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Kang S, Kim S, Park KC, Petrašiūnas A, Shin HC, Jo E, Cho SM, Kim JH. Molecular evidence for multiple origins and high genetic differentiation of non-native winter crane fly, Trichocera maculipennis (Diptera: Trichoceridae), in the maritime Antarctic. ENVIRONMENTAL RESEARCH 2024; 242:117636. [PMID: 37952853 DOI: 10.1016/j.envres.2023.117636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/14/2023]
Abstract
Native biodiversity and ecosystems of Antarctica safeguarded from biological invasion face recent threats from non-native species, accelerated by increasing human activities and climate changes. Over two decades ago, the winter crane fly, Trichocera maculipennis, was first detected on King George Island. It has now successfully colonized several research stations across King George Island. To understand the origin, genetic diversity, and population structure of this Holarctic species, we conducted mitochondrial DNA cytochrome c oxidase subunit I (COI) sequence analysis across both its native and invasive ranges. In parallel, we performed microsatellite loci analysis within the invasive ranges, utilizing 12 polymorphic microsatellite markers. Furthermore, we compared body sizes among adult males and females collected from three different locations of King George Island. Our COI sequence analysis exhibited two different lineages present on King George Island. Lineage I was linked to Arctic Svalbard and Polish cave populations and Lineage II was related to Canadian Terra Nova National Park populations, implying multiple origins. Microsatellite analysis further exhibited high levels of genetic diversity and significant levels of genetic differentiation among invasive populations. Body sizes of adult T. maculipennis were significantly different among invasive populations but were not attributed to genetics. This significant genetic diversity likely facilitated the rapid colonization and establishment of T. maculipennis on King George Island, contributing to their successful invasion. Molecular analysis results revealed a substantial amount of genetic variation within invasive populations, which can serve as management units for invasive species control. Furthermore, the genetic markers we developed in the study will be invaluable tools for tracking impending invasion events and the travel routes of new individuals. Taken together, these findings illustrate the highly invasive and adaptable characteristics of T. maculipennis. Therefore, immediate action is necessary to mitigate their ongoing invasion and facilitate their eradication.
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Affiliation(s)
- Seunghyun Kang
- Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Sanghee Kim
- Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Kye Chung Park
- The New Zealand Institute for Plant and Food Research Ltd., Christchurch, 8140, New Zealand
| | - Andrius Petrašiūnas
- Department of Zoology, Institute of Biosciences, Vilnius University Life Sciences Center, LT 1022, Vilnius, Lithuania
| | | | - Euna Jo
- Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Sung Mi Cho
- Korea Polar Research Institute, Incheon, 21990, South Korea
| | - Ji Hee Kim
- Korea Polar Research Institute, Incheon, 21990, South Korea.
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Lewis EM, Fant JB, Moore MJ, Skogen KA. Hawkmoth and bee pollinators impact pollen dispersal at the landscape but not local scales in two species of Oenothera. AMERICAN JOURNAL OF BOTANY 2023:e16156. [PMID: 36934437 DOI: 10.1002/ajb2.16156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
PREMISE Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth). METHODS We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60-440 km; five populations) scales using 10-11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers. RESULTS Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species. CONCLUSIONS We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.
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Affiliation(s)
- Emily M Lewis
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
| | - Jeremie B Fant
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, 60022, USA
| | - Michael J Moore
- Biology Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Krissa A Skogen
- Northwestern University, Program in Plant Biology and Conservation, Evanston, IL, 60201, USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, 60022, USA
- Department of Biological Sciences, Clemson University, Clemson, SC, 29634, USA
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Sengupta A, Dayanandan S. Biodiversity of India: Evolution, biogeography, and conservation. Biotropica 2022. [DOI: 10.1111/btp.13168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Asmita Sengupta
- Ashoka Trust for Research in Ecology and the Environment Bangalore India
- National Institute of Advanced Studies Indian Institute of Science Campus Bangalore India
| | - Selvadurai Dayanandan
- Department of Biology and Centre for Structural & Functional Genomics Concordia University Montreal Quebec Canada
- Quebec Centre for Biodiversity Science Montreal Quebec Canada
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Li D, Li M, Li F, Weng Q, Zhou C, Huang S, Gan S. Transcriptome-derived microsatellite markers for population diversity analysis in Archidendron clypearia (Jack) I.C. Nielsen. Mol Biol Rep 2021; 48:8255-8260. [PMID: 34655020 DOI: 10.1007/s11033-021-06773-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/17/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND The medicinal woody leguminous genus Archidendron F. Mueller serves as important herbal resources for curing upper respiratory tract infection, acute pharyngitis, tonsillitis, and gastroenteritis. However, genomic resources including transcriptomic sequences and molecular markers remain scarce in the genus. METHODS AND RESULTS Transcriptome sequencing, genic microsatellite marker development, and population diversity analysis were conducted in Archidendron clypearia (Jack) I.C. Nielsen. Flower and flower bud transcriptomes were de novo assembled into 173,172 transcripts, with an average transcript length of 1597.3 bp and an N50 length of 2427 bp. A total of 34,701 microsatellite loci were identified from 26,716 (15.4 %) transcripts. Primer pairs were designed for 718 microsatellite loci, of which 456 (63.5 %) were polymorphic. Of the 456 polymorphic markers, 391 (85.7 %) and 402 (88.1 %) were transferable to A. lucidum (Benth.) I.C. Nielsen and A. multifoliolatum (H.Q. Wen) T.L. Wu, respectively. Using a subset of 15 microsatellite markers, relatively high genetic diversity was detected over two A. clypearia populations, with overall mean expected heterozygosity (He) being 0.707 and demonstrating the necessity of conservation. Relatively low differentiation between the two populations was revealed despite the distant separation (about 700 km), with overall inbreeding coefficient of sub-population to the total population (Fst) being 8.7 %. CONCLUSIONS This study represents the first attempt to conduct transcriptome sequencing, SSR marker development, and population genetics analysis in the medicinally important genus Archidendron. Our results will offer valuable resources and information for further genetic studies and practical applications in Archidendron and the related taxa.
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Affiliation(s)
- Dandan Li
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Xiangshan Road, Beijing, 100091, China
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Mei Li
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Fagen Li
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Qijie Weng
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Changpin Zhou
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Shineng Huang
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China
| | - Siming Gan
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Xiangshan Road, Beijing, 100091, China.
- Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Yi Road, Guangzhou, 510520, Guangdong, China.
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Honorio Coronado EN, Dexter KG, Hart ML, Phillips OL, Pennington RT. Comparative phylogeography of five widespread tree species: Insights into the history of western Amazonia. Ecol Evol 2019; 9:7333-7345. [PMID: 31380054 PMCID: PMC6662334 DOI: 10.1002/ece3.5306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/20/2019] [Accepted: 05/04/2019] [Indexed: 11/26/2022] Open
Abstract
Various historical processes have been put forth as drivers of patterns in the spatial distribution of Amazonian trees and their population genetic variation. We tested whether five widespread tree species show congruent phylogeographic breaks and similar patterns of demographic expansion, which could be related to proposed Pleistocene refugia or the presence of geological arches in western Amazonia. We sampled Otoba parvifolia/glycycarpa (Myristicaceae), Clarisia biflora, Poulsenia armata, Ficus insipida (all Moraceae), and Jacaratia digitata (Caricaceae) across the western Amazon Basin. Plastid DNA (trnH-psbA; 674 individuals from 34 populations) and nuclear ribosomal internal transcribed spacers (ITS; 214 individuals from 30 populations) were sequenced to assess genetic diversity, genetic differentiation, population genetic structure, and demographic patterns. Overall genetic diversity for both markers varied among species, with higher values in populations of shade-tolerant species than in pioneer species. Spatial analysis of molecular variance (SAMOVA) identified three genetically differentiated groups for the plastid marker for each species, but the areas of genetic differentiation were not concordant among species. Fewer SAMOVA groups were found for ITS, with no detectable genetic differentiation among populations in pioneers. The lack of spatially congruent phylogeographic breaks across species suggests no common biogeographic history of these Amazonian tree species. The idiosyncratic phylogeographic patterns of species could be due instead to species-specific responses to geological and climatic changes. Population genetic patterns were similar among species with similar biological features, indicating that the ecological characteristics of species impact large-scale phylogeography.
