101
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Discovery and validation of species–specific diagnostic SNP markers for the endangered San Diego fairy shrimp (Branchinecta sandiegonensis) and the versatile fairy shrimp (Branchinecta lindahli). CONSERV GENET RESOUR 2017. [DOI: 10.1007/s12686-017-0912-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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102
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Peters KJ, Myers SA, Dudaniec RY, O'Connor JA, Kleindorfer S. Females drive asymmetrical introgression from rare to common species in Darwin's tree finches. J Evol Biol 2017; 30:1940-1952. [PMID: 28833876 DOI: 10.1111/jeb.13167] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 08/15/2017] [Indexed: 01/06/2023]
Abstract
The consequences of hybridization for biodiversity depend on the specific ecological and evolutionary context in which it occurs. Understanding patterns of gene flow among hybridizing species is crucial for determining the evolutionary trajectories of species assemblages. The recently discovered hybridization between two species of Darwin's tree finches (Camarhynchus parvulus and C. pauper) on Floreana Island, Galápagos, presents an exciting opportunity to investigate the mechanisms causing hybridization and its potential evolutionary consequences under conditions of recent habitat disturbance and the introduction of invasive pathogens. In this study, we combine morphological and genetic analysis with pairing observations to explore the extent, direction and drivers of hybridization and to test whether hybridization patterns are a result of asymmetrical pairing preference driven by females of the rarer species (C. pauper). We found asymmetrical introgression from the critically endangered, larger-bodied C. pauper to the common, smaller-bodied C. parvulus, which was associated with a lack of selection against heterospecific males by C. pauper females. Examination of pairing data showed that C. parvulus females paired assortatively, whereas C. pauper females showed no such pattern. This study shows how sex-specific drivers can determine the direction of gene flow in hybridizing species. Furthermore, our results suggest the existence of a hybrid swarm comprised of C. parvulus and hybrid birds. We discuss the influence of interspecific abundance differences and susceptibility to the invasive parasite Philornis downsi on the observed hybridization and recommend that the conservation of this iconic species group should be managed jointly rather than species-specific.
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Affiliation(s)
- K J Peters
- School of Biological Sciences, Flinders University, Adelaide, SA, Australia
| | - S A Myers
- Southern Seas Ecology Laboratory, School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - R Y Dudaniec
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - J A O'Connor
- Department of Environment, Water and Natural Resources, Adelaide, SA, Australia
| | - S Kleindorfer
- School of Biological Sciences, Flinders University, Adelaide, SA, Australia
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103
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van Boheemen LA, Lombaert E, Nurkowski KA, Gauffre B, Rieseberg LH, Hodgins KA. Multiple introductions, admixture and bridgehead invasion characterize the introduction history of Ambrosia artemisiifolia
in Europe and Australia. Mol Ecol 2017; 26:5421-5434. [DOI: 10.1111/mec.14293] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 08/05/2017] [Indexed: 01/16/2023]
Affiliation(s)
| | - Eric Lombaert
- UMR 1355 ISA; INRA; Sophia-Antipolis France
- UMR ISA; Université de Nice Sophia Antipolis; Sophia-Antipolis France
- UMR 7254 ISA; CNRS; Sophia-Antipolis France
| | | | - Bertrand Gauffre
- School of Biological Sciences; Monash University; Clayton VIC Australia
- UMR 7372; Centre d'Etudes Biologiques de Chizé; CNRS - Université de La Rochelle; Villiers-en-Bois France
- USC1339; Centre d'Etudes Biologiques de Chizé; INRA; Villiers-en-Bois France
| | - Loren H. Rieseberg
- Department of Botany; University of British Columbia; Vancouver BC Canada
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104
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Wango TL, Musiega D, Mundia CN, Altmann J, Alberts SC, Tung J. Climate and Land Cover Analysis Suggest No Strong Ecological Barriers to Gene Flow in a Natural Baboon Hybrid Zone. INT J PRIMATOL 2017. [DOI: 10.1007/s10764-017-9989-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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105
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Kerbs B, Ressler J, Kelly JK, Mort ME, Santos-Guerra A, Gibson MJS, Caujapé-Castells J, Crawford DJ. The potential role of hybridization in diversification and speciation in an insular plant lineage: insights from synthetic interspecific hybrids. AOB PLANTS 2017; 9:plx043. [PMID: 29225761 PMCID: PMC5714139 DOI: 10.1093/aobpla/plx043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 08/25/2017] [Indexed: 05/17/2023]
Abstract
Hybridization is recognized as an important process in plant evolution, and this may be particularly true for island plants where several biotic and abiotic factors facilitate interspecific hybridization. Although rarely done, experimental studies could provide insights into the potential of natural hybridization to generate diversity when species come into contact in the dynamic island setting. The potential of hybridization to generate morphological variation was analysed within and among 12 families (inbred lines) of an F4 hybrid generation between two species of Tolpis endemic to the Canary Islands. Combinations of characters not seen in the parents were present in hybrids. Several floral and vegetative characters were transgressive relative to their parents. Morphometric studies of floral, vegetative and fruit characters revealed that several F4 families were phenotypically distinct from other families, and from their parents. The study demonstrates that morphologically distinct pollen-fertile lines, potentially worthy of taxonomic recognition if occurring in nature, can be generated in four generations. The ability of the hybrid lines to set self-seed would reduce gene flow among the lines, and among the hybrids and their parental species. Selfing would also facilitate the fixation of characters within each of the lines. Overall, the results show the considerable potential of hybridization for generating diversity and distinct phenotypes in island lineages.
