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Burge D. Conservation genomics and pollination biology of an endangered, edaphic-endemic, octoploid herb: El Dorado bedstraw ( Galium californicum subsp. sierrae; Rubiaceae). PeerJ 2020; 8:e10042. [PMID: 33173616 PMCID: PMC7594638 DOI: 10.7717/peerj.10042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 09/04/2020] [Indexed: 01/25/2023] Open
Abstract
El Dorado bedstraw (Galium californicum subsp. sierrae) is a federally endangered dioecious, octoploid, perennial herb found only in the Pine Hill region of El Dorado County, CA, USA. Like many species of Galium, El Dorado bedstraw is capable of both sexual and asexual reproduction, spreading via stem-layering as well as seeds. El Dorado bedstraw is also dioecious, and thus dependent on pollinators to transfer pollen from male to female stems. The capacity for asexual reproduction has conservation implications for this plant, due to the potential for populations to become dominated by a small number of clones in the absence of recruitment from seeds. No previous work has examined either the population genetics or pollination biology of this plant. Here, double-digest restriction site-associated DNA sequencing was used to develop a genetic dataset for a sample of El Dorado bedstraw (12 individuals from each of seven locations). Genomic data was used to calculate population genetic statistics and quantify the degree to which clonality affects the sampled populations. Visual observation of insect visitors at every sampling location was used to assess the potential for pollen transfer within and among locations. A total of 23 clonal colonies were detected across 82 successfully sequenced stems, consisting of an average of 2.4 individuals (range: 2–6). Significant isolation by distance among locations was detected using a Mantel test. Insect pollinators were from eleven families, consisting mainly of small species with weak flight. It is recommended that clonality and small-scale population differentiation be taken into account in conservation measures.
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Affiliation(s)
- Dylan Burge
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
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He J, Wang S, Li J, Fan Z, Liu X, Wang Y. Genetic differentiation and spatiotemporal history of diploidy and tetraploidy of Clintonia udensis. Ecol Evol 2017; 7:10243-10251. [PMID: 29238551 PMCID: PMC5723609 DOI: 10.1002/ece3.3510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 08/16/2017] [Accepted: 09/20/2017] [Indexed: 11/21/2022] Open
Abstract
Polyploidy is an important factor shaping the geographic range of a species. Clintonia udensis (Clintonia) is a primary perennial herb widely distributed in China with two karyotypic characteristics—diploid and tetraploid and thereby used to understand the ploidy and distribution. This study unraveled the patterns of genetic variation and spatiotemporal history among the cytotypes of C. udensis using simple sequence repeat or microsatellites. The results showed that the diploids and tetraploids showed the medium level of genetic differentiation; tetraploid was slightly lower than diploid in genetic diversity; recurrent polyploidization seems to have opened new possibilities for the local genotype; the spatiotemporal history of C. udensis allows tracing the interplay of polyploidy evolution; isolated and different ecological surroundings could act as evolutionary capacitors, preserve distinct karyological, and genetic diversity. The approaches of integrating genetic differentiation and spatiotemporal history of diploidy and tetraploidy of Clintonia udens would possibly provide a powerful way to understand the ploidy and plant distribution and undertaken in similar studies in other plant species simultaneously contained the diploid and tetraploid.