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Affiliation(s)
| | - Kyle G. Dexter
- School of GeoSciencesUniversity of EdinburghEdinburghUK
- Royal Botanic Garden EdinburghEdinburghUK
| | | | | | - R. Toby Pennington
- Royal Botanic Garden EdinburghEdinburghUK
- Department of GeographyUniversity of ExeterExeterUK
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Zhang LJ, Lou AR. Patterns of Pollen Dispersal in an Invasive Population of Solanum rostratum (Solanaceae) in China. RUSS J ECOL+ 2019. [DOI: 10.1134/s1067413618660050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Short-distance pollen dispersal by bats in an urban setting: monitoring the movement of a vertebrate pollinator through fluorescent dyes. Urban Ecosyst 2019. [DOI: 10.1007/s11252-019-0825-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Leo SST, Gonzalez A, Millien V. The Genetic Signature of Range Expansion in a Disease Vector-The Black-Legged Tick. J Hered 2018; 108:176-183. [PMID: 28173203 DOI: 10.1093/jhered/esw073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 10/06/2016] [Indexed: 12/23/2022] Open
Abstract
Monitoring and predicting the spread of emerging infectious diseases requires that we understand the mechanisms of range expansion by its vectors. Here, we examined spatial and temporal variation of genetic structure among 13 populations of the Lyme disease vector, the black-legged tick, in southern Quebec, where this tick species is currently expanding and Lyme disease is emerging. Our objective was to identify the primary mode of tick movement into Canada based on observed spatial and temporal genetic patterns. Upon genotyping 10 microsatellite loci from 613 tick specimens, we found multiple genetic signatures of frequent long-distance dispersal events, supporting the hypothesis that migratory birds are the primary carriers of black-legged ticks into southern Quebec. When we compared results from analyses of pairwise differences among ticks collected from 8 different sites at different years between 2011 and 2014, we found that genetic variation observed among tick individuals appeared to be better explained by collection year than sampling locality. This suggests that while cohorts of black-legged ticks can rapidly invade large areas across southern Quebec, they also appear to be undergoing frequent turnover. Finally, the amount of genetic variation in tick populations across our study area appeared to be related to their degree of establishment, with established populations displaying a lower amount of temporal genetic variation than adventitious ones. Given that Lyme disease infection risk in a region can be influenced by the relative presence of established and/or adventitious tick populations, our results are useful for understanding both the seasonality and spatial variation of Lyme disease.
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Affiliation(s)
- Sarah S T Leo
- Department of Biology, McGill University, Montreal, Quebec, Canada.,Redpath Museum, McGill University, Montreal, Quebec, Canada
| | - Andrew Gonzalez
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Warner PA, Willis BL, Oppen MJH. Sperm dispersal distances estimated by parentage analysis in a brooding scleractinian coral. Mol Ecol 2016; 25:1398-415. [DOI: 10.1111/mec.13553] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/27/2015] [Accepted: 01/04/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Patricia A. Warner
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- College of Marine and Environmental Sciences James Cook University Townsville Qld 4811 Australia
| | - Bette L. Willis
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- College of Marine and Environmental Sciences James Cook University Townsville Qld 4811 Australia
| | - Madeleine J. H. Oppen
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Australian Institute of Marine Science PMB3, Townsville MC Townsville Qld 4810 Australia
- School of BioSciences The University of Melbourne Parkville Vic. 23010 Australia
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Preliminary Genomic Characterization of Ten Hardwood Tree Species from Multiplexed Low Coverage Whole Genome Sequencing. PLoS One 2015; 10:e0145031. [PMID: 26698853 PMCID: PMC4689444 DOI: 10.1371/journal.pone.0145031] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 11/27/2015] [Indexed: 11/19/2022] Open
Abstract
Forest health issues are on the rise in the United States, resulting from introduction of alien pests and diseases, coupled with abiotic stresses related to climate change. Increasingly, forest scientists are finding genetic/genomic resources valuable in addressing forest health issues. For a set of ten ecologically and economically important native hardwood tree species representing a broad phylogenetic spectrum, we used low coverage whole genome sequencing from multiplex Illumina paired ends to economically profile their genomic content. For six species, the genome content was further analyzed by flow cytometry in order to determine the nuclear genome size. Sequencing yielded a depth of 0.8X to 7.5X, from which in silico analysis yielded preliminary estimates of gene and repetitive sequence content in the genome for each species. Thousands of genomic SSRs were identified, with a clear predisposition toward dinucleotide repeats and AT-rich repeat motifs. Flanking primers were designed for SSR loci for all ten species, ranging from 891 loci in sugar maple to 18,167 in redbay. In summary, we have demonstrated that useful preliminary genome information including repeat content, gene content and useful SSR markers can be obtained at low cost and time input from a single lane of Illumina multiplex sequence.
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Tambarussi EV, Boshier D, Vencovsky R, Freitas MLM, Sebbenn AM. Paternity analysis reveals significant isolation and near neighbor pollen dispersal in small Cariniana legalis Mart. Kuntze populations in the Brazilian Atlantic Forest. Ecol Evol 2015; 5:5588-600. [PMID: 27069608 PMCID: PMC4813111 DOI: 10.1002/ece3.1816] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 11/09/2022] Open
Abstract
Throughout the world, large trees are increasingly rare. Cariniana legalis is the tallest tree species of the Brazilian Atlantic Forest, reaching up to 60 m in height. Due to extensive deforestation of the Atlantic Forest, remnant C. legalis populations are small and spatially isolated, requiring the development of strategies for their conservation. For in situ and ex situ genetic conservation to be effective, it is important to understand the levels and patterns of spatial genetic structure (SGS), and gene flow. We investigated SGS and pollen flow in three small, physically isolated C. legalis stands using microsatellite loci. We measured, mapped, and sampled all C. legalis trees in the three stands: 65 trees from Ibicatu population, 22 trees from MGI, and 4 trees from MGII. We also collected and genotyped 600 seeds from Ibicatu, 250 seeds from MGI, and 200 seeds from MGII. Significant SGS was detected in Ibicatu up to 150 m, but substantial levels of external pollen flow were also detected in Ibicatu (8%), although not in MGI (0.4%) or MGII (0%). Selfing was highest in MGII (18%), the smallest group of trees, compared to MGI (6.4%) and Ibicatu (6%). In MGI and MGII, there was a strong pattern of mating among near‐neighbors. Seed collection strategies for breeding, in situ and ex situ conservation and ecological restoration, must ensure collection from seed trees located at distances greater than 350 m and from several forest fragments.
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Affiliation(s)
- Evandro V Tambarussi
- Escola Superior de Agricultura "Luiz de Queiroz" Universidade de São Paulo Av. Pádua Dias, 11 Caixa Postal 9 Piracicaba 13418-900 Brazil
| | - David Boshier
- Department of Plant Sciences South Parks Road Oxford OX1 3RB UK
| | - Roland Vencovsky
- Escola Superior de Agricultura "Luiz de Queiroz" Universidade de São Paulo Av. Pádua Dias, 11 Caixa Postal 9 Piracicaba 13418-900 Brazil
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Kang S, Jung J, Kim W. Population Genetic Structure of the Malaria Vector Anopheles sinensis (Diptera: Culicidae) Sensu Stricto and Evidence for Possible Introgression in the Republic of Korea. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:1270-1281. [PMID: 26336253 DOI: 10.1093/jme/tjv114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/17/2015] [Indexed: 06/05/2023]
Abstract
Anopheles sinensis Wiedemann sensu stricto (s.s.) is a dominant mosquito and considered a secondary malaria vector in the Republic of Korea (ROK). Despite the potential significance for malaria control, population genetics studies have been conducted using only mitochondrial DNA (mtDNA), and studies of the genetics of hybridization have never been attempted. In this study, 346 specimens from 23 localities were subject to experiments. Among them, 305 An. sinensis s.s. specimens from 20 localities were used for mtDNA analysis, and 346 specimens comprising 341 An. sinensis s.s. from 22 localities and five Anopheles kleini Rueda from one locality were examined in the microsatellite study. Neighbor-joining analysis of pairwise FST and RST based on microsatellite results showed that the populations are divided into two groups, as did the mtDNA results. However, the Bayesian analysis and factorial correspondence analysis plots showed three distinct clusters. Among the mtDNA and microsatellite results, only microsatellites represented small but positive and significant isolation-by-distance patterns. Both molecular markers show the Taebaek and Sobaek Mountain ranges as barriers between the northern and southern parts of the ROK. The newly recognized third group suggests possible introgressive hybridization of An. sinensis s.s. with closely related species. The slightly different composition of populations in each group based on different markers is probably because of different population dynamics in each group. These results imply that there is restricted gene flow of epidemiologically important malaria-related genes between the northern and southern parts of the ROK.
