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Chen SH, Rossetto M, van der Merwe M, Lu-Irving P, Yap JYS, Sauquet H, Bourke G, Amos TG, Bragg JG, Edwards RJ. Chromosome-level de novo genome assembly of Telopea speciosissima (New South Wales waratah) using long-reads, linked-reads and Hi-C. Mol Ecol Resour 2022; 22:1836-1854. [PMID: 35016262 DOI: 10.1111/1755-0998.13574] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 11/29/2022]
Abstract
Telopea speciosissima, the New South Wales waratah, is an Australian endemic woody shrub in the family Proteaceae. Waratahs have great potential as a model clade to better understand processes of speciation, introgression and adaptation, and are significant from a horticultural perspective. Here, we report the first chromosome-level genome for T. speciosissima. Combining Oxford Nanopore long-reads, 10x Genomics Chromium linked-reads and Hi-C data, the assembly spans 823 Mb (scaffold N50 of 69.0 Mb) with 97.8% of Embryophyta BUSCOs "Complete". We present a new method in Diploidocus (https://github.com/slimsuite/diploidocus) for classifying, curating and QC-filtering scaffolds, which combines read depths, k-mer frequencies and BUSCO predictions. We also present a new tool, DepthSizer (https://github.com/slimsuite/depthsizer), for genome size estimation from the read depth of single-copy orthologues and estimate the genome size to be approximately 900 Mb. The largest 11 scaffolds contained 94.1% of the assembly, conforming to the expected number of chromosomes (2n = 22). Genome annotation predicted 40,158 protein-coding genes, 351 rRNAs and 728 tRNAs. We investigated CYCLOIDEA (CYC) genes, which have a role in determination of floral symmetry, and confirm the presence of two copies in the genome. Read depth analysis of 180 "Duplicated" BUSCO genes using a new tool, DepthKopy (https://github.com/slimsuite/depthkopy), suggests almost all are real duplications, increasing confidence in the annotation and highlighting a possible need to revise the BUSCO set for this lineage. The chromosome-level T. speciosissima reference genome (Tspe_v1) provides an important new genomic resource of Proteaceae to support the conservation of flora in Australia and further afield.
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Affiliation(s)
- Stephanie H Chen
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, New South Wales, Australia.,Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia
| | - Maurizio Rossetto
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia.,Queensland Alliance of Agriculture and Food Innovation, University of Queensland, St Lucia, Queensland, Australia
| | - Marlien van der Merwe
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia
| | - Patricia Lu-Irving
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia
| | - Jia-Yee S Yap
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia.,Queensland Alliance of Agriculture and Food Innovation, University of Queensland, St Lucia, Queensland, Australia
| | - Hervé Sauquet
- National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Sydney, New South Wales, Australia.,School of Biological, Earth and Environmental Sciences, UNSW Sydney, New South Wales, Australia
| | - Greg Bourke
- Blue Mountains Botanic Garden, Mount Tomah, New South Wales, Australia
| | - Timothy G Amos
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, New South Wales, Australia
| | - Jason G Bragg
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, The Royal Botanic Garden Sydney, Sydney, New South Wales, Australia.,School of Biological, Earth and Environmental Sciences, UNSW Sydney, New South Wales, Australia
| | - Richard J Edwards
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, New South Wales, Australia
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2
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Sherwin WB, Chao A, Jost L, Smouse PE. Information Theory Broadens the Spectrum of Molecular Ecology and Evolution. Trends Ecol Evol 2017; 32:948-963. [PMID: 29126564 DOI: 10.1016/j.tree.2017.09.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 01/18/2023]
Abstract
Information or entropy analysis of diversity is used extensively in community ecology, and has recently been exploited for prediction and analysis in molecular ecology and evolution. Information measures belong to a spectrum (or q profile) of measures whose contrasting properties provide a rich summary of diversity, including allelic richness (q=0), Shannon information (q=1), and heterozygosity (q=2). We present the merits of information measures for describing and forecasting molecular variation within and among groups, comparing forecasts with data, and evaluating underlying processes such as dispersal. Importantly, information measures directly link causal processes and divergence outcomes, have straightforward relationship to allele frequency differences (including monotonicity that q=2 lacks), and show additivity across hierarchical layers such as ecology, behaviour, cellular processes, and nongenetic inheritance.
