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Abhainn EA, Shirley DL, Stanley RK, Scarpato T, Koch JL, Romero-Severson J. Gene flow from Fraxinus cultivars into natural stands of Fraxinus pennsylvanica occurs range-wide, is regionally extensive, and is associated with a loss of allele richness. PLoS One 2024; 19:e0294829. [PMID: 38753718 PMCID: PMC11098341 DOI: 10.1371/journal.pone.0294829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 03/30/2024] [Indexed: 05/18/2024] Open
Abstract
In North America, a comparatively small number of Fraxinus (ash) cultivars were planted in large numbers in both urban and rural environments across the entire range of Fraxinus pennsylvanica Marsh (green ash) over the last 80 years. Undetected cultivar gene flow, if extensive, could significantly lower genetic diversity within populations, suppress differentiation between populations, generate interspecific admixture not driven by long-standing natural processes, and affect the impact of abiotic and biotic threats. In this investigation we generated the first range-wide genetic assessment of F. pennsylvanica to detect the extent of cultivar gene flow into natural stands. We used 16 EST-SSR markers to genotype 48 naturally regenerated populations of F. pennsylvanica distributed across the native range (1291 trees), 19 F. pennsylvanica cultivars, and one F. americana L. (white ash) cultivar to detect cultivar propagule dispersal into these populations. We detected first generation cultivar parentage with high confidence in 171 individuals in 34 of the 48 populations and extensive cultivar parentage (23-50%) in eight populations. The incidence of cultivar parentage was negatively associated with allele richness (R2 = 0.151, p = 0.006). The evidence for a locally high frequency of cultivar propagule dispersal and the interspecific admixture in eastern populations will inform Fraxinus gene pool conservation strategies and guide the selection of individuals for breeding programs focused on increasing resistance to the emerald ash borer (Agrilus planipennis Fairmaire), an existential threat to the Fraxinus species of North America.
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Affiliation(s)
- Everett A. Abhainn
- University of Notre Dame, Department of Biological Sciences, Notre Dame, Indiana, United States of America
| | - Devin L. Shirley
- University of Notre Dame, Department of Biological Sciences, Notre Dame, Indiana, United States of America
| | - Robert K. Stanley
- University of Notre Dame, Department of Biological Sciences, Notre Dame, Indiana, United States of America
| | - Tatum Scarpato
- University of Notre Dame, Department of Biological Sciences, Notre Dame, Indiana, United States of America
| | - Jennifer L. Koch
- USDA Forest Service, Northern Research Station, Delaware, Ohio, United States of America
| | - Jeanne Romero-Severson
- University of Notre Dame, Department of Biological Sciences, Notre Dame, Indiana, United States of America
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Tang J, Fan X, Milne RI, Yang H, Tao W, Zhang X, Guo M, Li J, Mao K. Across two phylogeographic breaks: Quaternary evolutionary history of a mountain aspen ( Populus rotundifolia) in the Hengduan Mountains. PLANT DIVERSITY 2024; 46:321-332. [PMID: 38798733 PMCID: PMC11119543 DOI: 10.1016/j.pld.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/31/2024] [Accepted: 03/31/2024] [Indexed: 05/29/2024]
Abstract
Biogeographical barriers to gene flow are central to plant phylogeography. In East Asia, plant distribution is greatly influenced by two phylogeographic breaks, the Mekong-Salween Divide and Tanaka-Kaiyong Line, however, few studies have investigated how these barriers affect the genetic diversity of species that are distributed across both. Here we used 14 microsatellite loci and four chloroplast DNA fragments to examine genetic diversity and distribution patterns of 49 populations of Populus rotundifolia, a species that spans both the Mekong-Salween Divide and the Tanaka-Kaiyong Line in southwestern China. Demographic and migration hypotheses were tested using coalescent-based approaches. Limited historical gene flow was observed between the western and eastern groups of P. rotundifolia, but substantial flow occurred across both the Mekong-Salween Divide and Tanaka-Kaiyong Line, manifesting in clear admixture and high genetic diversity in the central group. Wind-borne pollen and seeds may have facilitated the dispersal of P. rotundifolia following prevalent northwest winds in the spring. We also found that the Hengduan Mountains, where multiple genetic barriers were detected, acted on the whole as a barrier between the western and eastern groups of P. rotundifolia. Ecological niche modeling suggested that P. rotundifolia has undergone range expansion since the last glacial maximum, and demographic reconstruction indicated an earlier population expansion around 600 Ka. The phylogeographic pattern of P. rotundifolia reflects the interplay of biological traits, wind patterns, barriers, niche differentiation, and Quaternary climate history. This study emphasizes the need for multiple lines of evidence in understanding the Quaternary evolution of plants in topographically complex areas.
