting model system for analyzing the influence of Cenozoic tectonic and climatic events on its evolutionary history. The cyprinids Squalius malacitanus and Squalius pyrenaicus are allopatrically distributed in southern Iberia and their evolutionary history may have been defined by Cenozoic tectonic and climatic events. We analyzed MT-CYB (510 specimens) and RAG1 (140 specimens) genes of both species to reconstruct phylogenetic relationships and to estimate divergence times and ancestral distribution ranges of the species and their populations. We also assessed their levels of genetic structure and diversity as well as the amount of gene flow between populations. To investigate recent paleogeographical and climatic factors in southern Iberia, we modeled changes-through-time in sea level from the LGM to the present. Phylogenetic, geographic and population structure analyses revealed two well-supported species (S. malacitanus and S. pyrenaicus) in southern Iberia and two subclades (Atlantic and Mediterranean) within S. malacitanus. The origin of S. malacitanus and the separation of its Atlantic and Mediterranean populations occurred during the Serravalian-Tortonian and Miocene-Pliocene periods, respectively. These divergence events occurred in the Middle Pliocene and Pleistocene in S. pyrenaicus. In both species, Atlantic basins possessed populations with higher genetic diversity than Mediterranean, which may be explained by the Janda Lagoon. The isolation of S. malacitanus was earlier and related to the rising of the Betic Mountains. Divergence of its Atlantic and Mediterranean populations was associated with the creation of the freshwater systems of southern Iberia close to the Gibraltar Strait. The presence of S. pyrenaicus in southern Iberia may be the result of recent colonization associated with river capture, as demonstrated our biogeographic reconstruction.


Asunto(s)
Clima , Cyprinidae/genética , Ecosistema , Agua Dulce , Filogenia , Animales , Océano Atlántico , Evolución Molecular , Flujo Génico/genética , Genes Mitocondriales/genética , Variación Genética , Historia Antigua , Mar Mediterráneo , Filogeografía , Ríos , España
18.
J Hered ; 106(1): 93-101, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25472982

RESUMEN

Encholirium horridum is a bromeliad that occurs exclusively on inselbergs in the Atlantic Forest biome of Brazil. These rock outcrops form natural islands that isolate populations from each other. We investigated gene flow by pollen through paternity analyses of a bromeliad population in an area of approximately 2 ha in Espírito Santo State, Brazil. To that end, seed rosettes and seedlings were genotyped using nuclear microsatellite loci. A plot was also established from the same population and specimens were genotyped to evaluate their fine-scale spatial genetic structure (SGS) through analyses of spatial autocorrelation and clonal growth. Paternity analysis indicated that 80% of the attributed progenitors of the genotyped seedlings were from inside the study area. The pollen dispersal distances within the area were restricted (mean distance of 45.5 m, varying from 3 to 156 m) and fine-scale SGS was weak (F(ij) = 0.0122, P < 0.001; Sp = 0.009). Clonal growth was found to be a rare event, supporting the monocarpy of this species.


Asunto(s)
Bromeliaceae/genética , Demografía , Especies en Peligro de Extinción , Flujo Génico/genética , Variación Genética , Dispersión de Semillas/fisiología , Brasil , Bromeliaceae/crecimiento & desarrollo , Bosques , Genética de Población , Genotipo , Repeticiones de Microsatélite/genética , Polen/genética , Dispersión de Semillas/genética
19.
Transgenic Res ; 23(5): 795-807, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24962816

RESUMEN

Because of the rapid development of transgenic maize, the potential effect of transgene flow on seed purity has become a major concern in public and scientific communities. Setting a proper isolation distance in field experiments and seed production is a possible solution to meet seed-quality standards and ensure adventitious contamination of products is below a specific threshold. By using a Gaussian plume model as basis and data recorded by meteorological stations as input, we have established a simple regionally applicable maize gene-flow model for prediction of the maximum threshold distances (MTD) at which gene-flow frequency is equal to or lower than a threshold value of 1 or 0.1 % (MTD1%, MTD0.1%). After optimization of the model variables, simulated outcrossing rate was a good fit to data obtained from field experiments (y = 1.156x, R (2) = 0.8913, n = 30, P < P 0.01). In the process of model calibration, it was found that only 15.82 % of the total amount of the pollen released by each plant participated in the dispersal process. The variable "a" for genetic pollen competitiveness between donor and recipient was introduced into our model, for the "Zinuo18" and "Su608" used, "a" was 17.47. Finally, the model was successfully used in the spring maize-growing region of Northeast China. The range of MTD1% and MTD0.1% in this region varied from 10 m to 49 m and from 17 m to 125 m, respectively.


Asunto(s)
Agricultura/métodos , Flujo Génico/genética , Modelos Genéticos , Plantas Modificadas Genéticamente/genética , Semillas/genética , Zea mays/genética , China , Genética de Población , Polen/genética , Análisis de Regresión , Dispersión de Semillas/genética
20.
Heredity (Edinb) ; 113(3): 215-23, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24619186

RESUMEN

The genetic diversity of small populations is greatly influenced by local dispersal patterns and genetic connectivity among populations, with pollen dispersal being the major component of gene flow in many plants species. Patterns of pollen dispersal, mating system parameters and spatial genetic structure were investigated in a small isolated population of the emblematic palm Phoenix canariensis in Gran Canaria island (Canary Islands). All adult palms present in the study population (n=182), as well as 616 seeds collected from 22 female palms, were mapped and genotyped at 8 microsatellite loci. Mating system analysis revealed an average of 5.8 effective pollen donors (Nep) per female. There was strong variation in correlated paternity rates across maternal progenies (ranging from null to 0.9) that could not be explained by the location and density of local males around focal females. Paternity analysis revealed a mean effective pollen dispersal distance of ∼71 m, with ∼70% of effective pollen originating from a distance of <75 m, and 90% from <200 m. A spatially explicit mating model indicated a leptokurtic pollen dispersal kernel, significant pollen immigration (12%) from external palm groves and a directional pollen dispersal pattern that seems consistent with local altitudinal air movement. No evidence of inbreeding or genetic diversity erosion was found, but spatial genetic structure was detected in the small palm population. Overall, the results suggest substantial pollen dispersal over the studied population, genetic connectivity among different palm groves and some resilience to neutral genetic erosion and subsequently to fragmentation.


Asunto(s)
Arecaceae/genética , Polen/genética , Polinización/genética , Flujo Génico/genética , Estructuras Genéticas/genética , Variación Genética/genética , Genotipo , Reproducción/genética , Semillas/genética , España
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