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Affiliation(s)
- W B Sherwin
- Evolution and Ecology Research Centre, School of Biological Earth and Environmental Science, University of New South Wales, Sydney, NSW 2052, Australia; Murdoch University Cetacean Research Unit, Murdoch University, South Road, Murdoch, WA 6150, Australia.
| | - A Chao
- Institute of Statistics, National Tsing Hua University, Hsin-Chu 30043, Taiwan
| | - L Jost
- EcoMinga Foundation, Via a Runtun, Baños, Tungurahua, Ecuador
| | - P E Smouse
- Department of Ecology, Evolution and Natural Resources, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901-8551, USA
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3
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Caddy-Retalic S, Andersen AN, Aspinwall MJ, Breed MF, Byrne M, Christmas MJ, Dong N, Evans BJ, Fordham DA, Guerin GR, Hoffmann AA, Hughes AC, van Leeuwen SJ, McInerney FA, Prober SM, Rossetto M, Rymer PD, Steane DA, Wardle GM, Lowe AJ. Bioclimatic transect networks: Powerful observatories of ecological change. Ecol Evol 2017; 7:4607-4619. [PMID: 28690791 PMCID: PMC5496522 DOI: 10.1002/ece3.2995] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 03/21/2017] [Indexed: 01/02/2023] Open
Abstract
Transects that traverse substantial climate gradients are important tools for climate change research and allow questions on the extent to which phenotypic variation associates with climate, the link between climate and species distributions, and variation in sensitivity to climate change among biomes to be addressed. However, the potential limitations of individual transect studies have recently been highlighted. Here, we argue that replicating and networking transects, along with the introduction of experimental treatments, addresses these concerns. Transect networks provide cost‐effective and robust insights into ecological and evolutionary adaptation and improve forecasting of ecosystem change. We draw on the experience and research facilitated by the Australian Transect Network to demonstrate our case, with examples, to clarify how population‐ and community‐level studies can be integrated with observations from multiple transects, manipulative experiments, genomics, and ecological modeling to gain novel insights into how species and systems respond to climate change. This integration can provide a spatiotemporal understanding of past and future climate‐induced changes, which will inform effective management actions for promoting biodiversity resilience.
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Affiliation(s)
- Stefan Caddy-Retalic
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
| | - Alan N Andersen
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,Charles Darwin University Darwin NT Australia
| | - Michael J Aspinwall
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,Hawkesbury Institute for the Environment Western Sydney University Parramatta NSW Australia
| | - Martin F Breed
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
| | - Margaret Byrne
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,Science and Conservation Division Western Australian Department of Parks and Wildlife Kensington WA Australia
| | - Matthew J Christmas
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
| | - Ning Dong
- Department of Biological Sciences Macquarie University North Ryde NSW Australia.,Ecosystem Modelling and Scaling Infrastructure Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia
| | - Bradley J Evans
- Ecosystem Modelling and Scaling Infrastructure Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - Damien A Fordham
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
| | - Greg R Guerin
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
| | - Ary A Hoffmann
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of BioSciences, Bio 21 InstituteThe University of Melbourne Parkville VIC Australia
| | - Alice C Hughes
- Centre for Integrative Conservation Xishuangbanna Tropical Botanic Garden Chinese Academy of Sciences Menglun, Mengla County Yunnan China
| | - Stephen J van Leeuwen
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,Science and Conservation Division Western Australian Department of Parks and Wildlife Kensington WA Australia
| | - Francesca A McInerney
- Sprigg Geobiology Centre and School of Physical Sciences University of Adelaide Adelaide SA Australia
| | - Suzanne M Prober
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,CSIRO Land and Water Wembley WA Australia
| | - Maurizio Rossetto
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,National Herbarium of NSW Royal Botanic Gardens and Domain Trust Sydney NSW Australia
| | - Paul D Rymer
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,Hawkesbury Institute for the Environment Western Sydney University Parramatta NSW Australia
| | - Dorothy A Steane
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,CSIRO Land and Water Wembley WA Australia.,School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania 7001 Australia.,Faculty of Science, Health, Education and Engineering University of the Sunshine Coast Maroochydore QLD Australia
| | - Glenda M Wardle