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Affiliation(s)
- Juan He
- College of Life Science Shanxi Normal University Linfen China
| | - Shengnan Wang
- College of Animal Science and Technology Nanjing Agricultural University Nanjing China
| | - Jia Li
- College of Life Science Shanxi Normal University Linfen China
| | - Zelu Fan
- College of Life Science Shanxi Normal University Linfen China
| | - Xin Liu
- College of Life Science Shanxi Normal University Linfen China
| | - Yiling Wang
- College of Life Science Shanxi Normal University Linfen China
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Hybridization rate and genotypic diversity of apomictic hybrids between native (Taraxacum japonicum) and introduced (T. officinale) dandelions in western Japan. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1014-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Arnau G, Bhattacharjee R, MN S, Chair H, Malapa R, Lebot V, K A, Perrier X, Petro D, Penet L, Pavis C. Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers. PLoS One 2017; 12:e0174150. [PMID: 28355293 PMCID: PMC5371318 DOI: 10.1371/journal.pone.0174150] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/03/2017] [Indexed: 11/23/2022] Open
Abstract
Yams (Dioscorea sp.) are staple food crops for millions of people in tropical and subtropical regions. Dioscorea alata, also known as greater yam, is one of the major cultivated species and most widely distributed throughout the tropics. Despite its economic and cultural importance, very little is known about its origin, diversity and genetics. As a consequence, breeding efforts for resistance to its main disease, anthracnose, have been fairly limited. The objective of this study was to contribute to the understanding of D. alata genetic diversity by genotyping 384 accessions from different geographical regions (South Pacific, Asia, Africa and the Caribbean), using 24 microsatellite markers. Diversity structuration was assessed via Principal Coordinate Analysis, UPGMA analysis and the Bayesian approach implemented in STRUCTURE. Our results revealed the existence of a wide genetic diversity and a significant structuring associated with geographic origin, ploidy levels and morpho-agronomic characteristics. Seventeen major groups of genetically close cultivars have been identified, including eleven groups of diploid cultivars, four groups of triploids and two groups of tetraploids. STRUCTURE revealed the existence of six populations in the diploid genetic pool and a few admixed cultivars. These results will be very useful for rationalizing D. alata genetic resources in breeding programs across different regions and for improving germplasm conservation methods.
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Affiliation(s)
- Gemma Arnau
- Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), Centre de Coopération International en Recherche Agronomique pour le Développement (CIRAD), Station de Roujol, Petit Bourg, Guadeloupe, France
- * E-mail: (GA); (RB)
| | - Ranjana Bhattacharjee
- Bioscience Center, International Institute of Tropical Agriculture (IITA), PMB, Ibadan, Oyo State, Nigeria
- * E-mail: (GA); (RB)
| | - Sheela MN
- Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Triruvananthapuram, India
| | - Hana Chair
- Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Montpellier, France
| | - Roger Malapa
- Vanuatu Agricultural Research and Technical Centre (VARTC), Espiritu Santo PB, Vanuatu
| | - Vincent Lebot
- Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Port-Vila, Vanuatu
| | - Abraham K
- Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Triruvananthapuram, India
| | - Xavier Perrier
- Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Montpellier, France
| | - Dalila Petro
- ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France
| | - Laurent Penet
- ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France
| | - Claudie Pavis
- ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France
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Laport RG, Minckley RL, Ramsey J. Ecological distributions, phenological isolation, and genetic structure in sympatric and parapatric populations of the Larrea tridentata polyploid complex. AMERICAN JOURNAL OF BOTANY 2016; 103:1358-1374. [PMID: 27440793 DOI: 10.3732/ajb.1600105] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 05/20/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY Polyploidy is widely recognized as a mechanism of diversification. Contributions of polyploidy to specific pre- and postzygotic barriers-and classifications of polyploid speciation as "ecological" vs. "non-ecological"-are more contentious. Evaluation of these issues requires comprehensive studies that test ecological characteristics of cytotypes as well as the coincidence of genetic structure with cytotype distributions. METHODS We investigated a classical example of autopolyploid speciation, Larrea tridentata, at multiple areas of cytotype co-occurrence. Habitat and phenological differences were compared between diploid, tetraploid, and hexaploid populations on the basis of edaphic, community composition, and flowering time surveys. Frequency of hybridization between diploids and tetraploids was investigated using a diploid-specific chloroplast DNA (cpDNA) marker; genetic structure for all cytotypes was assessed using amplified fragment length polymorphisms (AFLPs). KEY RESULTS Across contact zones, we found cytotypes in habitats distinguished by soil and vegetation. We observed modest differences in timing and production of flowers, indicating a degree of assortative mating that was asymmetric between cytotypes. Nonetheless, cpDNA analyses in diploid-tetraploid contact zones suggested that ∼5% of tetraploid plants had hybrid origins involving unilateral sexual polyploidization. Genetic structure of AFLPs largely coincided with cytotype distributions in diploid-tetraploid contact zones. In contrast, there was little structure in areas of contact between tetraploids and hexaploids, suggesting intercytotype gene flow or recurrent hexaploid formation. CONCLUSIONS Diploid, tetraploid, and hexaploid cytotypes of L. tridentata are segregated by environmental distributions and flowering phenology in contact zones, with diploid and tetraploid populations having corresponding differences in genetic structure.