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Affiliation(s)
- Seunghyun Kang
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 406-840, Republic of Korea
| | - Jongwoo Jung
- Department of Science Education, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Republic of Korea
| | - Won Kim
- School of Biological Sciences, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
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Finger A, Kaiser-Bunbury CN, Kettle CJ, Valentin T, Ghazoul J. Genetic connectivity of the moth pollinated tree Glionnetia sericea in a highly fragmented habitat. PLoS One 2014; 9:e111111. [PMID: 25347541 PMCID: PMC4210268 DOI: 10.1371/journal.pone.0111111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 09/23/2014] [Indexed: 11/20/2022] Open
Abstract
Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow.
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Affiliation(s)
- Aline Finger
- Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- * E-mail:
| | | | - Chris J. Kettle
- Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | | | - Jaboury Ghazoul
- Environmental Systems Science, ETH Zürich, Zürich, Switzerland
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Genetic differentiation and species cohesion in two widespread Central American Begonia species. Heredity (Edinb) 2013; 112:382-90. [PMID: 24220088 DOI: 10.1038/hdy.2013.116] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 08/20/2013] [Accepted: 09/19/2013] [Indexed: 11/08/2022] Open
Abstract
Begonia is one of the ten largest plant genera, with over 1500 species. This high species richness may in part be explained by weak species cohesion, which has allowed speciation by divergence in allopatry. In this study, we investigate species cohesion in the widespread Central American Begonia heracleifolia and Begonia nelumbiifolia, by genotyping populations at microsatellite loci. We then test for post-zygotic reproductive barriers using experimental crosses, and assess whether sterility barriers are related to intraspecific changes in genome size, indicating major genome restructuring between isolated populations. Strong population substructure was found for B. heracleifolia (FST=0.364, F'ST=0.506) and B. nelumbiifolia (FST=0.277, F'ST=0.439), and Bayesian admixture analysis supports the division of most populations into discrete genetic clusters. Moderate levels of inferred selfing (B. heracleifolia s=0.40, B. nelumbiifolia s=0.62) and dispersal limitation are likely to have contributed to significant genetic differentiation (B. heracleifolia Jost's D=0.274; B. nelumbiifolia D=0.294). Interpopulation crosses involving a divergent B. heracleifolia population with a genome size ∼10% larger than the species mean had a ∼20% reduction in pollen viability compared with other outcrosses, supporting reproductive isolation being polymorphic within the species. The population genetic data suggest that Begonia populations are only weakly connected by gene flow, allowing reproductive barriers to accumulate between the most isolated populations. This supports allopatric divergence in situ being the precursor of speciation in Begonia, and may also be a common speciation mechanism in other tropical herbaceous plant groups.
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Chumacero de Schawe C, Durka W, Tscharntke T, Hensen I, Kessler M. Gene flow and genetic diversity in cultivated and wild cacao (Theobroma cacao) in Bolivia. AMERICAN JOURNAL OF BOTANY 2013; 100:2271-2279. [PMID: 24158148 DOI: 10.3732/ajb.1300025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY The role of pollen flow within and between cultivated and wild tropical crop species is little known. To study the pollen flow of cacao, we estimated the degree of self-pollination and pollen dispersal distances as well as gene flow between wild and cultivated cacao (Theobroma cacao L.). METHODS We studied pollen flow and genetic diversity of cultivated and wild cacao populations by genotyping 143 wild and 86 cultivated mature plants and 374 seedlings raised from 19 wild and 25 cultivated trees at nine microsatellite loci. KEY RESULTS A principal component analysis distinguished wild and cultivated cacao trees, supporting the notion that Bolivia harbors truly wild cacao populations. Cultivated cacao had a higher level of genetic diversity than wild cacao, presumably reflecting the varied origin of cultivated plants. Both cacao types had high outcrossing rates, but the paternity analysis revealed 7-14% self-pollination in wild and cultivated cacao. Despite the tiny size of the pollinators, pollen was transported distances up to 3 km; wild cacao showed longer distances (mean = 922 m) than cultivated cacao (826 m). Our data revealed that 16-20% of pollination events occurred between cultivated and wild populations. CONCLUSIONS We found evidence of self-pollination in both wild and cultivated cacao. Pollination distances are larger than those typically reported in tropical understory tree species. The relatively high pollen exchange from cultivated to wild cacao compromises genetic identity of wild populations, calling for the protection of extensive natural forest tracts to protect wild cacao in Bolivia.
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Nakanishi A, Yoshimaru H, Tomaru N, Miura M, Manabe T, Yamamoto SI. Patterns of pollen flow in a dense population of the insect-pollinated canopy tree species Castanopsis sieboldii. J Hered 2012; 103:547-56. [PMID: 22573791 DOI: 10.1093/jhered/ess026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insect pollinations of tree species with high-density populations have rarely been studied. Since the density of adults can affect effective pollen dispersal, short-distance pollination, even by insects, may frequently occur in high-density populations. To test this prediction, we investigated pollination patterns in a high-density population of the insect-pollinated canopy tree species Castanopsis sieboldii by paternity analysis using genotypes at 8 microsatellite loci of 145 adult trees and 439 seeds from 11 seed parents in a 4-ha plot. We then explored their genetic effects on the population by calculating other population genetics parameters. Although C. sieboldii has high potential for long-distance dispersal of pollen (as indicated by a fat-tailed dispersal kernel), the cumulative pollination at the local scale was spatially limited and strongly dependent on the distance between parents due to the high density of adults. Genetic diversity estimates for pollen pools accepted by each seed parent converged on a maximum as the effective number of pollen parents increased. The genetic diversity of pollen pool bulked over all the seed parents from inside the plot did not differ from that of the total pollen pools. Therefore, although pollen flow from distant pollen parents may help to maintain the genetic diversity of offspring, pollen parents neighboring seed parents may be the main contributors to the genetic diversity of the offspring at the seed stage.
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Breed MF, Ottewell KM, Gardner MG, Lowe AJ. Clarifying climate change adaptation responses for scattered trees in modified landscapes. J Appl Ecol 2011. [DOI: 10.1111/j.1365-2664.2011.01969.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Mating system and pollen flow between remnant populations of the endangered tropical tree, Guaiacum sanctum (Zygophyllaceae). CONSERV GENET 2010. [DOI: 10.1007/s10592-010-0130-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Native bees mediate long-distance pollen dispersal in a shade coffee landscape mosaic. Proc Natl Acad Sci U S A 2010; 107:13760-4. [PMID: 20660738 DOI: 10.1073/pnas.1002490107] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coffee farms are often embedded within a mosaic of agriculture and forest fragments in the world's most biologically diverse tropical regions. Although shade coffee farms can potentially support native pollinator communities, the degree to which these pollinators facilitate gene flow for native trees is unknown. We examined the role of native bees as vectors of gene flow for a reproductively specialized native tree, Miconia affinis, in a shade coffee and remnant forest landscape mosaic. We demonstrate extensive cross-habitat gene flow by native bees, with pollination events spanning more than 1,800 m. Pollen was carried twice as far within shade coffee habitat as in nearby forest, and trees growing within shade coffee farms received pollen from a far greater number of sires than trees within remnant forest. The study shows that shade coffee habitats support specialized native pollinators that enhance the fecundity and genetic diversity of remnant native trees.