- School Life and Environmental Sciences University of Sydney Sydney NSW Australia.,Long Term Ecological Research Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia
| | - Andrew J Lowe
- Australian Transect Network Terrestrial Ecosystem Research Network (TERN) Adelaide SA Australia.,School of Biological Sciences and Environment InstituteUniversity of Adelaide Adelaide SA Australia
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4
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Huang G, Rymer PD, Duan H, Smith RA, Tissue DT. Elevated temperature is more effective than elevated [CO2 ] in exposing genotypic variation in Telopea speciosissima growth plasticity: implications for woody plant populations under climate change. GLOBAL CHANGE BIOLOGY 2015; 21:3800-13. [PMID: 26033432 DOI: 10.1111/gcb.12990] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/28/2015] [Indexed: 05/26/2023]
Abstract
Intraspecific variation in phenotypic plasticity is a critical determinant of plant species capacity to cope with climate change. A long-standing hypothesis states that greater levels of environmental variability will select for genotypes with greater phenotypic plasticity. However, few studies have examined how genotypes of woody species originating from contrasting environments respond to multiple climate change factors. Here, we investigated the main and interactive effects of elevated [CO2 ] (CE ) and elevated temperature (TE ) on growth and physiology of Coastal (warmer, less variable temperature environment) and Upland (cooler, more variable temperature environment) genotypes of an Australian woody species Telopea speciosissima. Both genotypes were positively responsive to CE (35% and 29% increase in whole-plant dry mass and leaf area, respectively), but only the Coastal genotype exhibited positive growth responses to TE . We found that the Coastal genotype exhibited greater growth response to TE (47% and 85% increase in whole-plant dry mass and leaf area, respectively) when compared with the Upland genotype (no change in dry mass or leaf area). No intraspecific variation in physiological plasticity was detected under CE or TE , and the interactive effects of CE and TE on intraspecific variation in phenotypic plasticity were also largely absent. Overall, TE was a more effective climate factor than CE in exposing genotypic variation in our woody species. Our results contradict the paradigm that genotypes from more variable climates will exhibit greater phenotypic plasticity in future climate regimes.
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Affiliation(s)
- Guomin Huang
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
| | - Honglang Duan
- Institute of Ecology & Environmental Science, Nanchang Institute of Technology, Nanchang, Jiangxi, 330099, China
| | - Renee A Smith
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
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5
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Expected Shannon Entropy and Shannon Differentiation between Subpopulations for Neutral Genes under the Finite Island Model. PLoS One 2015; 10:e0125471. [PMID: 26067448 PMCID: PMC4465833 DOI: 10.1371/journal.pone.0125471] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 03/24/2015] [Indexed: 01/21/2023] Open
Abstract
Shannon entropy H and related measures are increasingly used in molecular ecology and population genetics because (1) unlike measures based on heterozygosity or allele number, these measures weigh alleles in proportion to their population fraction, thus capturing a previously-ignored aspect of allele frequency distributions that may be important in many applications; (2) these measures connect directly to the rich predictive mathematics of information theory; (3) Shannon entropy is completely additive and has an explicitly hierarchical nature; and (4) Shannon entropy-based differentiation measures obey strong monotonicity properties that heterozygosity-based measures lack. We derive simple new expressions for the expected values of the Shannon entropy of the equilibrium allele distribution at a neutral locus in a single isolated population under two models of mutation: the infinite allele model and the stepwise mutation model. Surprisingly, this complex stochastic system for each model has an entropy expressable as a simple combination of well-known mathematical functions. Moreover, entropy- and heterozygosity-based measures for each model are linked by simple relationships that are shown by simulations to be approximately valid even far from equilibrium. We also identify a bridge between the two models of mutation. We apply our approach to subdivided populations which follow the finite island model, obtaining the Shannon entropy of the equilibrium allele distributions of the subpopulations and of the total population. We also derive the expected mutual information and normalized mutual information ("Shannon differentiation") between subpopulations at equilibrium, and identify the model parameters that determine them. We apply our measures to data from the common starling (Sturnus vulgaris) in Australia. Our measures provide a test for neutrality that is robust to violations of equilibrium assumptions, as verified on real world data from starlings.