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Affiliation(s)
- Jieshi Tang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Xiaoyan Fan
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Richard I. Milne
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JH, UK
| | - Heng Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Wenjing Tao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Xinran Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Mengyun Guo
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Jialiang Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
| | - Kangshan Mao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, PR China
- School of Ecology and Environment, Tibet University, Lhasa 850000, PR China
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Larionov MV, Volodkin AA, Volodkina OA, Lebedev EV, Khanbabayeva OE, Tazina SV, Kozlova EA, Orlova EE, Zubik IN, Bogdanova VD, Vorobyev MV, Demidova AP, Akhmetova LR, Kondratenko YI, Goloktionov II, Soboleva EV, Gordyushkina KM. Features of the Territorial Distribution, Composition and Structure of Phytocenoses with the Participation of Fraxinus excelsior, Their Resource Qualities, Ecological and Economic Importance (Southeastern Part of the East European Plain). LIFE (BASEL, SWITZERLAND) 2022; 13:life13010093. [PMID: 36676042 PMCID: PMC9866661 DOI: 10.3390/life13010093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/31/2022]
Abstract
At present, the distribution area of Fraxinus excelsior L. in the forest ecosystems of the Volga Region is rather low and ranges from 0.01% to 2.5%. In the Middle Volga Region, using the example of the Penza region, five types of deciduous forests were identified in the composition with Fraxinus excelsior L.: oak forest aegopodium, oak forest nettle, oak forest hazel-linden, oak forest aegopodium-motley grass, oak forest carex-motley grass. In the forest phytocenoses of the Moksha River basin, the quality of Fraxinus excelsior L. is 1.5-1.7. In the forest phytocenoses of the Khoper River basin, the average quality value reaches 2.4-2.8, and in the forest tracts of the Sura river basin it is 2.8-3.2. In the western part of the study area, individuals of age class II-III (21-40, 41-60 years) predominate, in the central part-age class I (1-20 years), in the eastern part-age class V (81-100 years). This circumstance allows us to conclude that its populations in the western regions are represented by stands of different ages; the presence of young stands and middle-aged stands indicates the presence of conditions for reproduction and distribution. At the border of its range, Fraxinus excelsior L. grows in a stable population; in the western part of the Middle Volga Region, the number of species in forest stands with a predominance of Fraxinus excelsior L. is 26-30% higher than this indicator in more eastern regions. In the direction from east to west, the number of species in the composition of forest stands increases (up to 8.4), with a predominance of Fraxinus excelsior L. The number of plant associations increases in the direction from east to west. If in the east of the Penza region Fraxinus excelsior L. occurs in 6-7 plant associations, then in the west of the region-in 18-25 associations. The maximum timber stock for 100 years of Fraxinus excelsior L. stands reaches 380 m3/ha. Such a natural bioresource potential is of importance for the conduct of the national economy. Forest management in phytocenoses with the participation of this tree species is a strategic branch direction. It is expedient to restore populations of Fraxinus excelsior L. everywhere and to cultivate them in the territory of the East European Plain and especially in its south-eastern part. This is fully consistent with the principles of sustainable ecological and economic development against the background of local natural, climatic and geographical conditions. This type is necessary when solving environmental, resource-saving and economic problems in the territory under consideration.