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Zhang JJ, Ye QG, Yao XH, Huang HW. Spontaneous interspecific hybridization and patterns of pollen dispersal in ex situ populations of a tree species (Sinojackia xylocarpa) that is extinct in the wild. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2010; 24:246-255. [PMID: 19906065 DOI: 10.1111/j.1523-1739.2009.01357.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
For endangered plants interspecific hybridization occurring in ex situ collections may lead to failure of reintroduction actions. We used Sinojackia xylocarpa, a well documented Chinese endemic species that is extinct in the wild, as a model case to address this concern. We used paternity analyses to assess the spontaneous hybridization and patterns of pollen flow between S. xylocarpa and its congener species, S. rehderiana, in conserved populations in Wuhan Botanic Garden. Interspecific hybridization events were detected in seven out of eight maternal trees of S. xylocarpa, and an average of 32.7% seeds collected from maternal trees of S. xylocarpa were hybrids. The paternity of 93 out of 249 seedlings from S. xylocarpa assigned to S. rehderiana provided convincing evidence that spontaneous interspecific hybridization occurred extensively in the living garden collection we studied. Different patterns of pollen dispersal (predominantly short-distance vs. long-distance pollination) were observed between intra- and interspecific hybridization events in the garden. Pollen dispersal within the ex situ populations was not restricted by distance, as evidenced by a lack of significant correlations between the average effective pollen dispersal distance (delta) and the geographic distances (d1 and d2) between maternal and paternal trees. The interspecific pollen-dispersal distance ranged from 10 to 620.1 m (mean 294.4 m). Such extensive hybridization in ex situ collections could jeopardize the genetic integrity of endangered species and irrevocably contaminate the gene pool if such hybrids are used for reintroduction and restoration. We recommend strongly that measures be taken to minimize the genetic risks of this kind of hybridization, including establishing buffer zones in ex situ collections, manipulating flowering phenology, testing seed lots before use in reintroduction programs, and controlling pollination for seed purity.
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Affiliation(s)
- Jin-Ju Zhang
- Wuhan Botanical Garden/Wuhan Institute of Botany, Chinese Academy of Sciences, Wuhan 430074, Hubei, China
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21
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Chapman MA, Hvala J, Strever J, Matvienko M, Kozik A, Michelmore RW, Tang S, Knapp SJ, Burke JM. Development, polymorphism, and cross-taxon utility of EST-SSR markers from safflower (Carthamus tinctorius L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2009; 120:85-91. [PMID: 19820913 DOI: 10.1007/s00122-009-1161-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 09/11/2009] [Indexed: 05/13/2023]
Abstract
Due to their highly polymorphic and codominant nature, simple-sequence repeat (SSR) markers are a common choice for assaying genetic diversity and genetic mapping. In this paper, we describe the generation of an expressed-sequence tag (EST) collection for the oilseed crop safflower and the subsequent development of EST-SSR markers for the genetic analysis of safflower and related species. We assembled 40,874 reads into 19,395 unigenes, of which 4,416 (22.8%) contained at least one SSR. Primer pairs were developed and tested for 384 of these loci, resulting in a collection of 104 polymorphic markers that amplify reliably across 27 accessions (3 species) of the genus Carthamus. These markers exhibited a high level of polymorphism, with an average of 6.0 +/- 0.4 alleles per locus and an average gene diversity of 0.54 +/- 0.03 across Carthamus species. In terms of cross-taxon transferability, 50% of these primer pairs produced an amplicon in at least one other species in the Asteraceae, and 28% produced an amplicon in at least one species outside the safflower subfamily (i.e., lettuce, sunflower, and/or Gerbera). These markers represent a valuable resource for the genetic analysis of safflower and related species, and also have the potential to facilitate comparative map-based analyses across a broader array of taxa within the Asteraceae.
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Affiliation(s)
- Mark A Chapman
- Department of Plant Biology, University of Georgia, Miller Plant Sciences Building, Athens, GA 30602, USA.
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22
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Wind-borne insects mediate directional pollen transfer between desert fig trees 160 kilometers apart. Proc Natl Acad Sci U S A 2009; 106:20342-7. [PMID: 19910534 DOI: 10.1073/pnas.0902213106] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The question of how far pollen can move between plants has implications for topics as diverse as habitat fragmentation, conservation management, and the containment of genetically modified crops. The monoecious African fig tree Ficus sycomorus L. relies on the small, short-lived, night-flying, host-specific fig wasp Ceratosolen arabicus Mayr for pollination. We used microsatellite markers to characterize a geographically isolated riparian population of F. sycomorus growing along the Ugab River in the Namib Desert, Namibia, together with paternity analysis of seedlings from known mothers, to map pollen movement within this population. In this way we tracked insect movements between individually recognizable trees by means of their pollen cargo and documented the movement of C. arabicus between known trees separated by more than 160 km, with a mean distance for confirmed successful pollination events of 88.6 km. The predominant observed movement of pollinators was in a westerly direction, toward the sea, reflecting seasonal nighttime wind direction and the wind-borne dispersal of fig wasps. Our results suggest the existence of an extensive panmictic population of trees that are well suited to overcome the effects of geographical isolation.
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Iwaizumi MG, Takahashi M, Watanabe A, Ubukata M. Simultaneous Evaluation of Paternal and Maternal Immigrant Gene Flow and the Implications for the Overall Genetic Composition of Pinus densiflora Dispersed Seeds. J Hered 2009; 101:144-53. [DOI: 10.1093/jhered/esp089] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Kamm U, Rotach P, Gugerli F, Siroky M, Edwards P, Holderegger R. Frequent long-distance gene flow in a rare temperate forest tree (Sorbus domestica) at the landscape scale. Heredity (Edinb) 2009; 103:476-82. [PMID: 19654608 DOI: 10.1038/hdy.2009.70] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Precise empirical data on current gene flow by pollen, both with respect to distance and abundance, is crucial to understand whether habitat fragments are functionally connected. Based on a large-scale inventory ( approximately 100 km(2)) in which all individuals of a naturally scattered forest tree (Sorbus domestica) were mapped, we inferred current gene flow by pollen using genetic paternity analysis. We detected an extensive network of effective pollen transfer. Although short pollen flow distances were most abundant, 10% of the assigned pollen donors were more than 2 km away from their female mating partners, and 1.8% were even at a distance of 12-16 km. This latter pollen flow shows that current long-distance gene flow over a fragmented landscape clearly occurs. Pollen dispersal was well described by a fat-tailed inverse curve. Using parentage analysis of established trees, maternally inherited chloroplast markers and diameter at breast height measurements as an indicator of individual tree age, we were able to infer regular seed dispersal distances over several hundred metres up to more than 10 km. We conclude that in temperate, insect-pollinated and animal-dispersed tree species such as S. domestica, fragmented subpopulations are functionally connected by gene flow through both pollen and seed.
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Affiliation(s)
- U Kamm
- WSL, Swiss Federal Research Institute, Birmensdorf, Switzerland.
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25
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Ng CH, Lee SL, Ng KKS, Muhammad N, Ratnam W. Mating system and seed variation of Acacia hybrid (A. mangium x A. auriculiformis). J Genet 2009; 88:25-31. [PMID: 19417541 DOI: 10.1007/s12041-009-0004-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The mating system and seed variation of Acacia hybrid (A. mangium x A. auriculiformis) were studied using allozymes and random amplified polymorphic DNA (RAPD) markers, respectively. Multi-locus outcrossing rate estimations indicated that the hybrid was predominantly outcrossed (mean+/- s.e. t(m) = 0.86+/-0.01). Seed variation was investigated using 35 polymorphic RAPD fragments. An analysis of molecular variance (AMOVA) revealed the highest genetic variation among seeds within a pod (66%-70%), followed by among pods within inflorescence (29%-37%), and the least variation among inflorescences within tree (1%). In addition, two to four RAPD profiles could be detected among seeds within pod. Therefore, the results suggest that a maximum of four seeds per pod could be sampled for the establishment of a mapping population for further studies.
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Affiliation(s)
- Chin-Hong Ng
- Genetic Unit, Forest Biotechnology and Pharmaceutical Programme, Forest Research Institute Malaysia,52109 Kepong, Malaysia.