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6
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Hoffmann A, Griffin P, Dillon S, Catullo R, Rane R, Byrne M, Jordan R, Oakeshott J, Weeks A, Joseph L, Lockhart P, Borevitz J, Sgrò C. A framework for incorporating evolutionary genomics into biodiversity conservation and management. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/s40665-014-0009-x] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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7
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McIntosh EJ, Rossetto M, Weston PH, Wardle GM. Maintenance of strong morphological differentiation despite ongoing natural hybridization between sympatric species of Lomatia (Proteaceae). ANNALS OF BOTANY 2014; 113:861-872. [PMID: 24489011 PMCID: PMC3962242 DOI: 10.1093/aob/mct314] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 12/13/2013] [Indexed: 06/03/2023]
Abstract
BACKGROUND AND AIMS When species cohesion is maintained despite ongoing natural hybridization, many questions are raised about the evolutionary processes operating in the species complex. This study examined the extensive natural hybridization between the Australian native shrubs Lomatia myricoides and L. silaifolia (Proteaceae). These species exhibit striking differences in morphology and ecological preferences, exceeding those found in most studies of hybridization to date. METHODS Nuclear microsatellite markers (nSSRs), genotyping methods and morphometric analyses were used to uncover patterns of hybridization and the role of gene flow in morphological differentiation between sympatric species. KEY RESULTS The complexity of hybridization patterns differed markedly between sites, however, signals of introgression were present at all sites. One site provided evidence of a large hybrid swarm and the likely presence of multiple hybrid generations and backcrosses, another site a handful of early generational hybrids and a third site only traces of admixture from a past hybridization event. The presence of cryptic hybrids and a pattern of morphological bimodality amongst hybrids often disguised the extent of underlying genetic admixture. CONCLUSIONS Distinct parental habitats and phenotypes are expected to form barriers that contribute to the rapid reversion of hybrid populations to their parental character state, due to limited opportunities for hybrid/intermediate advantage. Furthermore, strong genomic filters may facilitate continued gene flow between species without the danger of assimilation. Stochastic fire events facilitate temporal phenological isolation between species and may partly explain the bi-directional and site-specific patterns of hybridization observed. Furthermore, the findings suggest that F1 hybrids are rare, and backcrosses may occur rapidly following these initial hybridization events.
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Affiliation(s)
- Emma J. McIntosh
- The Royal Botanic Gardens and Domain Trust, Sydney, New South Wales, Australia
- School of Biological Sciences, the University of Sydney, Sydney, New South Wales, Australia
| | - Maurizio Rossetto
- The Royal Botanic Gardens and Domain Trust, Sydney, New South Wales, Australia
| | - Peter H. Weston
- The Royal Botanic Gardens and Domain Trust, Sydney, New South Wales, Australia
| | - Glenda M. Wardle
- School of Biological Sciences, the University of Sydney, Sydney, New South Wales, Australia
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8
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Weston PH. What has molecular systematics contributed to our knowledge of the plant family Proteaceae? Methods Mol Biol 2014; 1115:365-97. [PMID: 24415484 DOI: 10.1007/978-1-62703-767-9_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular systematics has revolutionized our understanding of the evolution of the Proteaceae. Phylogenetic relationships have been reconstructed down to generic level and below from alignments of chloroplast and nuclear DNA sequences. These trees have enabled the monophyly of all subfamilies, tribes, and subtribes to be rigorously tested and the construction of a new classification of the family at these ranks. Molecular data have also played a major part in testing the monophyly of genera and infrageneric taxa, some of which have been recircumscribed as a result. Molecular trees and chronograms have been used to test numerous previously postulated biogeographic and evolutionary hypotheses, some of which have been modified or abandoned as a result. Hypotheses that have been supported by molecular phylogenetic trees and chronograms include the following: that the proteaceous pattern of repeated disjunct distributions across the southern hemisphere is partly the result of long-distance dispersal; that high proteaceous diversity in south-western Australia and the Cape Floristic Region of South Africa is due to high diversification rates in some clades but is not an evolutionary response to Mediterranean climates; that the sclerophyllous leaves of many shrubby members of the family are not adaptations to dry environments but for protecting mesophyll in brightly illuminated habitats; that deeply encrypted foliar stomata are adaptations for minimizing water loss in dry environments; and that Protea originated in the Cape Floristic Region of South Africa and that one of its subclades has greatly expanded its distribution into tropical savannas. Reconstructing phylogeny down to species level is now the main goal of molecular systematists of the Proteaceae. The biggest challenge in achieving this task will be resolving species trees from numerous gene trees in complexes of closely related species.