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Affiliation(s)
- Benjamin Kerbs
- Department of Biological Sciences, Emporia State University, Emporia, KS 66801, USA
| | - Jacob Ressler
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - John K Kelly
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045-7534, USA
| | - Mark E Mort
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045-7534, USA
| | - Arnoldo Santos-Guerra
- Calle Guaidil 16, Urbanización Tamarco, 38280 Tegueste, Tenerife, Canary Islands, Spain
| | | | - Juli Caujapé-Castells
- Jardín Botánico 13 Canario “Viera y Clavijo”-Unidad Asociada al CSIC (Cabildo de Gran Canaria), Camino del palmeral 14 15 (Tafira Alta), 35017 Las Palmas de Gran Canaria, Spain
| | - Daniel J Crawford
- Department of Ecology & Evolutionary Biology, and the Biodiversity Institute, University of Kansas, Lawrence, KS 66045-7534, USA
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106
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Dormontt EE, Prentis PJ, Gardner MG, Lowe AJ. Occasional hybridization between a native and invasive Senecio species in Australia is unlikely to contribute to invasive success. PeerJ 2017; 5:e3630. [PMID: 28828245 PMCID: PMC5562138 DOI: 10.7717/peerj.3630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 07/11/2017] [Indexed: 11/29/2022] Open
Abstract
Background Hybridization between native and invasive species can facilitate introgression of native genes that increase invasive potential by providing exotic species with pre-adapted genes suitable for new environments. In this study we assessed the outcome of hybridization between native Senecio pinnatifolius var. pinnatifolius A.Rich. (dune ecotype) and invasive Senecio madagascariensis Poir. to investigate the potential for introgression of adaptive genes to have facilitated S. madagascariensis spread in Australia. Methods We used amplified fragment length polymorphisms (141 loci) and nuclear microsatellites (2 loci) to genotype a total of 118 adults and 223 seeds from S. pinnatifolius var.pinnatifolius and S. madagascariensis at one allopatric and two shared sites. We used model based clustering and assignment methods to establish whether hybrid seed set and mature hybrids occur in the field. Results We detected no adult hybrids in any population. Low incidence of hybrid seed set was found at Lennox Head where the contact zone overlapped for 20 m (6% and 22% of total seeds sampled for S. pinnatifolius var. pinnatifolius and S. madagascariensis respectively). One hybrid seed was detected at Ballina where a gap of approximately 150 m was present between species (2% of total seeds sampled for S. madagascariensis). Conclusions We found no evidence of adult hybrid plants at two shared sites. Hybrid seed set from both species was identified at low levels. Based on these findings we conclude that introgression of adaptive genes from S. pinnatifolius var. pinnatifolius is unlikely to have facilitated S. madagascariensis invasions in Australia. Revisitation of one site after two years could find no remaining S. pinnatifolius var. pinnatifolius, suggesting that contact zones between these species are dynamic and that S. pinnatifolius var. pinnatifolius may be at risk of displacement by S. madagascariensis in coastal areas.
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Affiliation(s)
- Eleanor E Dormontt
- The Environment Institute, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Peter J Prentis
- Institute for Future Environments, School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Michael G Gardner
- School of Biological Sciences, Flinders University of South Australia, Adelaide, South Australia, Australia
| | - Andrew J Lowe
- The Environment Institute, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
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107
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Abstract
Many of the most important evolutionary variations that generated phenotypic adaptations and originated novel taxa resulted from complex cellular activities affecting genome content and expression. These activities included (i) the symbiogenetic cell merger that produced the mitochondrion-bearing ancestor of all extant eukaryotes, (ii) symbiogenetic cell mergers that produced chloroplast-bearing ancestors of photosynthetic eukaryotes, and (iii) interspecific hybridizations and genome doublings that generated new species and adaptive radiations of higher plants and animals. Adaptive variations also involved horizontal DNA transfers and natural genetic engineering by mobile DNA elements to rewire regulatory networks, such as those essential to viviparous reproduction in mammals. In the most highly evolved multicellular organisms, biological complexity scales with 'non-coding' DNA content rather than with protein-coding capacity in the genome. Coincidentally, 'non-coding' RNAs rich in repetitive mobile DNA sequences function as key regulators of complex adaptive phenotypes, such as stem cell pluripotency. The intersections of cell fusion activities, horizontal DNA transfers and natural genetic engineering of Read-Write genomes provide a rich molecular and biological foundation for understanding how ecological disruptions can stimulate productive, often abrupt, evolutionary transformations.
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Affiliation(s)
- James A Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago, GCISW123B, 979 E. 57th Street, Chicago, IL 60637, USA
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108
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109
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Mixing It Up: The Role of Hybridization in Forest Management and Conservation under Climate Change. FORESTS 2017. [DOI: 10.3390/f8070237] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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110
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Potts BM, Reid JB. HYBRIDIZATION AS A DISPERSAL MECHANISM. Evolution 2017; 42:1245-1255. [DOI: 10.1111/j.1558-5646.1988.tb04184.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/1987] [Accepted: 02/08/1988] [Indexed: 11/30/2022]
Affiliation(s)
- Bradley M. Potts
- Botany Department; University of Tasmania; Hobart Tasmania 7001 AUSTRALIA
| | - James B. Reid
- Botany Department; University of Tasmania; Hobart Tasmania 7001 AUSTRALIA
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111
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Vargas OM, Ortiz EM, Simpson BB. Conflicting phylogenomic signals reveal a pattern of reticulate evolution in a recent high-Andean diversification (Asteraceae: Astereae: Diplostephium). THE NEW PHYTOLOGIST 2017; 214:1736-1750. [PMID: 28333396 DOI: 10.1111/nph.14530] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 02/19/2017] [Indexed: 05/21/2023]
Abstract
High-throughput sequencing is helping biologists to overcome the difficulties of inferring the phylogenies of recently diverged taxa. The present study analyzes the phylogenetic signal of genomic regions with different inheritance patterns using genome skimming and ddRAD-seq in a species-rich Andean genus (Diplostephium) and its allies. We analyzed the complete nuclear ribosomal cistron, the complete chloroplast genome, a partial mitochondrial genome, and a nuclear-ddRAD matrix separately with phylogenetic methods. We applied several approaches to understand the causes of incongruence among datasets, including simulations and the detection of introgression using the D-statistic (ABBA-BABA test). We found significant incongruence among the nuclear, chloroplast, and mitochondrial phylogenies. The strong signal of hybridization found by simulations and the D-statistic among genera and inside the main clades of Diplostephium indicate reticulate evolution as a main cause of phylogenetic incongruence. Our results add evidence for a major role of reticulate evolution in events of rapid diversification. Hybridization and introgression confound chloroplast and mitochondrial phylogenies in relation to the species tree as a result of the uniparental inheritance of these genomic regions. Practical implications regarding the prevalence of hybridization are discussed in relation to the phylogenetic method.