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Affiliation(s)
- Maxim Viktorovich Larionov
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
- Faculty of Ecology and Environmental Protection, Russian State Social University (RSSU), 4 Wilhelm Peak Street, Building 1, 129226 Moscow, Russia
- State University of Management (SUM), 99 Ryazanskij Prospect Street, 109542 Moscow, Russia
- Federal State Budgetary Educational Institution of Higher Education “State University of Land Use Planning” (SULUP), 15 Kazakov Street, 105064 Moscow, Russia
- Correspondence: or ; Tel.: +7-9096613318
| | - Alexey Anatolievich Volodkin
- Department “Crop Production and Forestry”, Penza State Agrarian University, 30 Botanicheskaja Street, 440014 Penza, Russia
| | - Olga Alexandrovna Volodkina
- Department “Crop Production and Forestry”, Penza State Agrarian University, 30 Botanicheskaja Street, 440014 Penza, Russia
| | - Evgeny Valentinovich Lebedev
- Department “Forest Inventory and Forest Management”, Nizhny Novgorod State Agricultural Academy, 97 Gagarin Avenue, 603107 Nizhny Novgorod, Russia
| | - Olga Evgenievna Khanbabayeva
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Svetlana Vitalievna Tazina
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Elena Anatolyevna Kozlova
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Elena Evgenievna Orlova
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Inna Nikolaevna Zubik
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Varvara Dmitrievna Bogdanova
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Mikhail Vladimirovich Vorobyev
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Alena Pavlovna Demidova
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Liliya Rafisovna Akhmetova
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Yulia Igorevna Kondratenko
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
| | - Ivan Ivanovich Goloktionov
- Moscow Timiryazev Agricultural Academy—Russian State Agrarian University, 49 Timiryazevskaya Street, 127550 Moscow, Russia
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Crotti M, Adams CE, Etheridge EC, Bean CW, Gowans ARD, Knudsen R, Lyle AA, Maitland PS, Winfield IJ, Elmer KR, Præbel K. Geographic hierarchical population genetic structuring in British European whitefish (Coregonus lavaretus) and its implications for conservation. CONSERV GENET 2020. [DOI: 10.1007/s10592-020-01298-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractThe European whitefish Coregonus lavaretus complex represents one of the most diverse radiations within salmonids, with extreme morphological and genetic differentiation across its range. Such variation has led to the assignment of many populations to separate species. In Great Britain, the seven native populations of C. lavaretus (two in Scotland, four in England, one in Wales) were previously classified into three species, and recent taxonomic revision resurrected the previous nomenclature. Here we used a dataset of 15 microsatellites to: (1) investigate the genetic diversity of British populations, (2) assess the level of population structure and the relationships between British populations. Genetic diversity was highest in Welsh (HO = 0.50, AR = 5.29), intermediate in English (HO = 0.41–0.50, AR = 2.83–3.88), and lowest in Scottish populations (HO = 0.28–0.35, AR = 2.56–3.04). Population structure analyses indicated high genetic differentiation (global FST = 0.388) between all populations but for the two Scottish populations (FST = 0.063) and two English populations (FST = 0.038). Principal component analysis and molecular ANOVA revealed separation between Scottish, English, and Welsh populations, with the Scottish populations being the most diverged. We argue that the data presented here are not sufficient to support a separation of the British European whitefish populations into three separate species, but support the delineation of different ESUs for these populations.
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DNA analysis of Castanea sativa (sweet chestnut) in Britain and Ireland: Elucidating European origins and genepool diversity. PLoS One 2019; 14:e0222936. [PMID: 31553775 PMCID: PMC6760806 DOI: 10.1371/journal.pone.0222936] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 09/10/2019] [Indexed: 11/20/2022] Open
Abstract
Castanea sativa is classified as non-indigenous in Britain and Ireland. It was long held that it was first introduced into Britain by the Romans, until a recent study found no corroborative evidence of its growing here before c. AD 650. This paper presents new data on the genetic diversity of C. sativa in Britain and Ireland and potential ancestral sources in continental Europe. Microsatellite markers and analytical methods tested in previous European studies were used to genotype over 600 C. sativa trees and coppice stools, sampled from ancient semi-natural woodlands, secondary woodlands and historic cultural sites across Britain and Ireland. A single overall genepool with a diverse admixture of genotypes was found, containing two sub groups differentiating Wales from Ireland, with discrete geographical and typological clusters. C. sativa genotypes in Britain and Ireland were found to relate predominantly to some sites in Portugal, Spain, France, Italy and Romania, but not to Greece, Turkey or eastern parts of Europe. C. sativa has come to Britain and Ireland from these western European areas, which had acted as refugia in the Last Glacial Maximum; we compare its introduction with the colonization/translocation of oak, ash, beech and hazel into Britain and Ireland. Clones of C. sativa were identified in Britain, defining for the first time the antiquity of some ancient trees and coppice stools, evincing both natural regeneration and anthropogenic propagation over many centuries and informing the chronology of the species’ arrival in Britain. This new evidence on the origins and antiquity of British and Irish C. sativa trees enhances their conservation and economic significance, important in the context of increasing threats from environmental change, pests and pathogens.