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26
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Geng Q, Lian C, Goto S, Tao J, Kimura M, Islam MS, Hogetsu T. Mating system, pollen and propagule dispersal, and spatial genetic structure in a high-density population of the mangrove tree Kandelia candel. Mol Ecol 2009; 17:4724-39. [PMID: 19140988 DOI: 10.1111/j.1365-294x.2008.03948.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mangrove tree species form ecologically and economically important forests along the tropical and subtropical coastlines of the world. Although low intrapopulation genetic diversity and high interpopulation genetic differentiation have been detected in most mangrove tree species, no direct investigation of pollen and propagule dispersal through paternity and/or parentage analysis and spatial genetic structure within populations has been conducted. We surveyed the mating system, pollen and propagule dispersal, and spatial genetic structure in a natural population of Kandelia candel, one of the typical viviparous mangrove tree species, using nuclear and chloroplast microsatellite markers. High diversity and outcrossing rates were observed. Paternity and parentage analysis and modelling estimations revealed the presence of an extremely short-distance component of pollen and propagule dispersal (pollen: 15.2+/-14.9 m (SD) by paternity analysis and 34.4 m by modelling; propagule: 9.4+/-13.8 m (SD) by parentage analysis, and 18.6 m by modelling). Genetic structure was significant at short distances, and a clumped distribution of chloroplast microsatellite genotypes was seen in K. candel adults. We conclude that the K. candel population was initiated by limited propagule founders from outside by long-distance dispersal followed by limited propagule dispersal from the founders, resulting in a half-sib family structure.
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Affiliation(s)
- Qifang Geng
- Asian Natural Environmental Science Center, University of Tokyo, Midori-cho 1-1-8, Nishitokyo, Tokyo 188-0002, Japan
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27
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Effects of seed- and pollen-mediated gene dispersal on genetic structure among Quercus salicina saplings. Heredity (Edinb) 2008; 102:182-9. [DOI: 10.1038/hdy.2008.101] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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28
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Kramer AT, Ison JL, Ashley MV, Howe HF. The paradox of forest fragmentation genetics. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2008; 22:878-85. [PMID: 18544089 DOI: 10.1111/j.1523-1739.2008.00944.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Theory predicts widespread loss of genetic diversity from drift and inbreeding in trees subjected to habitat fragmentation, yet empirical support of this theory is scarce. We argue that population genetics theory may be misapplied in light of ecological realities that, when recognized, require scrutiny of underlying evolutionary assumptions. One ecological reality is that fragment boundaries often do not represent boundaries for mating populations of trees that benefit from long-distance pollination, sometimes abetted by long-distance seed dispersal. Where fragments do not delineate populations, genetic theory of small populations does not apply. Even in spatially isolated populations, where genetic theory may eventually apply, evolutionary arguments assume that samples from fragmented populations represent trees that have had sufficient time to experience drift, inbreeding, and ultimately inbreeding depression, an unwarranted assumption where stands in fragments are living relicts of largely unrelated predisturbance populations. Genetic degradation may not be as important as ecological degradation for many decades following habitat fragmentation.
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Affiliation(s)
- Andrea T Kramer
- Department of Biological Sciences (M/C 066), University of Illinois at Chicago, 845 W. Taylor Street, Chicago, IL 60607, USA
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29
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García C, Jordano P, Godoy JA. Contemporary pollen and seed dispersal in a Prunus mahaleb population: patterns in distance and direction. Mol Ecol 2007; 16:1947-55. [PMID: 17444903 DOI: 10.1111/j.1365-294x.2006.03126.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Pollination and seed dispersal determine the spatial pattern of gene flow in plant populations and, for those species relying on pollinators and frugivores as dispersal vectors, animal activity plays a key role in determining this spatial pattern. For these plant species, reported dispersal patterns are dominated by short-distance movements with a significant amount of immigration. However, the contribution of seed and pollen to the overall contemporary gene immigration is still poorly documented for most plant populations. In this study we investigated pollination and seed dispersal at two spatial scales in a local population of Prunus mahaleb (L.), a species pollinated by insects and dispersed by frugivorous vertebrates. First, we dissected the relative contribution of pollen and seed dispersal to gene immigration from other parts of the metapopulation. We found high levels of gene immigration (18.50%), due to frequent long distance seed dispersal events. Second, we assessed the distance and directionality for pollen and seed dispersal events within the local population. Pollen and seed movement patterns were non-random, with skewed distance distributions: pollen tended moved up to 548 m along an axis approaching the N-S direction, and seeds were dispersed up to 990 m, frequently along the SW and SE axes. Animal-mediated dispersal contributed significantly towards gene immigration into the local population and had a markedly nonrandom pattern within the local population. Our data suggest that animals can impose distinct spatial signatures in contemporary gene flow, with the potential to induce significant genetic structure at a local level.
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Affiliation(s)
- C García
- Integrative Ecology Group, Estación Biológica de Doñana, CSIC, Pabellón del Perú, Avda. María Luisa, s/n, E-41013 Sevilla, Spain.
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Luna R, Epperson BK, Oyama K. High levels of genetic variability and inbreeding in two Neotropical dioecious palms with contrasting life histories. Heredity (Edinb) 2007; 99:466-76. [PMID: 17637694 DOI: 10.1038/sj.hdy.6801027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We characterized the population genetics of two Neotropical dioecious palm species of Chamaedorea with contrasting life strategies from the region that is both the northernmost extent and most species rich of the genus. Chamaedorea tepejilote is a common, wind-pollinated arboreal understory palm. Although most adult plants reproduce each year, only a few individuals produce the majority of flowers and seeds. Chamaedorea elatior, conversely, is an uncommon climbing subcanopy palm with entomophilous flowers (insect-pollinated characteristics). Most of the mature palms do not reproduce in consecutive years and fruiting is episodic. Isozymes with a total of 107 alleles for 27 loci of 17 enzymes from six populations were assessed. For both species, co-occurrence of high levels of genetic variation and homozygosity was observed (C. tepejilote: He: 0.385-0.442, f: 0.431-0.486; C. elatior: He: 0.278-0.342, f: 0.466-0.535). Genetic differentiation of C. elatior was much lower (theta=0.0315) than that for C. tepejilote (theta=0.152). The contrast in differentiation may be influenced by differences in the spatial scale of the genetic neighborhoods of the two species. The simultaneous maintenance of inbreeding and of a large number of alleles within the populations is attributable to the low and variable number of mating pairs. Demographic studies indicate that this pattern could be explained by low reproductive frequency among individuals and over years in C. elatior and by reproductive dominance in C. tepejilote.
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Affiliation(s)
- R Luna
- Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
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31
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Cloutier D, Hardy OJ, Caron H, Ciampi AY, Degen B, Kanashiro M, Schoen DJ. Low Inbreeding and High Pollen Dispersal Distances in Populations of Two Amazonian Forest Tree Species. Biotropica 2007. [DOI: 10.1111/j.1744-7429.2007.00266.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Byrne M, Elliott CP, Yates CJ, Coates DJ. Maintenance of high pollen dispersal in Eucalyptus wandoo, a dominant tree of the fragmented agricultural region in Western Australia. CONSERV GENET 2007. [DOI: 10.1007/s10592-007-9311-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wilson IJ, Dawson KJ. A Markov chain Monte Carlo strategy for sampling from the joint posterior distribution of pedigrees and population parameters under a Fisher-Wright model with partial selfing. Theor Popul Biol 2007; 72:436-58. [PMID: 17448511 DOI: 10.1016/j.tpb.2007.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 02/28/2007] [Accepted: 03/05/2007] [Indexed: 11/17/2022]
Abstract
A simple population genetic model is presented for a hermaphrodite annual species, allowing both selfing and outcrossing. Those male gametes (pollen) responsible for outcrossing are assumed to disperse much further than seeds. Under this model, the pedigree of a sample from a single locality is loop-free. A novel Markov chain Monte Carlo strategy is presented for sampling from the joint posterior distribution of the pedigree of such a sample and the parameters of the population genetic model (including the selfing rate) given the genotypes of the sampled individuals at unlinked marker loci. The computational costs of this Markov chain Monte Carlo strategy scale well with the number of individuals in the sample, and the number of marker loci, but increase exponentially with the age (time since colonisation from the source population) of the local population. Consequently, this strategy is particularly suited to situations where the sample has been collected from a population which is the result of a recent colonisation process.