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Affiliation(s)
- Oscar M Vargas
- Integrative Biology and Plant Resources Center, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University Ave, Ann Arbor, MI, 48109, USA
| | - Edgardo M Ortiz
- Integrative Biology and Plant Resources Center, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Beryl B Simpson
- Integrative Biology and Plant Resources Center, The University of Texas at Austin, Austin, TX, 78712, USA
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112
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Burke JM, Carney SE, Arnold ML. HYBRID FITNESS IN THE LOUISIANA IRISES: ANALYSIS OF PARENTAL AND F
1
PERFORMANCE. Evolution 2017; 52:37-43. [DOI: 10.1111/j.1558-5646.1998.tb05136.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/1997] [Accepted: 09/12/1997] [Indexed: 11/30/2022]
Affiliation(s)
- John M. Burke
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
| | - Shanna E. Carney
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
| | - Michael L. Arnold
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
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113
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Parris MJ. HYBRIDIZATION IN LEOPARD FROGS (
RANA PIPIENS
COMPLEX): LARVAL FITNESS COMPONENTS IN SINGLE‐GENOTYPE POPULATIONS AND MIXTURES. Evolution 2017; 53:1872-1883. [DOI: 10.1111/j.1558-5646.1999.tb04569.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/1998] [Accepted: 05/21/1999] [Indexed: 11/26/2022]
Affiliation(s)
- Matthew J. Parris
- Division of Biological Sciences, 105 Tucker Hall University of Missouri Columbia Missouri 65211‐7400
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114
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Zohary D, Feldman M. HYBRIDIZATION BETWEEN AMPHIDIPLOIDS AND THE EVOLUTION OF POLYPLOIDS IN THE WHEAT(AEGILOPS-TRITICUM)GROUP. Evolution 2017. [DOI: 10.1111/j.1558-5646.1962.tb03197.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Daniel Zohary
- Department of Botany; The Hebrew University; Jerusalem Israel
| | - Moshe Feldman
- Department of Botany; The Hebrew University; Jerusalem Israel
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115
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116
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Morishima H, Oka HI. THE PATTERN OF INTERSPECIFIC VARIATION IN THE GENUS ORYZA
: ITS QUANTITATIVE REPRESENTATION BY STATISTICAL METHODS. Evolution 2017. [DOI: 10.1111/j.1558-5646.1960.tb03074.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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117
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Chu YE, Oka HI. INTROGRESSION ACROSS ISOLATING BARRIERS IN WILD AND CULTIVATED ORYZA SPECIES. Evolution 2017; 24:344-355. [PMID: 28565062 DOI: 10.1111/j.1558-5646.1970.tb01766.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/1969] [Indexed: 11/30/2022]
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118
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Burke JM, Voss TJ, Arnold ML. GENETIC INTERACTIONS AND NATURAL SELECTION IN LOUISIANA IRIS HYBRIDS. Evolution 2017; 52:1304-1310. [PMID: 28565382 DOI: 10.1111/j.1558-5646.1998.tb02012.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/1998] [Accepted: 06/08/1998] [Indexed: 10/19/2022]
Affiliation(s)
- John M. Burke
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
| | - Tiffany J. Voss
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
| | - Michael L. Arnold
- Department of Genetics University of Georgia Athens Georgia 30602‐7223
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119
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Cain ML, Andreasen V, Howard DJ. REINFORCING SELECTION IS EFFECTIVE UNDER A RELATIVELY BROAD SET OF CONDITIONS IN A MOSAIC HYBRID ZONE. Evolution 2017; 53:1343-1353. [DOI: 10.1111/j.1558-5646.1999.tb05399.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/1998] [Accepted: 04/26/1999] [Indexed: 11/29/2022]
Affiliation(s)
- Michael L. Cain
- Department of Biology New Mexico State University Las Cruces New Mexico 88003
| | - Viggo Andreasen
- Department of Mathematics and Physics Roskilde University DK‐4000 Roskilde Denmark
| | - Daniel J. Howard
- Department of Biology New Mexico State University Las Cruces New Mexico 88003
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120
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121
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Smith HH, Daly K. DISCRETE POPULATIONS DERIVED BY INTERSPECIFIC HYBRIDIZATION AND SELECTION INNICOTIANA. Evolution 2017. [DOI: 10.1111/j.1558-5646.1959.tb03037.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Kevin Daly
- Department of Plant Breeding; Cornell University; Ithaca N. Y
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122
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Arnold ML, Bennett BD, Zimmer EA. NATURAL HYBRIDIZATION BETWEEN IRIS FULVA
AND IRIS HEXAGONA
: PATTERN OF RIBOSOMAL DNA VARIATION. Evolution 2017; 44:1512-1521. [PMID: 28564316 DOI: 10.1111/j.1558-5646.1990.tb03842.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/1989] [Accepted: 12/22/1989] [Indexed: 11/28/2022]
Affiliation(s)
- Michael L. Arnold
- Department of Biochemistry; Louisiana State University; Baton Rouge LA 70803 USA
| | - Bobby D. Bennett
- Department of Botany; Louisiana State University; Baton Rouge LA 70803 USA
| | - Elizabeth A. Zimmer
- Department of Biochemistry; Louisiana State University; Baton Rouge LA 70803 USA
- Department of Botany; Louisiana State University; Baton Rouge LA 70803 USA
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123
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dePamphilis CW, Wyatt R. ELECTROPHORETIC CONFIRMATION OF INTERSPECIFIC HYBRIDIZATION IN
AESCULUS
(HIPPOCASTANACEAE) AND THE GENETIC STRUCTURE OF A BROAD HYBRID ZONE. Evolution 2017; 44:1295-1317. [DOI: 10.1111/j.1558-5646.1990.tb05233.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/1988] [Accepted: 12/20/1989] [Indexed: 11/28/2022]
Affiliation(s)
| | - Robert Wyatt
- Department of Botany University of Georgia Athens GA 30602 USA
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124
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Nelson RM, Wallberg A, Simões ZLP, Lawson DJ, Webster MT. Genomewide analysis of admixture and adaptation in the Africanized honeybee. Mol Ecol 2017; 26:3603-3617. [PMID: 28378497 DOI: 10.1111/mec.14122] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 03/08/2016] [Accepted: 03/20/2017] [Indexed: 02/03/2023]
Abstract
Genetic exchange by hybridization or admixture can make an important contribution to evolution, and introgression of favourable alleles can facilitate adaptation to new environments. A small number of honeybees (Apis mellifera) with African ancestry were introduced to Brazil ~60 years ago, which dispersed and hybridized with existing managed populations of European origin, quickly spreading across much of the Americas in an example of a massive biological invasion. Here, we analyse whole-genome sequences of 32 Africanized honeybees sampled from throughout Brazil to study the effect of this process on genome diversity. By comparison with ancestral populations from Europe and Africa, we infer that these samples have 84% African ancestry, with the remainder from western European populations. However, this proportion varies across the genome and we identify signals of positive selection in regions with high European ancestry proportions. These observations are largely driven by one large gene-rich 1.4-Mbp segment on chromosome 11 where European haplotypes are present at a significantly elevated frequency and likely confer an adaptive advantage in the Africanized honeybee population. This region has previously been implicated in reproductive traits and foraging behaviour in worker bees. Finally, by analysing the distribution of ancestry tract lengths in the context of the known time of the admixture event, we are able to infer an average generation time of 2.0 years. Our analysis highlights the processes by which populations of mixed genetic ancestry form and adapt to new environments.