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Erichsen EO, Budde KB, Sagheb-Talebi K, Bagnoli F, Vendramin GG, Hansen OK. Hyrcanian forests-Stable rear-edge populations harbouring high genetic diversity of Fraxinus excelsior,
a common European tree species. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12783] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Eva Ortvald Erichsen
- Department of Geosciences and Natural Resource Management; University of Copenhagen; Frederiksberg Denmark
| | - Katharina Birgit Budde
- Department of Geosciences and Natural Resource Management; University of Copenhagen; Frederiksberg Denmark
| | - Khosro Sagheb-Talebi
- Research Institute of Forests & Rangelands; Agricultural Research, Education and Extension Organization (AREEO); Tehran Iran
| | - Francesca Bagnoli
- Institute of Biosciences and Bioresources; National Research Council; Sesto Fiorentino (Firenze) Italy
| | | | - Ole Kim Hansen
- Department of Geosciences and Natural Resource Management; University of Copenhagen; Frederiksberg Denmark
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Optimizing Conservation Strategies for a Threatened Tree Species: In Situ Conservation of White Ash (Fraxinus americana L.) Genetic Diversity through Insecticide Treatment. FORESTS 2018. [DOI: 10.3390/f9040202] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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A first assessment of Fraxinus excelsior (common ash) susceptibility to Hymenoscyphus fraxineus (ash dieback) throughout the British Isles. Sci Rep 2017; 7:16546. [PMID: 29185457 PMCID: PMC5707348 DOI: 10.1038/s41598-017-16706-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/22/2017] [Indexed: 01/15/2023] Open
Abstract
Ash dieback (ADB), caused by Hymenoscyphus fraxineus, has severely damaged a large proportion of ash trees (Fraxinus excelsior) in continental Europe. We have little damage data for the British Isles where the disease was found only five years ago in the Southeast, and is still spreading. A large-scale screening trial to evaluate ADB damage to provenances of F. excelsior sourced from throughout the British Isles was planted in 2013 in the southeast of England. In 2016, we scored trees by their level of ADB damage observed in field at the two worst affected (based on assessments in 2015) of the 14 sites. Significant differences were found in average ADB damage among planting sites and seed source provenances. Trees from certain provenances in Scotland were the least damaged by ADB, whereas trees from Wales and Southeast England were the most badly damaged in both trial sites. Thus the levels of ADB damage currently seen in ash populations in Southeast England may not be an accurate predictor of the damage expected in future throughout the British Isles. Given all provenances contained some healthy trees, a breeding programme to produce genetically variable native ash tree populations with lower ADB susceptibility may be feasible.
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Affiliation(s)
- J. Allan Downie
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
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Chen C, Lu RS, Zhu SS, Tamaki I, Qiu YX. Population structure and historical demography of Dipteronia dyeriana (Sapindaceae), an extremely narrow palaeoendemic plant from China: implications for conservation in a biodiversity hot spot. Heredity (Edinb) 2017; 119:95-106. [PMID: 28379211 DOI: 10.1038/hdy.2017.19] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 11/09/2022] Open
Abstract
Inferring past demography is a central question in evolutionary and conservation biology. It is, however, sometimes challenging to disentangle their roles of contemporary versus historical processes in shaping the current patterns of genetic variation in endangered species. In this study, we used both chloroplast microsatellite (cpSSR) loci and nuclear microsatellite (nSSR) loci to assess the levels of genetic differentiation, genetic effective population size, contemporary/historical levels of gene flow and demographic history for five populations sampled across the range of Dipteronia dyeriana, an endangered palaeoendemism from Southwestern China. We found that D. dyeriana had a mixed pattern of moderate genetic diversity and high inbreeding. Bayesian clustering divided D. dyeriana populations into two nSSR genetic clusters. Coalescent-based approximate Bayesian computation analyses suggest the western and eastern groups of D. dyeriana likely persisted in a long-term refuge in Southern China since the beginning of the last glacial period, whereas increasingly colder and arid climates at the onset of the last glacial maximum might have fostered the fragmentation of D. dyeriana within refugia. Following their divergence, the western group kept relatively stable effective population size, whereas the eastern group had experienced 500-fold population expansion during the Holocene. Although clear loss of genetic diversity by human activities was not suggested, recent habitat fragmentation has led to a reduction of population connectivity and increased genetic differentiation by ongoing genetic drift in isolated populations, possibly owing to decreased population size in recent dozen years. Finally, we discussed the implications of these results on conservation policies.