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Affiliation(s)
- Robert G Laport
- University of Nebraska-Lincoln, School of Biological Sciences, Lincoln, Nebraska 68588 USA
| | - Robert L Minckley
- University of Rochester, Department of Biology, River Campus, Rochester, New York 14627 USA
| | - Justin Ramsey
- Black Hills State University, School of Natural Sciences, Spearfish, South Dakota 57799 USA
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Piedra-malagón EM, Albarrán-lara AL, Rull J, Piñero D, Sosa V. Using multiple sources of characters to delimit species in the genusCrataegus(Rosaceae): the case of theCrataegus roseicomplex. SYST BIODIVERS 2016. [DOI: 10.1080/14772000.2015.1117027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Epigenetic switch drives the conversion of fibroblasts into proinvasive cancer-associated fibroblasts. Nat Commun 2015; 6:10204. [PMID: 26667266 PMCID: PMC4682161 DOI: 10.1038/ncomms10204] [Citation(s) in RCA: 269] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 11/13/2015] [Indexed: 02/08/2023] Open
Abstract
Carcinoma-associated fibroblasts (CAF) mediate the onset of a proinvasive tumour microenvironment. The proinflammatory cytokine LIF reprograms fibroblasts into a proinvasive phenotype, which promotes extracellular matrix remodelling and collective invasion of cancer cells. Here we unveil that exposure to LIF initiates an epigenetic switch leading to the constitutive activation of JAK1/STAT3 signalling, which results in sustained proinvasive activity of CAF. Mechanistically, p300-histone acetyltransferase acetylates STAT3, which, in turn, upregulates and activates the DNMT3b DNA methyltransferase. DNMT3b methylates CpG sites of the SHP-1 phosphatase promoter, which abrogates SHP-1 expression, and results in constitutive phosphorylation of JAK1. Sustained JAK1/STAT3 signalling is maintained by DNA methyltransferase DNMT1. Consistently, in human lung and head and neck carcinomas, STAT3 acetylation and phosphorylation are inversely correlated with SHP-1 expression. Combined inhibition of DNMT activities and JAK signalling, in vitro and in vivo, results in long-term reversion of CAF-associated proinvasive activity and restoration of the wild-type fibroblast phenotype. Carcinoma-associated fibroblasts are key components of solid tumours and associated with poor clinical outcome. Here the authors show that the cytokine LIF initiates an epigenetic switch which results in the sustained invasive activity of the tumour cells.
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Wang N, Borrell JS, Bodles WJA, Kuttapitiya A, Nichols RA, Buggs RJA. Molecular footprints of the Holocene retreat of dwarf birch in Britain. Mol Ecol 2014; 23:2771-82. [PMID: 24762172 PMCID: PMC4237149 DOI: 10.1111/mec.12768] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 01/17/2023]
Abstract
Past reproductive interactions among incompletely isolated species may leave behind a trail of introgressed alleles, shedding light on historical range movements. Betula pubescens is a widespread native tetraploid tree species in Britain, occupying habitats intermediate to those of its native diploid relatives, B. pendula and B. nana. Genotyping 1134 trees from the three species at 12 microsatellite loci, we found evidence of introgression from both diploid species into B. pubescens, despite the ploidy difference. Surprisingly, introgression from B. nana, a dwarf species whose present range is highly restricted in northern, high-altitude peat bogs, was greater than introgression from B. pendula, which is morphologically similar to B. pubescens and has a substantially overlapping range. A cline of introgression from B. nana was found extending into B. pubescens populations far to the south of the current B. nana range. We suggest that this genetic pattern is a footprint of a historical decline and/or northwards shift in the range of B. nana populations due to climate warming in the Holocene. This is consistent with pollen records that show a broader, more southerly distribution of B. nana in the past. Ecological niche modelling predicts that B. nana is adapted to a larger range than it currently occupies, suggesting additional factors such as grazing and hybridization may have exacerbated its decline. We found very little introgression between B. nana and B. pendula, despite both being diploid, perhaps because their distributions in the past have rarely overlapped. Future conservation of B. nana may partly depend on minimization of hybridization with B. pubescens, and avoidance of planting B. pendula near B. nana populations.