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Affiliation(s)
- Ronald M Nelson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Andreas Wallberg
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Zilá Luz Paulino Simões
- Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil.,Department of Genetics, FMRP, University of São Paulo, Ribeirão Preto, Brazil
| | - Daniel J Lawson
- Department of Mathematics, University of Bristol, Bristol, UK
| | - Matthew T Webster
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
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125
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Meier JI, Marques DA, Mwaiko S, Wagner CE, Excoffier L, Seehausen O. Ancient hybridization fuels rapid cichlid fish adaptive radiations. Nat Commun 2017; 8:14363. [PMID: 28186104 PMCID: PMC5309898 DOI: 10.1038/ncomms14363] [Citation(s) in RCA: 357] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 12/20/2016] [Indexed: 01/01/2023] Open
Abstract
Understanding why some evolutionary lineages generate exceptionally high species diversity is an important goal in evolutionary biology. Haplochromine cichlid fishes of Africa's Lake Victoria region encompass >700 diverse species that all evolved in the last 150,000 years. How this 'Lake Victoria Region Superflock' could evolve on such rapid timescales is an enduring question. Here, we demonstrate that hybridization between two divergent lineages facilitated this process by providing genetic variation that subsequently became recombined and sorted into many new species. Notably, the hybridization event generated exceptional allelic variation at an opsin gene known to be involved in adaptation and speciation. More generally, differentiation between new species is accentuated around variants that were fixed differences between the parental lineages, and that now appear in many new combinations in the radiation species. We conclude that hybridization between divergent lineages, when coincident with ecological opportunity, may facilitate rapid and extensive adaptive radiation.
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Affiliation(s)
- Joana I. Meier
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre for Ecology, Evolution & Biogeochemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Computational and Molecular Population Genetics Lab, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
| | - David A. Marques
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre for Ecology, Evolution & Biogeochemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Computational and Molecular Population Genetics Lab, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
| | - Salome Mwaiko
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre for Ecology, Evolution & Biogeochemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
| | - Catherine E. Wagner
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre for Ecology, Evolution & Biogeochemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Biodiversity Institute & Department of Botany, University of Wyoming, Laramie Wyoming 82071, USA
| | - Laurent Excoffier
- Computational and Molecular Population Genetics Lab, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Ole Seehausen
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Department of Fish Ecology and Evolution, Centre for Ecology, Evolution & Biogeochemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
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126
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Ortego J, Gugger PF, Sork VL. Impacts of human-induced environmental disturbances on hybridization between two ecologically differentiated Californian oak species. THE NEW PHYTOLOGIST 2017; 213:942-955. [PMID: 27621132 DOI: 10.1111/nph.14182] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/04/2016] [Indexed: 05/15/2023]
Abstract
Natural hybridization, which can be involved in local adaptation and in speciation processes, has been linked to different sources of anthropogenic disturbance. Here, we use genotypic data to study range-wide patterns of genetic admixture between the serpentine-soil specialist leather oak (Quercus durata) and the widespread Californian scrub oak (Quercus berberidifolia). First, we estimated hybridization rates and the direction of gene flow. Second, we tested the hypothesis that genetic admixture increases with different sources of environmental disturbance, namely anthropogenic destruction of natural habitats and wildfire frequency estimated from long-term records of fire occurrence. Our analyses indicate considerable rates of hybridization (> 25%), asymmetric gene flow from Q. durata into Q. berberidifolia, and a higher occurrence of hybrids in areas where both species live in close parapatry. In accordance with the environmental disturbance hypothesis, we found that genetic admixture increases with wildfire frequency, but we did not find a significant effect of other sources of human-induced habitat alteration (urbanization, land clearing for agriculture) or a suite of ecological factors (climate, elevation, soil type). Our findings highlight that wildfires constitute an important source of environmental disturbance, promoting hybridization between two ecologically well-differentiated native species.
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Affiliation(s)
- Joaquín Ortego
- Department of Integrative Ecology, Estación Biológica de Doñana, EBD-CSIC, Avda. Américo Vespucio s/n, E-41092, Seville, Spain
| | - Paul F Gugger
- Appalachian Laboratory, University of Maryland Center for Environmental Science, 301 Braddock Road, Frostburg, MD, 21532, USA
| | - Victoria L Sork
- Department of Ecology and Evolutionary Biology, University of California, Box 957239, Los Angeles, CA, 90095, USA
- Institute of the Environment and Sustainability, University of California, Box 951496, Los Angeles, CA, 90095-1496, USA
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127
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Stankowski S, Streisfeld MA. Introgressive hybridization facilitates adaptive divergence in a recent radiation of monkeyflowers. Proc Biol Sci 2016; 282:rspb.2015.1666. [PMID: 26311673 DOI: 10.1098/rspb.2015.1666] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A primary goal in evolutionary biology is to identify the historical events that have facilitated the origin and spread of adaptations. When these adaptations also lead to reproductive isolation, we can learn about the evolutionary mechanisms contributing to speciation. We reveal the complex history of the gene MaMyb2 in shaping flower colour divergence within a recent radiation of monkey flowers.In the Mimulus aurantiacus species complex, red-flowered M. a. ssp. puniceus and yellow-flowered M. a. ssp. australis are partially isolated because of differences in pollinator preferences. Phylogenetic analyses based on genome-wide variation across the complex suggest two origins of red flowers from a yellow-flowered ancestor: one in M. a. ssp. puniceus and one in M. a. ssp.flemingii. However, in both cases, red flowers are caused by cis-regulatory mutations in the gene MaMyb2. Although this could be due to distinct mutations in each lineage, we show that the red allele in M. a. ssp. puniceus did not evolve de novo or exist as standing variation in its yellow-flowered ancestor. Rather, our results suggest that a single red MaMyb2 allele evolved during the radiation of M. aurantiacus that was subsequently transferred to the yellow-flowered ancestor of M. a. ssp. puniceus via introgressive hybridization. Because gene flow is still possible among taxa, we conclude that introgressive hybridization can be a potent driver of adaptation at the early stages of divergence that can contribute to the origins of biodiversity.
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128
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Wall JD, Schlebusch SA, Alberts SC, Cox LA, Snyder-Mackler N, Nevonen K, Carbone L, Tung J. Genomewide ancestry and divergence patterns from low-coverage sequencing data reveal a complex history of admixture in wild baboons. Mol Ecol 2016; 25:3469-83. [PMID: 27145036 PMCID: PMC5306399 DOI: 10.1111/mec.13684] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 11/26/2022]
Abstract
Naturally occurring admixture has now been documented in every major primate lineage, suggesting its key role in primate evolutionary history. Active primate hybrid zones can provide valuable insight into this process. Here, we investigate the history of admixture in one of the best-studied natural primate hybrid zones, between yellow baboons (Papio cynocephalus) and anubis baboons (Papio anubis) in the Amboseli ecosystem of Kenya. We generated a new genome assembly for yellow baboon and low-coverage genomewide resequencing data from yellow baboons, anubis baboons and known hybrids (n = 44). Using a novel composite likelihood method for estimating local ancestry from low-coverage data, we found high levels of genetic diversity and genetic differentiation between the parent taxa, and excellent agreement between genome-scale ancestry estimates and a priori pedigree, life history and morphology-based estimates (r(2) = 0.899). However, even putatively unadmixed Amboseli yellow individuals carried a substantial proportion of anubis ancestry, presumably due to historical admixture. Further, the distribution of shared vs. fixed differences between a putatively unadmixed Amboseli yellow baboon and an unadmixed anubis baboon, both sequenced at high coverage, is inconsistent with simple isolation-migration or equilibrium migration models. Our findings suggest a complex process of intermittent contact that has occurred multiple times in baboon evolutionary history, despite no obvious fitness costs to hybrids or major geographic or behavioural barriers. In combination with the extensive phenotypic data available for baboon hybrids, our results provide valuable context for understanding the history of admixture in primates, including in our own lineage.