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Affiliation(s)
- Ian J Wilson
- Institute of Human Genetics, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
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Craft KJ, Owens JD, Ashley MV. Application of plant DNA markers in forensic botany: Genetic comparison of Quercus evidence leaves to crime scene trees using microsatellites. Forensic Sci Int 2007; 165:64-70. [PMID: 16632287 DOI: 10.1016/j.forsciint.2006.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 03/03/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
As highly polymorphic DNA markers become increasingly available for a wide range of plant and animal species, there will be increasing opportunities for applications to forensic investigations. To date, however, relatively few studies have reported using DNA profiles of non-human species to place suspects at or near crime scenes. Here we describe an investigation of a double homicide of a female and her near-term fetus. Leaf material taken from a suspect's vehicle was identified to be that of sand live oak, Quercus geminata, the same tree species that occurred near a shallow grave where the victims were found. Quercus-specific DNA microsatellites were used to genotype both dried and fresh material from trees located near the burial site and from the material taken from the suspect's car. Samples from the local population of Q. geminata were also collected and genotyped in order to demonstrate that genetic variation at four microsatellite loci was sufficient to assign leaves to an individual tree with high statistical certainty. The cumulative average probability of identity for these four loci was 2.06x10(-6). DNA was successfully obtained from the dried leaf material although PCR amplification was more difficult than amplification of DNA from fresh leaves. The DNA profiles of the dried leaves from the suspect's car did not match those of the trees near the crime scene. Although this investigation did not provide evidence that could be used against the suspect, it does demonstrate the potential for plant microsatellite markers providing physical evidence that links plant materials to live plants at or near crime scenes.
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Affiliation(s)
- Kathleen J Craft
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
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Setsuko S, Ishida K, Ueno S, Tsumura Y, Tomaru N. Population differentiation and gene flow within a metapopulation of a threatened tree, Magnolia stellata (Magnoliaceae). AMERICAN JOURNAL OF BOTANY 2007; 94:128-136. [PMID: 21642215 DOI: 10.3732/ajb.94.1.128] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We examined genetic differentiation among eight local populations of a metapopulation of Magnolia stellata using 10 nuclear and three chloroplast microsatellite (nSSR and cpSSR) markers and evaluated the influence of historical gene flow on population differentiation. The coefficient of genetic differentiation among populations for nSSR (F(ST) = 0.053) was less than half that for cpSSR (0.137). An isolation-by-distance pattern was detected for nSSRs, but not cpSSRs. These results suggest that pollen flow, as well as seed dispersal, has significantly reduced genetic differentiation among populations. We also examined patterns of contemporary pollen flow by paternity analysis of seeds from nine seed parents in one of the populations using the nSSR markers and found it to be greatly restricted by the distance between parents. Although most pollen flow occurred within the population, pollen flow from outside the population accounted for 2.5% of the total. When historical and contemporary pollen flows among populations were compared, the levels of pollen flow seem to have declined recently. We conclude that to conserve M. stellata, it is important to preserve the whole population by maintaining its metapopulation structure and the gene flow among its populations.
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Affiliation(s)
- Suzuki Setsuko
- Laboratory of Forest Ecology and Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Evidences of introgression from cultivated rice to Oryza rufipogon (Poaceae) populations based on SSR fingerprinting: implications for wild rice differentiation and conservation. Evol Ecol 2006. [DOI: 10.1007/s10682-006-9113-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zartman CE, McDaniel SF, Shaw AJ. Experimental habitat fragmentation increases linkage disequilibrium but does not affect genetic diversity or population structure in the Amazonian liverwort Radula flaccida. Mol Ecol 2006; 15:2305-15. [PMID: 16842407 DOI: 10.1111/j.1365-294x.2006.02929.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Habitat fragmentation increases the migration distances among remnant populations, and is predicted to play a significant role in altering both demographic and genetic processes. Nevertheless, few studies have evaluated the genetic consequences of habitat fragmentation in light of information about population dynamics in the same set of organisms. In a 10,000-km(2) experimentally fragmented landscape of rainforest reserves in central Amazonia, we examine patterns of genetic variation (amplified fragment length polymorphisms, AFLPs) in the epiphyllous (e.g. leaf-inhabiting) liverwort Radula flaccida Gott. Previous demographic work indicates that colonization rates in this species are significantly reduced in small forest reserves. We scored 113 polymorphic loci in 86 individuals representing five fragmented and five experimentally unmanipulated populations. Most of the variation (82%) in all populations was harboured at the smallest (400 m(2)) sampling unit. The mean ((+/-) SD) within-population genetic diversity (Nei's), of forest remnants (0.412 +/- 0.2) was indistinguishable from continuous (0.413 +/- 0.2) forests. Similarly, F(ST) was identical among small (1- and 10-ha) and large (> or = 100-ha) reserves (0.19 and 0.18, respectively), but linkage disequilibrium between pairs of loci was significantly elevated in fragmented populations relative to those in continuous forests. These results illustrate that inferences regarding the long-term viability of fragmented populations based on neutral marker data alone must be viewed with caution, and underscore the importance of jointly evaluating information on both genetic structure and demography. Second, multilocus analyses may be more sensitive to the effects of fragmentation in the short term, although the effects of increasing linkage disequilibrium on population viability remain uncertain.
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Affiliation(s)
- Charles E Zartman
- Department of Biology, Duke University, Box 90338, Durham, North Carolina 27707, USA.
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Nakanishi A, Tomaru N, Yoshimaru H, Manabe T, Yamamoto S. Interannual genetic heterogeneity of pollen pools accepted by Quercus salicina individuals. Mol Ecol 2006; 14:4469-78. [PMID: 16313607 DOI: 10.1111/j.1365-294x.2005.02736.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since flowering often varies among years in wind-pollinated woody species, the genetic composition of pollen pools accepted by seed parents can differ between years. The interannual heterogeneity of pollen flow may be important for maintaining genetic diversity within populations because it can increase genetic variation within populations and the effective sizes of the populations. In this study we examined heterogeneity, using paternity analysis and analysis of molecular variance, in the genetic composition of pollen pools among different reproductive years for six Quercus salicina seed parents in an 11.56-ha plot in a temperate old-growth evergreen broadleaved forest. The genotypes at seven microsatellite loci were determined for 111 adult trees and 777 offspring of the six seed parents in 2-5 reproductive years. Genetic differentiation of pollen pools among different reproductive years for each seed parent was significant over all seed parents and for each of four seed parents that were analysed for more than 2 years, but not for either of the other two seed parents (analysed for 2 years). For both the pollen pools originating from inside the plot and those originating from outside it, genetic differentiation among different reproductive years for each seed parent was significant over all seed parents. However, among-year genetic differentiation in the pollen pools originating from within the plot was detected for all four of the seed parents that were analysed for more than 2 years, but for only one of the four in the pools originating from outside the plot. Genetic diversity (estimated as allelic richness and gene diversity) was higher for pollen pools over all reproductive years than for pollen pools in single years. These results indicate that the year-to-year genetic variation of pollen pools increases genetic diversity in offspring and is strongly affected by the variation in pollen parents within the plot because of their high pollination contributions. The high year-to-year variation in pollen parents within the plot and overall supports the hypothesis that the offspring produced across years represent a larger genetic neighbourhood.
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Affiliation(s)
- A Nakanishi
- Laboratory of Forest Ecology and Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
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Hardy OJ, Maggia L, Bandou E, Breyne P, Caron H, Chevallier MH, Doligez A, Dutech C, Kremer A, Latouche-Hallé C, Troispoux V, Veron V, Degen B. Fine-scale genetic structure and gene dispersal inferences in 10 neotropical tree species. Mol Ecol 2006; 15:559-71. [PMID: 16448421 DOI: 10.1111/j.1365-294x.2005.02785.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The extent of gene dispersal is a fundamental factor of the population and evolutionary dynamics of tropical tree species, but directly monitoring seed and pollen movement is a difficult task. However, indirect estimates of historical gene dispersal can be obtained from the fine-scale spatial genetic structure of populations at drift-dispersal equilibrium. Using an approach that is based on the slope of the regression of pairwise kinship coefficients on spatial distance and estimates of the effective population density, we compare indirect gene dispersal estimates of sympatric populations of 10 tropical tree species. We re-analysed 26 data sets consisting of mapped allozyme, SSR (simple sequence repeat), RAPD (random amplified polymorphic DNA) or AFLP (amplified fragment length polymorphism) genotypes from two rainforest sites in French Guiana. Gene dispersal estimates were obtained for at least one marker in each species, although the estimation procedure failed under insufficient marker polymorphism, limited sample size, or inappropriate sampling area. Estimates generally suffered low precision and were affected by assumptions regarding the effective population density. Averaging estimates over data sets, the extent of gene dispersal ranged from 150 m to 1200 m according to species. Smaller gene dispersal estimates were obtained in species with heavy diaspores, which are presumably not well dispersed, and in populations with high local adult density. We suggest that limited seed dispersal could indirectly limit effective pollen dispersal by creating higher local tree densities, thereby increasing the positive correlation between pollen and seed dispersal distances. We discuss the potential and limitations of our indirect estimation procedure and suggest guidelines for future studies.