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Affiliation(s)
- Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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Genetic diversity and differentiation of Juniperus thurifera in Spain and Morocco as determined by SSR. PLoS One 2014; 9:e88996. [PMID: 24533164 PMCID: PMC3923062 DOI: 10.1371/journal.pone.0088996] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 01/14/2014] [Indexed: 11/25/2022] Open
Abstract
Juniperus thurifera L. is an important tree endemic to the western Mediterranean basin that it is able to grow in semi-arid climates. It nowadays exhibits a disjunct distribution pattern, occurring in North Africa, Spain, France and the Italian Alps. The Strait of Gibraltar has acted as an efficient barrier against gene flow between African and European populations, which are considered different subspecies by some authors. We aimed at describing the intraspecific genetic diversity of J. thurifera in populations from the Iberian Peninsula and Morocco and the phylogeographical relationships among these populations. The ploidy level of J. thurifera was examined and eleven nuclear microsatellites (nSSRs) developed for J. thurifera were assessed for genotyping this species. Six nSSRs were polymorphic and subsequently used to assess the genetic diversity and structure of the studied populations. Genotyping of the tetraploid J. thurifera using nuclear microsatellites supports the separation of Moroccan and Spanish populations into two genetically differentiated groups that correspond to the proposed subspecies africana and thurifera. High values of within population genetic diversity were found, that accounted for 90% of the total genetic variance, while population structure was weak. The estimators of genetic diversity were higher in populations of Spain than in populations of Morocco pointing for a possible loss of genetic diversity during the spread of this species to Africa from Europe.
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Lopez L, Barreiro R. Genetic guidelines for the conservation of the endangered polyploid Centaurea borjae (Asteraceae). JOURNAL OF PLANT RESEARCH 2013; 126:81-93. [PMID: 22678690 DOI: 10.1007/s10265-012-0497-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 04/30/2012] [Indexed: 06/01/2023]
Abstract
Appropriate management of species of conservation concern requires designing strategies that should include genetic information as small population size and restricted geographic range can reduce genetic variation. We used AFLPs to investigate genetic variation within and among populations of the endangered narrow endemic Centaurea borjae, and found no evidence for genetic impoverishment despite its <40 km range and potential for vegetative propagation. Genetic variation was comparable to other plants with similar life history (88 % occurring within populations) and potential clone mates were less frequent than expected. Nonetheless, populations separated by few hundred meters showed signs of significant genetic differentiation suggesting low gene flow between them. Our results suggested that the three geographically closer populations located at the center of the range might be treated as a single management unit, while the remaining ones could be considered independent units. We found evidence of fine-scale spatial genetic structure up to 80 m indicating that the collection of germplasm for ex-situ conservation should focus on individuals separated >80 m to maximize genetic variation.
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Affiliation(s)
- Lua Lopez
- Área de Ecología, Facultad de Ciencias, Universidad da Coruña, Campus A Zapateira s/n, 15071 A Coruña, Spain.
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Abstract
Hybridisation among taxa with different ploidy levels is often associated with hybrid sterility. Clonal reproduction can stabilise these hybrids, but pervasive clonality may have a profound impact on the distribution of genetic diversity in natural populations. Here we investigate a widespread triploid taxon resulting from hybridisation between diploid Mimulus guttatus and tetraploid Mimulus luteus, two species that were introduced into the United Kingdom (UK) in the nineteenth century. This hybrid, Mimulus x robertsii, is largely sterile but capable of prolific vegetative propagation and has been recorded in the wild since 1872. We surveyed 40 Mimulus populations from localities across the UK to examine the current incidence of hybrids, and selected seventeen populations for genetic analysis using codominant markers. Cluster analyses revealed two main groups of genetically distinct individuals, corresponding to either diploid (M. guttatus) or polyploid (M. luteus and M. x robertsii) samples. Triploid hybrids were found in around 50% of sampled sites, sometimes coexisting with one of the parental species (M. guttatus). The other parent, M. luteus, was restricted to a single locality. Individual populations of M. x robertsii were genetically variable, containing multiple, highly heterozygous clones, with the majority of genetic variation distributed among- rather than within populations. Our findings demonstrate that this largely sterile, clonal taxon can preserve non-negligible amounts of genetic variation. The presence of genetically variable hybrid populations may provide the material for the continued success of asexual taxa in diverse environments.