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Affiliation(s)
- Jeffrey D Wall
- Institute for Human Genetics, University of California-San Francisco, Box 0794, San Francisco, CA 94143, USA
| | - Stephen A Schlebusch
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7700, Cape Town, South Africa
| | - Susan C Alberts
- Department of Evolutionary Anthropology, Duke University, Box 90383, Durham, NC 27708, USA
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
- Institute of Primate Research, National Museums of Kenya, P. O. Box 24481, Karen 00502, Nairobi, Kenya
| | - Laura A Cox
- Department of Genetics and Southwest National Primate Research Center, Texas Biomedical Research Institute, Box 760549, San Antonio, TX 78245, USA
| | - Noah Snyder-Mackler
- Department of Evolutionary Anthropology, Duke University, Box 90383, Durham, NC 27708, USA
| | - Kimberly Nevonen
- Division of Neuroscience, Primate Genetics Section, Oregon National Primate Research Center, 505 NW 185 Ave, Beaverton, OR 97006, USA
- Behavioral Neuroscience Department, Oregon Health Sciences University, 3181 SW, Sam Jackson Park Road, Portland, OR 97239, USA
| | - Lucia Carbone
- Division of Neuroscience, Primate Genetics Section, Oregon National Primate Research Center, 505 NW 185 Ave, Beaverton, OR 97006, USA
- Behavioral Neuroscience Department, Oregon Health Sciences University, 3181 SW, Sam Jackson Park Road, Portland, OR 97239, USA
| | - Jenny Tung
- Department of Evolutionary Anthropology, Duke University, Box 90383, Durham, NC 27708, USA
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
- Institute of Primate Research, National Museums of Kenya, P. O. Box 24481, Karen 00502, Nairobi, Kenya
- Duke University Population Research Institute, Duke University, Box 90420, Durham, NC 27708, USA
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129
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Kovach RP, Luikart G, Lowe WH, Boyer MC, Muhlfeld CC. Risk and efficacy of human-enabled interspecific hybridization for climate-change adaptation: response to Hamilton and Miller (2016). CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2016; 30:428-430. [PMID: 26918487 DOI: 10.1111/cobi.12678] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Ryan P Kovach
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park West Glacier, MT, 59936, U.S.A
| | - Gordon Luikart
- Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, U.S.A
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, U.S.A
| | | | - Clint C Muhlfeld
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park West Glacier, MT, 59936, U.S.A
- Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, U.S.A
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130
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Todesco M, Pascual MA, Owens GL, Ostevik KL, Moyers BT, Hübner S, Heredia SM, Hahn MA, Caseys C, Bock DG, Rieseberg LH. Hybridization and extinction. Evol Appl 2016; 9:892-908. [PMID: 27468307 PMCID: PMC4947151 DOI: 10.1111/eva.12367] [Citation(s) in RCA: 339] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 01/28/2016] [Indexed: 01/29/2023] Open
Abstract
Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization‐induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization‐prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.
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Affiliation(s)
- Marco Todesco
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Mariana A Pascual
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Gregory L Owens
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Katherine L Ostevik
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Brook T Moyers
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada; Department of Bioagricultural Sciences and Pest Management Colorado State University Ft Collins CO USA
| | - Sariel Hübner
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Sylvia M Heredia
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Min A Hahn
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Celine Caseys
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Dan G Bock
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Loren H Rieseberg
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver BC Canada; Department of Biology Indiana University Bloomington IN USA
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131
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Bisi F, Wauters LA, Preatoni DG, Martinoli A. Interspecific competition mediated by climate change: which interaction between brown and mountain hare in the Alps? Mamm Biol 2015. [DOI: 10.1016/j.mambio.2015.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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132
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Wu Z, Ding Z, Yu D, Xu X. Influence of niche similarity on hybridization between Myriophyllum sibiricum and M. spicatum. J Evol Biol 2015; 28:1465-75. [PMID: 26059210 DOI: 10.1111/jeb.12667] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/15/2015] [Indexed: 11/28/2022]
Abstract
The impact of ecological factors on natural hybridization is of widespread interest. Here, we asked whether climate niche influences hybridization between the two closely related plant species Myriophyllum sibiricum and M. spicatum. Eight microsatellite loci and two chloroplast fragments were used to investigate the occurrence of hybridization between these two species in two co-occurring regions: north-east China (NEC) and the Qinghai-Tibetan Plateau (QTP). The climate niches of the species were quantified by principal component analysis with bioclimatic data, and niche comparisons were performed between the two species in each region. Reciprocal hybridization was observed, and M. sibiricum was favoured as the maternal species. Furthermore, hybrids were rare in NEC but common in the QTP. Accordingly, in NEC, the two species were climatically distinct, and hybrids only occurred in the narrow geographical or ecological transition zone, whereas in the QTP, obvious niche overlaps were found for the two species, and hybrids occurred in multiple contact zones. This association between hybridization pattern and climate niche similarity suggests that the level of hybridization was promoted by niche overlap. Compared with the parental species, similar climate niches were found for the hybrid populations in the QTP, indicating that other environmental factors rather than climate were important for hybrid persistence. Our findings highlight the significance of climate niche with respect to hybridization patterns in plants.
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Affiliation(s)
- Z Wu
- National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, China
| | - Z Ding
- National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, China
| | - D Yu
- National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, China
| | - X Xu
- National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, China
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133
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Kost MA, Alexander HM, Jason Emry D, Mercer KL. Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression. Evol Appl 2015; 8:510-24. [PMID: 26029263 PMCID: PMC4430773 DOI: 10.1111/eva.12261] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 03/18/2015] [Indexed: 12/01/2022] Open
Abstract
Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop-wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations.
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Affiliation(s)
- Matthew A Kost
- Department of Horticulture and Crop Science, The Ohio State UniversityWooster, OH, USA
| | - Helen M Alexander
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
| | - D Jason Emry
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
- Department of Biology, Washburn UniversityTopeka, KS, USA
| | - Kristin L Mercer
- Department of Horticulture and Crop Science, The Ohio State UniversityColumbus, OH, USA
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134
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Warschefsky E, Penmetsa RV, Cook DR, von Wettberg EJB. Back to the wilds: tapping evolutionary adaptations for resilient crops through systematic hybridization with crop wild relatives. AMERICAN JOURNAL OF BOTANY 2014; 101:1791-800. [PMID: 25326621 DOI: 10.3732/ajb.1400116] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The genetic diversity of our crop plants has been substantially reduced during the process of domestication and breeding. This reduction in diversity necessarily constrains our ability to expand a crop's range of cultivation into environments that are more extreme than those in which it was domesticated, including into "sustainable" agricultural systems with reduced inputs of pesticides, water, and fertilizers. Conversely, the wild progenitors of crop plants typically possess high levels of genetic diversity, which underlie an expanded (relative to domesticates) range of adaptive traits that may be of agricultural relevance, including resistance to pests and pathogens, tolerance to abiotic extremes, and reduced dependence on inputs. Despite their clear potential for crop improvement, wild relatives have rarely been used systematically for crop improvement, and in no cases, have full sets of wild diversity been introgressed into a crop. Instead, most breeding efforts have focused on specific traits and dealt with wild species in a limited and typically ad hoc manner. Although expedient, this approach misses the opportunity to test a large suite of traits and deploy the full potential of crop wild relatives in breeding for the looming challenges of the 21st century. Here we review examples of hybridization in several species, both intentionally produced and naturally occurring, to illustrate the gains that are possible. We start with naturally occurring hybrids, and then examine a range of examples of hybridization in agricultural settings.