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Affiliation(s)
- C Chen
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China.,College of Life Sciences, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - R S Lu
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - S S Zhu
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - I Tamaki
- Gifu Academy of Forest Science and Culture, Mino, Japan
| | - Y X Qiu
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China
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Genetic Structure in the Northern Range Margins of Common Ash, Fraxinus excelsior L. PLoS One 2016; 11:e0167104. [PMID: 27907032 PMCID: PMC5132317 DOI: 10.1371/journal.pone.0167104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/07/2016] [Indexed: 12/29/2022] Open
Abstract
During post glacial colonization, loss of genetic diversity due to leading edge effects may be attenuated in forest trees because of their prolonged juvenile phase, allowing many migrants to reach the colonizing front before populations become reproductive. The northern range margins of temperate tree taxa in Europe are particularly suitable to study the genetic processes that follow colonization because they have been little affected by northern refugia. Here we examined how post glacial range dynamics have shaped the genetic structure of common ash (Fraxinus excelsior L.) in its northern range compared to its central range in Europe. We used four chloroplast and six nuclear microsatellites to screen 42 populations (1099 trees), half of which corresponded to newly sampled populations in the northern range and half of which represented reference populations from the central range obtained from previously studies. We found that northern range populations of common ash have the same chloroplast haplotypes as south-eastern European populations, suggesting that colonization of the northern range took place along a single migration route, a result confirmed by the structure at the nuclear microsatellites. Along this route, diversity strongly decreased only in the northern range, concomitantly with increasing population differentiation and complex population substructures, a pattern consistent with a leading edge colonization model. Our study highlights that while diversity is maintained in the central range of common ash due to broad colonizing fronts and high levels of gene flow, it profoundly decreases in the northern range, where colonization was unidirectional and probably involved repeated founder events and population fluctuations. Currently, common ash is threatened by ash dieback, and our results on northern populations will be valuable for developing gene conservation strategies.
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Tsuda Y, Nakao K, Ide Y, Tsumura Y. The population demography ofBetula maximowicziana, a cool-temperate tree species in Japan, in relation to the last glacial period: its admixture-like genetic structure is the result of simple population splitting not admixing. Mol Ecol 2015; 24:1403-18. [DOI: 10.1111/mec.13123] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Y. Tsuda
- Program in Plant Ecology and Evolution; Department of Ecology and Genetics; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18D 75236 Uppsala Sweden
- Department of Forest Genetics; Forestry and Forest Products Research Institute (FFPRI); Matsunosato 1 Tsukuba Ibaraki 305-8687 Japan
| | - K. Nakao
- Department of Plant Ecology; Forestry and Forest Products Research Institute (FFPRI); Matsunosato 1 Tsukubaa Ibaraki 305-8687 Japan
| | - Y. Ide
- Laboratory of Forest Ecosystem Studies; Department of Ecosystem Studies; Graduate School of Agriculture and Life Sciences; The University of Tokyo; Yayoi 1-1-1 Bunkyo-ku Tokyo 113-8657 Japan
| | - Y. Tsumura
- Department of Forest Genetics; Forestry and Forest Products Research Institute (FFPRI); Matsunosato 1 Tsukuba Ibaraki 305-8687 Japan
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Bodare S, Tsuda Y, Ravikanth G, Uma Shaanker R, Lascoux M. Genetic structure and demographic history of the endangered tree species Dysoxylum malabaricum (Meliaceae) in Western Ghats, India: implications for conservation in a biodiversity hotspot. Ecol Evol 2013; 3:3233-48. [PMID: 24223264 PMCID: PMC3797473 DOI: 10.1002/ece3.669] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 12/02/2022] Open
Abstract
The impact of fragmentation by human activities on genetic diversity of forest trees is an important concern in forest conservation, especially in tropical forests. Dysoxylum malabaricum (white cedar) is an economically important tree species, endemic to the Western Ghats, India, one of the world's eight most important biodiversity hotspots. As D. malabaricum is under pressure of disturbance and fragmentation together with overharvesting, conservation efforts are required in this species. In this study, range-wide genetic structure of twelve D. malabaricum populations was evaluated to assess the impact of human activities on genetic diversity and infer the species’ evolutionary history, using both nuclear and chloroplast (cp) DNA simple sequence repeats (SSR). As genetic diversity and population structure did not differ among seedling, juvenile and adult age classes, reproductive success among the old-growth trees and long distance seed dispersal by hornbills were suggested to contribute to maintain genetic diversity. The fixation index (FIS) was significantly correlated with latitude, with a higher level of inbreeding in the northern populations, possibly reflecting a more severe ecosystem disturbance in those populations. Both nuclear and cpSSRs revealed northern and southern genetic groups with some discordance of their distributions; however, they did not correlate with any of the two geographic gaps known as genetic barriers to animals. Approximate Bayesian computation-based inference from nuclear SSRs suggested that population divergence occurred before the last glacial maximum. Finally we discussed the implications of these results, in particular the presence of a clear pattern of historical genetic subdivision, on conservation policies.