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Absence of gene flow between diploids and hexaploids of Aster amellus at multiple spatial scales. Heredity (Edinb) 2012; 110:123-30. [PMID: 23169557 DOI: 10.1038/hdy.2012.87] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The potential for gene exchange across ploidy levels has long been recognized, but only a few studies have explored the rate of gene flow among different cytotypes. In addition, most of the existing knowledge comes from contact zones between diploids and tetraploids. The purpose of this paper was to investigate relationships between diploid and hexaploid individuals within the Aster amellus aggregate. A. amellus is known to occur in diploid and hexaploid cytotypes in Europe, with a complex contact zone in central Europe. Patterns of genetic diversity were investigated using seven microsatellite loci at three different spatial scales: (1) in the single known mixed-ploidy population; (2) in populations at the contact zone and (3) in a wider range of populations across Europe. The results show clear separation of the cytotypes at all three spatial scales. In addition, analysis of molecular variance strongly supported a model predicting a single origin of the hexaploids, with no or very limited gene flow between the cytotypes. Some hexaploid individuals found in the mixed-ploidy population, however, fell into the diploid cluster. This could suggest recurrent polyploid formation or occasional cross-pollination between cytotypes; however, there are strong post-zygotic breeding barriers between the two cytotypes, making the latter less plausible. Overall, the results suggest that the cytotypes could represent two cryptic species. Nevertheless, their formal separation is difficult as they cannot be distinguished morphologically, occupy very similar habitat conditions and have largely overlapping distribution ranges. These results show that polyploid complexes must be treated with caution as they can hide biological diversity and can have different adaptation potentials, evolving independently.
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Chen ZH, Zhang GL, Li HR, Luo JD, Li ZX, Chen GM, Yang J. A panel of five circulating microRNAs as potential biomarkers for prostate cancer. Prostate 2012; 72:1443-52. [PMID: 22298030 DOI: 10.1002/pros.22495] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 01/05/2012] [Indexed: 11/11/2022]
Abstract
BACKGROUND Circulating microRNA (miRNAs) have been shown to have the potential as noninvasive diagnosis markers in several types of cancers. In this study, we investigated whether circulating miRNAs could be used in the diagnosis of prostate cancer (CaP) in a Chinese patient population. METHODS Illumina's Human v2 miRNA microarray was used to analyze miRNAs levels in a small set of patients [25 CaP, 17 benign prostatic hyperplasia (BPH)] in an effort to identify CaP-specific miRNAs. The identified miRNAs were further examined by quantitative real-time PCR (qRT-PCR) in the same small set of patients. After the training phase of screening and selecting, the candidate miRNAs were validated in a larger independent cohort (80 CaP, 44 BPH, and 54 healthy controls) with qRT-PCR in the verification phase. RESULTS Five miRNAs were confirmed by qRT-PCR analysis in validation sets. Receiver operating characteristic (ROC) curve analysis showed all 5 miRNAs had diagnostic value. More importantly, further principal component analysis indicated component 1 extracted from expression data of the 5 miRNAs could differentiate CaP from BPH and healthy controls with high diagnosis performance, with an AUC of 0.924 and 0.860, respectively. CONCLUSIONS Our data suggested that circulating miRNAs could serve as biomarkers for CaP, and compared to single miRNA, the 5 miRNAs panel can accurately discriminate CaP from BPH and healthy controls with high sensitivity and specificity, and therefore, combined with routine PSA test, these 5 CaP-specific miRNAs may help improve CaP diagnosis in clinical application.
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Affiliation(s)
- Zhang-Hui Chen
- The First Affiliated Hospital, Zhejiang University School of Medicine, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China
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Fehlberg SD, Ferguson CJ. Intraspecific cytotypic variation and complicated genetic structure in the Phlox amabilis-P. woodhousei (Polemoniaceae) complex. AMERICAN JOURNAL OF BOTANY 2012; 99:865-874. [PMID: 22523347 DOI: 10.3732/ajb.1100540] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Polyploidy is widely recognized as an important process in the evolution of plants, but less attention has been paid to the study of intraspecific polyploidy, including its prevalence, formation, taxonomic implications, and effect on genetic diversity, structure, and gene flow within and among individuals and populations. Here we studied intraspecific ploidy level variation in the Phlox amabilis-P. woodhousei complex to determine the amount and distribution of cytotypic and genetic variation present and measure the extent of gene flow among species, cytotypes, and populations. METHODS Flow cytometry and microsatellite analyses were used to ascertain cytotypic variation, genetic diversity, and population structure within and among eight populations of P. amabilis and 10 populations of P. woodhousei from Arizona and New Mexico. KEY RESULTS Our analyses support the recognition of P. amabilis and P. woodhousei as two distinct species. Both species exhibit cytotypic variation with geographically structured diploid, tetraploid, and hexaploid populations, and genetic analyses suggest a combination of auto- and allopolyploidy in their formation. Diploid, tetraploid, and most hexaploid populations within species share much of their genetic variation, while some hexaploid populations are genetically distinct. All populations maintain moderately high genetic diversity and connectivity, and genetic structure is strongly influenced by geography. CONCLUSIONS This study highlights the potential for complicated patterns of genetic variation relative to cytotypic variation and provides evidence for the role of cytotypic variation and geographic isolation in shaping diversity, differentiation, and potentially speciation in the P. amabilis-P. woodhousei complex.