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Affiliation(s)
- Emily Warschefsky
- Department of Biological Sciences, Florida International University 12200 SW 8th Street, Miami, Florida 33199 USA Kushlan Center for Tropical Science, Fairchild Tropical Botanic Garden 10901 Old Cutler Road, Coral Gables, Florida 33156 USA
| | - R Varma Penmetsa
- Department of Plant Pathology, University of California-Davis, One Shields Avenue, Davis, California 95616 USA
| | - Douglas R Cook
- Department of Plant Pathology, University of California-Davis, One Shields Avenue, Davis, California 95616 USA
| | - Eric J B von Wettberg
- Department of Biological Sciences, Florida International University 12200 SW 8th Street, Miami, Florida 33199 USA Kushlan Center for Tropical Science, Fairchild Tropical Botanic Garden 10901 Old Cutler Road, Coral Gables, Florida 33156 USA
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135
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Zhao W, Meng J, Wang B, Zhang L, Xu Y, Zeng QY, Li Y, Mao JF, Wang XR. Weak crossability barrier but strong juvenile selection supports ecological speciation of the hybrid pine Pinus densata on the Tibetan plateau. Evolution 2014; 68:3120-33. [PMID: 25065387 PMCID: PMC4278550 DOI: 10.1111/evo.12496] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 07/10/2014] [Indexed: 12/16/2022]
Abstract
Determining how a new hybrid lineage can achieve reproductive isolation is a key to understanding the process and mechanisms of homoploid hybrid speciation. Here, we evaluated the degree and nature of reproductive isolation between the ecologically successful hybrid species Pinus densata and its parental species P. tabuliformis and P. yunnanensis. We performed interspecific crosses among the three species to assess their crossability. We then conducted reciprocal transplantation experiments to evaluate their fitness differentiation, and to examine how natural populations representing different directions of introgression differ in adaptation. The crossing experiments revealed weak genetic barriers among the species. The transplantation trials showed manifest evidence of local adaptation as the three species all performed best in their native habitats. Pinus densata populations from the western edge of its distribution have evolved a strong local adaptation to the specific habitat in that range; populations representing different directions of introgressants with the two parental species all showed fitness disadvantages in this P. densata habitat. These observations illustrate that premating isolation through selection against immigrants from other habitat types or postzygotic isolation through selection against backcrosses between the three species is strong. Thus, ecological selection in combination with endogenous components and geographic isolation has likely played a significant role in the speciation of P. densata.
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Affiliation(s)
- Wei Zhao
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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136
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Hovick SM, Whitney KD. Hybridisation is associated with increased fecundity and size in invasive taxa: meta-analytic support for the hybridisation-invasion hypothesis. Ecol Lett 2014; 17:1464-77. [PMID: 25234578 PMCID: PMC4231983 DOI: 10.1111/ele.12355] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/11/2014] [Accepted: 08/14/2014] [Indexed: 02/04/2023]
Abstract
The hypothesis that interspecific hybridisation promotes invasiveness has received much recent
attention, but tests of the hypothesis can suffer from important limitations. Here, we provide the
first systematic review of studies experimentally testing the hybridisation-invasion (H-I)
hypothesis in plants, animals and fungi. We identified 72 hybrid systems for which hybridisation has
been putatively associated with invasiveness, weediness or range expansion. Within this group, 15
systems (comprising 34 studies) experimentally tested performance of hybrids vs. their parental
species and met our other criteria. Both phylogenetic and non-phylogenetic meta-analyses
demonstrated that wild hybrids were significantly more fecund and larger than their parental taxa,
but did not differ in survival. Resynthesised hybrids (which typically represent earlier generations
than do wild hybrids) did not consistently differ from parental species in fecundity, survival or
size. Using meta-regression, we found that fecundity increased (but survival decreased) with
generation in resynthesised hybrids, suggesting that natural selection can play an important role in
shaping hybrid performance – and thus invasiveness – over time. We conclude that the
available evidence supports the H-I hypothesis, with the caveat that our results are clearly driven
by tests in plants, which are more numerous than tests in animals and fungi.
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Affiliation(s)
- Stephen M Hovick
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
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137
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Ellstrand NC. Is gene flow the most important evolutionary force in plants? AMERICAN JOURNAL OF BOTANY 2014; 101:737-53. [PMID: 24752890 DOI: 10.3732/ajb.1400024] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 03/17/2014] [Indexed: 05/02/2023]
Abstract
Although theory has demonstrated rather low levels of gene flow are sufficient to counteract opposing mutation, drift, and selection, widespread recognition of the evolutionary importance of gene flow has come slowly. The perceived role of gene flow as an evolutionary force has vacillated over the last century. In the last few decades, new methods and analyses have demonstrated that plant gene flow rates vary tremendously-from nil to very high-depending on the species and specific populations involved, and sometimes over time for individual populations. In many cases, the measured gene flow rates are evolutionarily significant at distances of hundreds and sometimes thousands of meters, occurring at levels sufficient to counteract drift, spread advantageous alleles, or thwart moderate levels of opposing local selection. Gene flow in plants is likely to often act as a cohesive force, uniting individual plant species into real evolutionary units. Also, gene flow can evolve under natural selection, decreasing or increasing. The fact of frequent, but variable, plant gene flow has important consequences for applied issues in which the presence or absence of gene flow might influence the outcome of a policy, regulatory, or management decision. Examples include the unintended spread of engineered genes, the evolution of invasiveness, and conservation. New data-rich genomic techniques allow closer scrutiny of the role of gene flow in plant evolution. Most plant evolutionists now recognize the importance of gene flow, and it is receiving increased recognition from other areas of plant biology as well.