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Affiliation(s)
- Olivier J Hardy
- Université Libre de Bruxelles, Service d'Eco-Ethologie Evolutive, CP 160/12, 50 Av. F. Roosevelt, B-1050 Brussels, Belgium.
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40
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Lowe AJ, Boshier D, Ward M, Bacles CFE, Navarro C. Genetic resource impacts of habitat loss and degradation; reconciling empirical evidence and predicted theory for neotropical trees. Heredity (Edinb) 2006; 95:255-73. [PMID: 16094300 DOI: 10.1038/sj.hdy.6800725] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The theoretical impacts of anthropogenic habitat degradation on genetic resources have been well articulated. Here we use a simulation approach to assess the magnitude of expected genetic change, and review 31 studies of 23 neotropical tree species to assess whether empirical case studies conform to theory. Major differences in the sensitivity of measures to detect the genetic health of degraded populations were obvious. Most studies employing genetic diversity (nine out of 13) found no significant consequences, yet most that assessed progeny inbreeding (six out of eight), reproductive output (seven out of 10) and fitness (all six) highlighted significant impacts. These observations are in line with theory, where inbreeding is observed immediately following impact, but genetic diversity is lost slowly over subsequent generations, which for trees may take decades. Studies also highlight the ecological, not just genetic, consequences of habitat degradation that can cause reduced seed set and progeny fitness. Unexpectedly, two studies examining pollen flow using paternity analysis highlight an extensive network of gene flow at smaller spatial scales (less than 10 km). Gene flow can thus mitigate against loss of genetic diversity and assist in long-term population viability, even in degraded landscapes. Unfortunately, the surveyed studies were too few and heterogeneous to examine concepts of population size thresholds and genetic resilience in relation to life history. Future suggested research priorities include undertaking integrated studies on a range of species in the same landscapes; better documentation of the extent and duration of impact; and most importantly, combining neutral marker, pollination dynamics, ecological consequences, and progeny fitness assessment within single studies.
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Affiliation(s)
- A J Lowe
- School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia.
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41
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Ishida K. Maintenance of Inbreeding Depression in a Highly Self-Fertilizing Tree, Magnolia obovata Thunb. Evol Ecol 2006. [DOI: 10.1007/s10682-005-5748-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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42
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Abstract
The ecological significance of spacing among plants in contributing to the maintenance of species richness, particularly in tropical forests, has received considerable attention that has largely focussed on distance- and density-dependent seed and seedling mortality. More recently it has become apparent that plant spacing is also relevant to pollination, which often constrains seed production. While seed and seedling survival is reduced at high conspecific densities, pollination success, by contrast, is positively correlated to local conspecific density. Distance-dependent mechanisms acting on pollination and seed production have now been described for a variety of plants, with relatively isolated plants or fragmented populations generally suffering reduced fecundity due to pollen limitation. Yet there is considerable variability in the vulnerability of plant species to pollination failure, which may be a function of breeding system, life history, the pollination vector, the degree of specialisation among plants and their pollinators, and other indirect effects of habitat change acting on plants or pollinators. As reduced tree densities and population fragmentation are common outcomes of anthropogenically altered landscapes, understanding how pollination processes are affected in such degraded landscapes can inform effective conservation and management of remaining natural areas.
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Affiliation(s)
- Jaboury Ghazoul
- Department of Environmental Sciences, Imperial College London, Silwood Park, Ascot, Berks SL5 7PT, UK.
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García C, Arroyo JM, Godoy JA, Jordano P. Mating patterns, pollen dispersal, and the ecological maternal neighbourhood in a Prunus mahaleb L. population. Mol Ecol 2005; 14:1821-30. [PMID: 15836653 DOI: 10.1111/j.1365-294x.2005.02542.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gender polymorphism, plant-animal interactions, and environmental heterogeneity are the three important sources of variation in mating system and pollen dispersal patterns. We used progeny arrays and paternity analysis to assess the effects of gender type and density level on variation in mating patterns within a highly isolated population of Prunus mahaleb, a gynodioecious species. All the adult trees in the population were sampled and located. The direct estimate of long-distance insect-mediated pollination events was low (< 10%). Gender expression deeply influenced the mating system, decreasing the outcrossing rates (t(m)) and the pollen pool diversity in hermaphrodite trees. Long intermate distances (> 250 m) were significantly more frequent among female mother trees. Variation in local tree density also affected pollen pool diversity and intermate distance, with a higher effective number of fathers (k(e)) and longer intermate distances for female trees in low-density patches. A canonical correlation analysis showed significant correlations between mating variables and the maternal ecological neighbourhood. Only the first canonical variable was significant and explained 78% of variation. Outcrossing rates tended to decrease, and the relatedness among the fathers tended to increase, when mother trees grew in dense patches with high cover of other woody species and taller vegetation away from the pine forest edge. We highlight the relevance of considering maternal ecological neighbourhood effects on mating system and gene flow studies as maternal trees act simultaneously as receptors of pollen and as sources of the seeds to be dispersed.
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Affiliation(s)
- C García
- Integrative Ecology Group, Estación Biológica de Doñana, CSIC, Pabellón del Perú, Avda. María Luisa, s/n, E-41013 Sevilla, Spain.
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44
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Abstract
Understanding mating patterns and gene movement in plant populations occupying highly disturbed landscapes is essential for insights into their long-term survival. We used allozyme genetic markers to examine mating patterns and to directly measure pollen flow in the Central American epiphytic orchid, Laelia rubescens. Study populations were located in disturbed, seasonally dry tropical forest in Costa Rica. Every flowering individual within 15 populations and 12-18 seedlings from each maternal individual were genotyped over two reproductive seasons. Strict correlated mating by orchids produces full-sib progeny arrays from which the multilocus diploid genotype of the pollen parent can be inferred. These paternity analyses produced detailed quantitative estimates of pollen movement within and among populations of this species. Although our data illustrate that mating patterns vary spatially and temporally among trees, among pastures, and between years, overall patterns were surprisingly consistent. Thirty-four per cent of the capsules produced in both years resulted from gene flow events. Where pollen parents were identified, pollen moved mean distances of 279 m and 519 m in 1999 and 2000 respectively and a maximum documented distance of 1034 m. A substantially larger floral display in 2000 corresponded to a marked increase in pollen dispersal distances. Smaller populations, which more closely resembled those in undisturbed forest, had higher rates of gene flow than the large populations that characterize disturbed sites. We predict the occurrence of greater gene flow between low-density populations occupying undisturbed habitats.
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Affiliation(s)
- D W Trapnell
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA.
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45
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Kenta T, Isagi Y, Nakagawa M, Yamashita M, Nakashizuka T. Variation in pollen dispersal between years with different pollination conditions in a tropical emergent tree. Mol Ecol 2005; 13:3575-84. [PMID: 15488013 DOI: 10.1111/j.1365-294x.2004.02345.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We examined differences in pollen dispersal efficiency between 2 years in terms of both spatial dispersal range and genetic relatedness of pollen in a tropical emergent tree, Dipterocarpus tempehes. The species was pollinated by the giant honeybee (Apis dorsata) in a year of intensive community-level mass-flowering or general flowering (1996), but by several species of moths in a year of less-intensive general flowering (1998). We carried out paternity analysis based on six DNA microsatellite markers on a total of 277 mature trees forming four spatially distinct subpopulations in a 70 ha area, and 147 and 188 2-year-old seedlings originating from seeds produced in 1996 and 1998 (cohorts 96 and 98, respectively). Outcrossing rates (0.93 and 0.96 for cohorts 96 and 98, respectively) did not differ between years. Mean dispersal distances (222 and 192 m) were not significantly different between the 2 years but marginally more biased to long distance in 1996. The mean relatedness among cross-pollinated seedlings sharing the same mothers in cohort 96 was lower than that in cohort 98. This can be attributed to the two facts that the proportion of intersubpopulations pollen flow among cross-pollination events was marginally higher in cohort 96 (44%) than in cohort 98 (33%), and that mature trees within the same subpopulations are genetically more related to each other than those between different subpopulations. We conclude that D. tempehes maintained effective pollen dispersal in terms of outcrossing rate and pollen dispersal distance in spite of the large difference in foraging characteristics between two types of pollinators. In terms of pollen relatedness, however, a slight difference was suggested between years in the level of biparental inbreeding.