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Affiliation(s)
- Shannon D Fehlberg
- Desert Botanical Garden, 1201 North Galvin Parkway, Phoenix, Arizona 85008, USA
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Jørgensen MH, Ehrich D, Schmickl R, Koch MA, Brysting AK. Interspecific and interploidal gene flow in Central European Arabidopsis (Brassicaceae). BMC Evol Biol 2011; 11:346. [PMID: 22126410 PMCID: PMC3247304 DOI: 10.1186/1471-2148-11-346] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/29/2011] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Effects of polyploidisation on gene flow between natural populations are little known. Central European diploid and tetraploid populations of Arabidopsis arenosa and A. lyrata are here used to study interspecific and interploidal gene flow, using a combination of nuclear and plastid markers. RESULTS Ploidal levels were confirmed by flow cytometry. Network analyses clearly separated diploids according to species. Tetraploids and diploids were highly intermingled within species, and some tetraploids intermingled with the other species, as well. Isolation with migration analyses suggested interspecific introgression from tetraploid A. arenosa to tetraploid A. lyrata and vice versa, and some interploidal gene flow, which was unidirectional from diploid to tetraploid in A. arenosa and bidirectional in A. lyrata. CONCLUSIONS Interspecific genetic isolation at diploid level combined with introgression at tetraploid level indicates that polyploidy may buffer against negative consequences of interspecific hybridisation. The role of introgression in polyploid systems may, however, differ between plant species, and even within the small genus Arabidopsis, we find very different evolutionary fates when it comes to introgression.
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Affiliation(s)
- Marte H Jørgensen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
| | - Dorothee Ehrich
- Institute for Arctic and Marine Biology, University of Tromsø, NO-9037 Tromsø, Norway
| | - Roswitha Schmickl
- Centre for Organismal Studies (COS) Heidelberg, Department of Biodiversity and Plant Systematics, University of Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Marcus A Koch
- Centre for Organismal Studies (COS) Heidelberg, Department of Biodiversity and Plant Systematics, University of Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Anne K Brysting
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
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SAMPSON JANEF, BYRNE MARGARET. Genetic diversity and multiple origins of polyploid Atriplex nummularia Lindl. (Chenopodiaceae). Biol J Linn Soc Lond 2011. [DOI: 10.1111/j.1095-8312.2011.01787.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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VANDERPOORTEN A, HARDY OJ, LAMBINON J, RASPÉ O. Two reproductively isolated cytotypes and a swarm of highly inbred, disconnected populations: a glimpse into Salicornia’s evolutionary history and challenging taxonomy. J Evol Biol 2010; 24:630-44. [DOI: 10.1111/j.1420-9101.2010.02198.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Lo EYY, Stefanovic S, Ritland K, Dickinson TA. Fine-scale comparisons of genetic variability in seed families of asexually and sexually reproducing Crataegus (hawthorn; Rosaceae). AMERICAN JOURNAL OF BOTANY 2010; 97:1014-24. [PMID: 21622471 DOI: 10.3732/ajb.0900091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The reproductive system is one of the key mechanisms that determine genetic diversity at different biological levels. However, few attempts have been made to assess the consequences of asexual reproduction by comparing genetic structure and fecundity of seed families in asexually and sexually reproducing individuals. We have examined two similar hawthorn species, Crataegus crus-galli and C. punctata, that differ in ploidy level and breeding system. Fecundity (per-fruit seed set) and microsatellite genotypes for five loci were determined in 18 and 26 seed families of C. crus-galli and C. punctata (totals of 83 and 118 embryos), respectively. Compared with the sexual diploid C. punctata, tetraploid C. crus-galli shows similar fecundity, but lower genotypic diversity within and between seed families. Reproduction in the tetraploid, while predominantly apomictic, is nevertheless accompanied by outcrossing and selfing. We conclude that in C. crus-galli pollen flow between conspecific individuals is limited, and the combination of pollen fertility, self-compatibility, and pseudogamous apomixis provides reproductive assurance in these tetraploids. Reproductive assurance, in turn, may explain the derived floral architecture seen in most North American tetraploid hawthorns. We also discuss analytical approaches for inferring mating-system parameters in tetraploids and for comparing microsatellite variation across ploidy levels.