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Affiliation(s)
- Sofia Bodare
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University Norbyvägen 18D, 75236 Uppsala, Sweden
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Temunović M, Franjić J, Satovic Z, Grgurev M, Frascaria-Lacoste N, Fernández-Manjarrés JF. Environmental heterogeneity explains the genetic structure of Continental and Mediterranean populations of Fraxinus angustifolia Vahl. PLoS One 2012; 7:e42764. [PMID: 22905171 PMCID: PMC3414449 DOI: 10.1371/journal.pone.0042764] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/12/2012] [Indexed: 11/18/2022] Open
Abstract
Tree species with wide distributions often exhibit different levels of genetic structuring correlated to their environment. However, understanding how environmental heterogeneity influences genetic variation is difficult because the effects of gene flow, drift and selection are confounded. We investigated the genetic variation and its ecological correlates in a wind-pollinated Mediterranean tree species, Fraxinus angustifolia Vahl, within a recognised glacial refugium in Croatia. We sampled 11 populations from environmentally divergent habitats within the Continental and Mediterranean biogeographical regions. We combined genetic data analyses based on nuclear microsatellite loci, multivariate statistics on environmental data and ecological niche modelling (ENM). We identified a geographic structure with a high genetic diversity and low differentiation in the Continental region, which contrasted with the significantly lower genetic diversity and higher population divergence in the Mediterranean region. The positive and significant correlation between environmental and genetic distances after controlling for geographic distance suggests an important influence of ecological divergence of the sites in shaping genetic variation. The ENM provided support for niche differentiation between the populations from the Continental and Mediterranean regions, suggesting that contemporary populations may represent two divergent ecotypes. Ecotype differentiation was also supported by multivariate environmental and genetic distance analyses. Our results suggest that despite extensive gene flow in continental areas, long-term stability of heterogeneous environments have likely promoted genetic divergence of ashes in this region and can explain the present-day genetic variation patterns of these ancient populations.
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Affiliation(s)
- Martina Temunović
- Department of Forest Genetics, Faculty of Forestry, University of Zagreb, Zagreb, Croatia.
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Shi MM, Chen XY. Leading-edge populations do not show low genetic diversity or high differentiation in a wind-pollinated tree. POPUL ECOL 2012. [DOI: 10.1007/s10144-012-0332-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cullingham CI, James PMA, Cooke JEK, Coltman DW. Characterizing the physical and genetic structure of the lodgepole pine × jack pine hybrid zone: mosaic structure and differential introgression. Evol Appl 2012; 5:879-91. [PMID: 23346232 PMCID: PMC3552405 DOI: 10.1111/j.1752-4571.2012.00266.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 04/08/2012] [Indexed: 01/07/2023] Open
Abstract
Understanding the physical and genetic structure of hybrid zones can illuminate factors affecting their formation and stability. In north-central Alberta, lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia) and jack pine (Pinus banksiana Lamb) form a complex and poorly defined hybrid zone. Better knowledge of this zone is relevant, given the recent host expansion of mountain pine beetle into jack pine. We characterized the zone by genotyping 1998 lodgepole, jack pine, and hybrids from British Columbia, Alberta, Saskatchewan, Ontario, and Minnesota at 11 microsatellites. Using Bayesian algorithms, we calculated genetic ancestry and used this to model the relationship between species occurrence and environment. In addition, we analyzed the ancestry of hybrids to calculate the genetic contribution of lodgepole and jack pine. Finally, we measured the amount of gene flow between the pure species. We found the distribution of the pine classes is explained by environmental variables, and these distributions differ from classic distribution maps. Hybrid ancestry was biased toward lodgepole pine; however, gene flow between the two species was equal. The results of this study suggest that the hybrid zone is complex and influenced by environmental constraints. As a result of this analysis, range limits should be redefined.
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