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Affiliation(s)
- Norman C Ellstrand
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521-0124 USA
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138
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Roe AD, MacQuarrie CJK, Gros-Louis MC, Simpson JD, Lamarche J, Beardmore T, Thompson SL, Tanguay P, Isabel N. Fitness dynamics within a poplar hybrid zone: I. Prezygotic and postzygotic barriers impacting a native poplar hybrid stand. Ecol Evol 2014; 4:1629-47. [PMID: 24967081 PMCID: PMC4063464 DOI: 10.1002/ece3.1029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/20/2013] [Accepted: 12/31/2013] [Indexed: 01/30/2023] Open
Abstract
Hybridization and introgression are pervasive evolutionary phenomena that provide insight into the selective forces that maintain species boundaries, permit gene flow, and control the direction of evolutionary change. Poplar trees (Populus L.) are well known for their ability to form viable hybrids and maintain their distinct species boundaries despite this interspecific gene flow. We sought to quantify the hybridization dynamics and postzygotic fitness within a hybrid stand of balsam poplar (Populus balsamifera L.), eastern cottonwood (P. deltoides Marsh.), and their natural hybrids to gain insight into the barriers maintaining this stable hybrid zone. We observed asymmetrical hybrid formation with P. deltoides acting as the seed parent, but with subsequent introgression biased toward P. balsamifera. Native hybrids expressed fitness traits intermediate to the parental species and were not universally unfit. That said, native hybrid seedlings were absent from the seedling population, which may indicate additional selective pressures controlling their recruitment. It is imperative that we understand the selective forces maintaining this native hybrid zone in order to quantify the impact of exotic poplar hybrids on this native system.
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Affiliation(s)
- Amanda D Roe
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
- Natural Resources Canada, Canadian Forestry Centre, Great Lakes Forestry CentreSault Ste. Marie, Ontario, Canada
| | - Chris J K MacQuarrie
- Natural Resources Canada, Canadian Forestry Centre, Great Lakes Forestry CentreSault Ste. Marie, Ontario, Canada
| | - Marie-Claude Gros-Louis
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - J Dale Simpson
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry CentreFredericton, New Brunswick, Canada
| | - Josyanne Lamarche
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - Tannis Beardmore
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry CentreFredericton, New Brunswick, Canada
| | - Stacey L Thompson
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
- Umeå University, Ecology and Environmental Sciences, Umeå Plant Science CentreUmeå, Sweden
| | - Philippe Tanguay
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
| | - Nathalie Isabel
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry CentreQuébec, Québec, Canada
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139
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Chunco AJ. Hybridization in a warmer world. Ecol Evol 2014; 4:2019-31. [PMID: 24963394 PMCID: PMC4063493 DOI: 10.1002/ece3.1052] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 03/01/2014] [Accepted: 03/11/2014] [Indexed: 01/09/2023] Open
Abstract
Climate change is profoundly affecting the evolutionary trajectory of individual species and ecological communities, in part through the creation of novel species assemblages. How climate change will influence competitive interactions has been an active area of research. Far less attention, however, has been given to altered reproductive interactions. Yet, reproductive interactions between formerly isolated species are inevitable as populations shift geographically and temporally as a result of climate change, potentially resulting in introgression, speciation, or even extinction. The susceptibility of hybridization rates to anthropogenic disturbance was first recognized in the 1930s. To date, work on anthropogenically mediated hybridization has focused primarily on either physical habitat disturbance or species invasion. Here, I review recent literature on hybridization to identify how ecological responses to climate change will increase the likelihood of hybridization via the dissolution of species barriers maintained by habitat, time, or behavior. Using this literature, I identify several cases where novel hybrid zones have recently formed, likely as a result of changing climate. Future research should focus on identifying areas and taxonomic groups where reproductive species interactions are most likely to be influenced by climate change. Furthermore, a better understanding of the evolutionary consequences of climate-mediated secondary contact is urgently needed. Paradoxically, hybridization is both a major conservation concern and an important source of novel genetic and phenotypic variation. Hybridization may therefore both contribute to increasing rates of extinction and stimulate the creation of novel phenotypes that will speed adaptation to novel climates. Predicting which result will occur following secondary contact will be an important contribution to conservation for many species.
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Affiliation(s)
- Amanda J Chunco
- Department of Environmental Studies, Elon University CB 2015, Elon, North Carolina 27244
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140
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Selz OM, Thommen R, Maan ME, Seehausen O. Behavioural isolation may facilitate homoploid hybrid speciation in cichlid fish. J Evol Biol 2013; 27:275-89. [DOI: 10.1111/jeb.12287] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 09/06/2013] [Accepted: 10/27/2013] [Indexed: 01/29/2023]
Affiliation(s)
- O. M. Selz
- Department of Fish Ecology and Evolution; EAWAG Swiss Federal Institute of Aquatic Science and Technology; Center for Ecology, Evolution and Biogeochemistry; Kastanienbaum Switzerland
- Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | - R. Thommen
- Department of Fish Ecology and Evolution; EAWAG Swiss Federal Institute of Aquatic Science and Technology; Center for Ecology, Evolution and Biogeochemistry; Kastanienbaum Switzerland
- Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | - M. E. Maan
- Behavioural Biology Research Group; Center for Behaviour and Neurosciences; University of Groningen; Groningen The Netherlands
| | - O. Seehausen
- Department of Fish Ecology and Evolution; EAWAG Swiss Federal Institute of Aquatic Science and Technology; Center for Ecology, Evolution and Biogeochemistry; Kastanienbaum Switzerland
- Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
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141
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Selz OM, Lucek K, Young KA, Seehausen O. Relaxed trait covariance in interspecific cichlid hybrids predicts morphological diversity in adaptive radiations. J Evol Biol 2013; 27:11-24. [DOI: 10.1111/jeb.12283] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/27/2013] [Indexed: 01/29/2023]
Affiliation(s)
- O. M. Selz
- Department of Fish Ecology and Evolution; EAWAG Swiss Federal Institute of Aquatic Science and Technology; Center for Ecology, Evolution and Biogeochemistry; Kastanienbaum Switzerland
- Division of Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | - K. Lucek
- Department of Fish Ecology and Evolution; EAWAG Swiss Federal Institute of Aquatic Science and Technology; Center for Ecology, Evolution and Biogeochemistry; Kastanienbaum Switzerland
- Division of Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | | | - O. Seehausen
- Division of Aquatic Ecology and Evolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
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142
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Devillard S, Jombart T, Léger F, Pontier D, Say L, Ruette S. How reliable are morphological and anatomical characters to distinguish European wildcats, domestic cats and their hybrids in France? J ZOOL SYST EVOL RES 2013. [DOI: 10.1111/jzs.12049] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sébastien Devillard
- Université de Lyon, F-69000, Lyon; Université Lyon 1; CNRS, UMR5558; Laboratoire de Biométrie et Biologie Evolutive; F-69622; Villeurbanne France
| | - Thibaut Jombart
- MRC Centre for Outbreak Analysis and Modelling; Department of Infectious Disease Epidemiology; Imperial College - School of Public Health; London UK
| | - François Léger
- Office National de la Chasse et de la Faune Sauvage; Montfort Birieux France
| | - Dominique Pontier
- Université de Lyon, F-69000, Lyon; Université Lyon 1; CNRS, UMR5558; Laboratoire de Biométrie et Biologie Evolutive; F-69622; Villeurbanne France
| | - Ludovic Say
- Université de Lyon, F-69000, Lyon; Université Lyon 1; CNRS, UMR5558; Laboratoire de Biométrie et Biologie Evolutive; F-69622; Villeurbanne France
| | - Sandrine Ruette
- Office National de la Chasse et de la Faune Sauvage; Montfort Birieux France
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143
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Baldassarre DT, Webster MS. Experimental evidence that extra-pair mating drives asymmetrical introgression of a sexual trait. Proc Biol Sci 2013; 280:20132175. [PMID: 24089341 DOI: 10.1098/rspb.2013.2175] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theory suggests that traits under positive selection may introgress asymmetrically across a hybrid zone, potentially driven by sexual selection. Two subspecies of the red-backed fairy-wren (Malurus melanocephalus) differ primarily in a sexual signal used in mate choice-red versus orange male back plumage colour-but phylogeographic analyses suggest asymmetrical introgression of red plumage into the genetic background of the orange subspecies. We hypothesized that this asymmetrical introgression may be facilitated by sexual selection if red males have a mating advantage over orange males. We tested this hypothesis with correlational data and a plumage manipulation experiment where we reddened the back plumage of a subset of orange males to mimic males of the red subspecies. There was no correlational evidence of a mating advantage to naturally redder males in this population. Experimentally reddened males sired a similar amount of within-pair young and lost paternity at the same rate as orange males, but they sired significantly more extra-pair young, leading to substantially higher total reproductive success. Thus, we conclude that sexual selection via extra-pair mating is a likely mechanism responsible for the asymmetrical introgression of plumage colour in this system, and is potentially driven by a sensory bias for the red plumage signal.