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Affiliation(s)
- Eugenia Y Y Lo
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, Connecticut 06511 USA
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Muller LAH, McCusker JH. Microsatellite analysis of genetic diversity among clinical and nonclinical Saccharomyces cerevisiae isolates suggests heterozygote advantage in clinical environments. Mol Ecol 2009; 18:2779-86. [PMID: 19457175 DOI: 10.1111/j.1365-294x.2009.04234.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The genetic structure of a global sample of 170 clinical and nonclinical Saccharomyces cerevisiae isolates was analysed using 12 microsatellite markers. High levels of genetic diversity were revealed both among the clinical and among the nonclinical S. cerevisiae isolates without significant differentiation between these two groups of isolates, rendering a single origin of pathogenic isolates unlikely. This suggests that S. cerevisiae is a true opportunistic pathogen, with a diversity of unrelated genetic backgrounds able to cause infections in humans, and that the ability of S. cerevisiae isolates to cause infections is likely due to a combination of their phenotypic plasticity and the immune system status of the exposed individuals. As was previously reported for bread, beer and wine strains and for environmental S. cerevisiae isolates, the microsatellite genotypes indicated ploidy level variation, from possibly haploid up to tetraploid, among clinical S. cerevisiae isolates. However, rather than haploid, sporulation proficiency and spore viability data indicated that most S. cerevisiae isolates that were mono-allelic at all examined microsatellite loci were likely homothallic and self-diploidized. Interestingly, the proportion of heterozygous clinical isolates was found to be significantly higher than the proportion of heterozygous nonclinical isolates, suggesting a selective advantage of heterozygous S. cerevisiae yeasts in clinical environments.
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Affiliation(s)
- Ludo A H Muller
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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García-Verdugo C, Fay MF, Granado-Yela C, DE Casas RR, Balaguer L, Besnard G, Vargas P. Genetic diversity and differentiation processes in the ploidy series of Olea europaea L.: a multiscale approach from subspecies to insular populations. Mol Ecol 2008; 18:454-67. [PMID: 19143937 DOI: 10.1111/j.1365-294x.2008.04027.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Geographical isolation and polyploidization are central concepts in plant evolution. The hierarchical organization of archipelagos in this study provides a framework for testing the evolutionary consequences for polyploid taxa and populations occurring in isolation. Using amplified fragment length polymorphism and simple sequence repeat markers, we determined the genetic diversity and differentiation patterns at three levels of geographical isolation in Olea europaea: mainland-archipelagos, islands within an archipelago, and populations within an island. At the subspecies scale, the hexaploid ssp. maroccana (southwest Morocco) exhibited higher genetic diversity than the insular counterparts. In contrast, the tetraploid ssp. cerasiformis (Madeira) displayed values similar to those obtained for the diploid ssp. guanchica (Canary Islands). Geographical isolation was associated with a high genetic differentiation at this scale. In the Canarian archipelago, the stepping-stone model of differentiation suggested in a previous study was partially supported. Within the western lineage, an east-to-west differentiation pattern was confirmed. Conversely, the easternmost populations were more related to the mainland ssp. europaea than to the western guanchica lineage. Genetic diversity across the Canarian archipelago was significantly correlated with the date of the last volcanic activity in the area/island where each population occurs. At the island scale, this pattern was not confirmed in older islands (Tenerife and Madeira), where populations were genetically homogeneous. In contrast, founder effects resulted in low genetic diversity and marked genetic differentiation among populations of the youngest island, La Palma.
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Affiliation(s)
- C García-Verdugo
- Departamento de Biología Vegetal I, Universidad Complutense de Madrid, José Antonio Novais 2, 28040 Madrid, Spain.
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