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Affiliation(s)
- T Kenta
- Center for Ecological Research, Kyoto University, Kamitanakami-Hirano, Ohtsu, 520-0113 Japan.
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46
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Sezen UU, Chazdon RL, Holsinger KE. Genetic Consequences of Tropical Second-Growth Forest Regeneration. Science 2005; 307:891. [PMID: 15705843 DOI: 10.1126/science.1105034] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Secondary forests are more extensive than old-growth forests in many tropical regions, yet the genetic composition of colonizing populations is poorly understood. We analyzed the parentage of a founder population of 130 individuals of the canopy palm Iriartea deltoidea in a 24-year-old second-growth forest in lowland Costa Rica. Among 66 trees in adjacent old-growth forest, only two individuals contributed 56% of the genes in founders. Second-growth trees had lower genetic diversity and larger patches of similar genotypes than old-growth trees. Recovery of genetic diversity of populations in tropical second-growth forests may take many generations and will require continued dispersal from genetically diverse source populations.
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Affiliation(s)
- Uzay U Sezen
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA.
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47
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Iddrisu MN, Ritland K. Genetic variation, population structure, and mating system in bigleaf maple (AcermacrophyllumPursh). ACTA ACUST UNITED AC 2004. [DOI: 10.1139/b04-136] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genetic diversity, population genetic structure, and mating system of bigleaf maple (Acer macrophyllum Pursh) was estimated with isozymes and compared with other North American angiosperms. On average, populations were polymorphic at 61% of the loci, with 1.71 alleles per locus. The mean expected heterozygosity (HE= 0.152) was similar to other North American angiosperms. The level of population differentiation was moderately low (FST= 0.054), indicating extensive gene flow among populations (Nm= 4.39), and there was no isolation by distance. Genetic distances averaged 0.011 and ranged from 0.001 to 0.042, but no relationship between geographic distances was apparent. Outcrossing rates in two populations were high (95%) but significantly less than one, with no biparental inbreeding evident. A relatively high level of correlated matings, consistent with two to five effective pollen donors per tree, was found, indicating that low density and limited pollinator dispersal are prevalent.Key words: isozymes, bigleaf maple, outcrossing rates, population genetics, gene flow, angiosperms.
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48
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Rong J, Xia H, Zhu Y, Wang Y, Lu BR. Asymmetric gene flow between traditional and hybrid rice varieties (Oryza sativa) indicated by nuclear simple sequence repeats and implications for germplasm conservation. THE NEW PHYTOLOGIST 2004; 163:439-445. [PMID: 33873619 DOI: 10.1111/j.1469-8137.2004.01100.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• Mixed-planting of traditional and hybrid rice (Oryza sativa) varieties is an ecological approach for rice disease control and yield increase, in addition to its effective role in in situ conservation of traditional rice varieties. To estimate gene flow between traditional and hybrid rice varieties, an experiment involving Huangkenuo and Shanyou-63 was conducted to allow free gene flow by mixed-planting of the two varieties in different cultivation patterns. • A simple sequence repeat (SSR) marker RM167 was used to detect natural hybrids between the two varieties by examining seeds collected randomly from both varieties in the experiment. • The result showed an extremely low number of hybrids between the two varieties with an average frequency of 0.04% in Huangkenuo and 0.18% in Shanyou-63. • It is concluded that no significant gene flow occurs naturally between Huangkenuo and Shanyou-63, and that crop diversity management is a proper means for in situ conservation of traditional rice varieties. It is also implied that the potential transgene flow from transgenic hybrid rice to traditional rice variety would be extremely low.
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Affiliation(s)
- Jun Rong
- The Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
| | - Hui Xia
- The Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
| | - Youyong Zhu
- Ministry of Education Key Laboratory of Agriculture Biodiversity for Plant Disease Management, Key Laboratory of Plant Pathology, Yunnan Agricultural University, Kunming 650201, China
| | - Yunyue Wang
- Ministry of Education Key Laboratory of Agriculture Biodiversity for Plant Disease Management, Key Laboratory of Plant Pathology, Yunnan Agricultural University, Kunming 650201, China
| | - Bao-Rong Lu
- The Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
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49
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Latouche-Hallé C, Ramboer A, Bandou E, Caron H, Kremer A. Long-distance pollen flow and tolerance to selfing in a neotropical tree species. Mol Ecol 2004; 13:1055-64. [PMID: 15078444 DOI: 10.1111/j.1365-294x.2004.02127.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Outcrossing rates, pollen dispersal and male mating success were assessed in Dicorynia guianensis Amshoff, a neotropical tree endemic to the Guiana shield. All adult trees within a continuous area of 40 ha (n = 157) were mapped, and were genotyped with six microsatellite loci. In addition, progenies were genotyped from 22 mature trees. At the population level, the species was mostly outcrossing (tm = 0.89) but there was marked variation among individuals. One tree exhibited mixed mating, confirming earlier results obtained with isozymes that D. guianensis can tolerate selfing. A Bayesian extension of the fractional paternity method was used for paternity analysis, and was compared with the neighbourhood method used widely for forest trees. Both methods indicated that pollen dispersal was only weakly related to distance between trees within the study area, and that the majority (62%) of pollen came from outside the study stand. Using maximum likelihood, male potential population size was estimated to be 1119, corresponding to a neighbourhood size of 560 hectares. Male mating success was, however, related to the diameter of the stem and to flowering intensity assessed visually. The mating behaviour of D. guianensis is a combination of long-distance pollen flow and occasional selfing. The species can still reproduce when it is extremely rare, either by selfing or by dispersing pollen at long distances. These results, together with the observation that male mating success was correlated with the size of the trees, could be implemented in management procedures aiming at regenerating the species.
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Affiliation(s)
- C Latouche-Hallé
- INRA UMR BIOGECO, Biodiverity, Genes & Ecosystems, 69, route d'Arcachon 33610-Cestas, France
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50
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Novick RR, Dick CW, Lemes MR, Navarro C, Caccone A, Bermingham E. Genetic structure of Mesoamerican populations of Big-leaf mahogany (Swietenia macrophylla) inferred from microsatellite analysis. Mol Ecol 2004; 12:2885-93. [PMID: 14629370 DOI: 10.1046/j.1365-294x.2003.01951.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
While microsatellites have been used to examine genetic structure in local populations of Neotropical trees, genetic studies based on such high-resolution markers have not been carried out for Mesoamerica as a whole. Here we assess the genetic structure of the Mesoamerican mahogany Swietenia macrophylla King (big-leaf mahogany), a Neotropical tree species recently listed as endangered in CITES which is commercially extinct through much of its native range. We used seven variable microsatellite loci to assess genetic diversity and population structure in eight naturally established mahogany populations from six Mesoamerican countries. Measures of genetic differentiation (FST and RST) indicated significant differences between most populations. Unrooted dendrograms based on genetic distances between populations provide evidence of strong phylogeographic structure in Mesoamerican mahogany. The two populations on the Pacific coasts of Costa Rica and Panama were genetically distant from all the others, and from one another. The remaining populations formed two clusters, one comprised of the northern populations of Mexico, Belize and Guatemala and the other containing the southern Atlantic populations of Nicaragua and Costa Rica. Significant correlation was found between geographical distance and all pairwise measures of genetic divergence, suggesting the importance of regional biogeography and isolation by distance in Mesoamerican mahogany. The results of this study demonstrate greater phylogeographic structure than has been found across Amazon basin S. macrophylla. Our findings suggest a relatively complex Mesoamerican biogeographic history and lead to the prediction that other Central American trees will show similar patterns of regional differentiation.
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Affiliation(s)
- Rachel Roth Novick
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT 06511, USA.
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