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Affiliation(s)
- Peter H Weston
- The Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia
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9
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Kovach RP, Gharrett AJ, Tallmon DA. Temporal patterns of genetic variation in a salmon population undergoing rapid change in migration timing. Evol Appl 2013; 6:795-807. [PMID: 29387166 PMCID: PMC5779130 DOI: 10.1111/eva.12066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 03/04/2013] [Indexed: 01/17/2023] Open
Abstract
Though genetic diversity is necessary for population persistence in rapidly changing environments, little is known about how climate-warming influences patterns of intra-population genetic variation. For a pink salmon population experiencing increasing temperatures, we used temporal genetic data (microsatellite = 1993, 2001, 2009; allozyme = 1979, 1981, 1983) to quantify the genetic effective population size (Ne ) and genetic divergence due to differences in migration timing and to estimate whether these quantities have changed over time. We predicted that temporal trends toward earlier migration timing and a corresponding loss of phenotypic variation would decrease genetic divergence based on migration timing and Ne . We observed significant genetic divergence based on migration timing and genetic heterogeneity between early- and late-migrating fish. There was also some evidence for divergent selection between early- and late-migrating fish at circadian rhythm genes, but results varied over time. Estimates of Ne from multiple methods were large (>1200) and Ne /Nc generally exceeded 0.2. Despite shifts in migration timing and loss of phenotypic variation, there was no evidence for changes in within-population genetic divergence or Ne over the course of this study. These results suggest that in instances of population stability, genetic diversity may be resistant to climate-induced changes in migration timing.
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Affiliation(s)
- Ryan P Kovach
- Biology and Wildlife Department Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK USA
| | - Anthony J Gharrett
- School of Fisheries and Oceanic Sciences University of Alaska Fairbanks Juneau AK USA
| | - David A Tallmon
- Biology and Wildlife Department Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK USA
- School of Fisheries and Oceanic Sciences University of Alaska Fairbanks Juneau AK USA
- Biology and Marine Biology Program University of Alaska Southeast Juneau AK USA
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10
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Milner ML, Rossetto M, Crisp MD, Weston PH. The impact of multiple biogeographic barriers and hybridization on species-level differentiation. AMERICAN JOURNAL OF BOTANY 2012; 99:2045-2057. [PMID: 23221499 DOI: 10.3732/ajb.1200327] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY The glacial cycles of the Quaternary did not impact Australia in the same way as Europe and North America. Here we investigate the history of population isolation, species differentiation, and hybridization in the southeastern Australian landscape, using five species of Lomatia (Proteaceae). We use a chloroplast DNA phylogeography to assess chloroplast haplotype (chlorotype) sharing among these species and whether species with shared distributions have been affected by shared biogeographic barriers. • METHODS We used six chloroplast DNA simple sequence repeats (cpSSR) across five species of Lomatia, sampled across their entire distributional range in southeastern Australia. Resulting size data were combined, presented as a network, and visualized on a map. Biogeographical barriers were tested using AMOVA. To explore hypotheses of chlorotype origin, we converted the network into a cladogram and reconciled with all possible species trees using parsimony-based tree mapping. • KEY RESULTS Some chlorotypes were shared across multiple species of Lomatia in the study, including between morphologically differentiated species. Chlorotypes were either widespread in distribution or geographically restricted to specific regions. Biogeographical structure was identified across the range of Lomatia. The most parsimonious reconciled tree incorporated horizontal transfer of chlorotypes. • CONCLUSIONS Lomatia shows evidence of both incomplete lineage sorting and extensive hybridization between co-occurring species. Although the species in the study appear to have responded to a number of biogeographic barriers to varying degrees, our findings identified the Hunter River Valley as the most important long-term biogeographic barrier for the genus in southeastern Australia.
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Affiliation(s)
- Melita L Milner
- Evolution, Ecology and Genetics, School of Biology, The Australian National University, Building 116 Daley Road, Canberra, ACT 0200, Australia.
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