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Affiliation(s)
- Daniel T Baldassarre
- Department of Neurobiology and Behavior, Cornell University, , Ithaca, NY 14850, USA, Macaulay Library, Cornell Lab of Ornithology, , Ithaca, NY 14853, USA
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144
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Larue EA, Zuellig MP, Netherland MD, Heilman MA, Thum RA. Hybrid watermilfoil lineages are more invasive and less sensitive to a commonly used herbicide than their exotic parent (Eurasian watermilfoil). Evol Appl 2013; 6:462-71. [PMID: 23745138 PMCID: PMC3673474 DOI: 10.1111/eva.12027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 10/02/2012] [Indexed: 11/27/2022] Open
Abstract
Hybridization may stimulate the evolution of invasiveness in human-impacted habitats if unique
hybrid genotypes have higher fitness than parental genotypes. Human efforts to control invasive taxa
frequently involve the intentional alteration of habitats, but few studies have considered whether
hybridization can result in decreased sensitivity to control measures. Here, we investigate whether
interspecific hybrids between introduced Eurasian watermilfoil (Myriophyllum
spicatum) and native northern watermilfoil (M. sibiricum) are more
invasive than parental Eurasian watermilfoil, especially in regard to their relative responses to an
herbicide commonly applied for their control (2,4-dichlorophenoxyacetic acid; 2,4-D). In two
separate laboratory experiments, hybrids on average grew faster and were less sensitive to 2,4-D
compared with parental Eurasian watermilfoil. These two invasive traits appear to be common in
hybrid watermilfoils, as opposed to being restricted to a few unique lineages, because they were
found in a diversity of hybrid genotypes from several independent hybridization events. In addition,
we found that hybrids occurred more frequently than parental species in natural lakes previously
treated with 2,4-D. Our results provide compelling empirical evidence that hybridization is
associated with the evolution of increased invasiveness in watermilfoils, and have important
implications for their management.
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Affiliation(s)
- Elizabeth A Larue
- Annis Water Resources Institute, Grand Valley State University Muskegon, MI, USA ; Department of Biological Sciences, Purdue University West Lafayette, IN, USA
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145
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Bossu CM, Near TJ. Characterization of a contemporaneous hybrid zone between two darter species (Etheostoma bison and E. caeruleum) in the Buffalo River System. Genetica 2013; 141:75-88. [DOI: 10.1007/s10709-013-9707-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/14/2013] [Indexed: 12/01/2022]
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146
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Araya-Anchetta A, Scoles GA, Giles J, Busch JD, Wagner DM. Hybridization in natural sympatric populations of Dermacentor ticks in northwestern North America. Ecol Evol 2013; 3:714-24. [PMID: 23531531 PMCID: PMC3605858 DOI: 10.1002/ece3.496] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 01/04/2013] [Accepted: 01/08/2013] [Indexed: 11/06/2022] Open
Abstract
Hybridization in ticks has been described in a handful of species and mostly as a result of laboratory experiments. We used 148 AFLP loci to describe putative hybridization events between D. andersoni and D. variabilis in sympatric populations from northwestern North America. Recently, D. variabilis has expanded its range westward into the natural range of D. andersoni. Using a sample of 235 D. andersoni and 62 D. variabilis, we identified 31 individuals as putative hybrids: four F2 individuals and 27 backcrosses to D. andersoni (as defined by NewHybrids). We found no evidence of hybrids backcrossing into D. variabilis. Furthermore, all hybrids presented 16S mtDNA signatures characteristic of D. andersoni, which indicates the directionality of the hybrid crosses: female D. andersoni × male D. variabilis. We also discovered 13 species-specific AFLP fragments for D. andersoni. These loci were found to have a decreased occurrence in the putative hybrids and were absent altogether in D. variabilis samples. AFLP profiles were also used to determine the levels of genetic population structure and gene flow among nine populations of D. andersoni and three of D. variabilis. Genetic structure exists in both species (D. andersoni, ΦST = 0.110; D. variabilis, ΦST = 0.304) as well as significant estimates of isolation by distance (D. andersoni, ρ = 0.066, P = 0.001; D. variabilis, ρ = 0.729, P = 0.001).
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Affiliation(s)
- A Araya-Anchetta
- Center for Microbial Genetics and Genomics, Northern Arizona University 1298 S. Knoles Dr., ARD Building, Flagstaff, AZ, 86011
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147
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Anton KA, Ward JR, Cruzan MB. Pollinator-mediated selection on floral morphology: evidence for transgressive evolution in a derived hybrid lineage. J Evol Biol 2013; 26:660-73. [PMID: 23331370 DOI: 10.1111/jeb.12083] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/10/2012] [Accepted: 11/23/2012] [Indexed: 11/28/2022]
Abstract
Hybridization between closely related lineages is a mechanism that might promote substantive changes in phenotypic traits of descendants, resulting in transgressive evolution. Interbreeding between divergent but morphologically similar lineages can produce exceptional phenotypes, but the potential for transgressive variation to facilitate long-term trait changes in derived hybrid lineages has received little attention. We compare pollinator-mediated selection on transgressive floral traits in both early-generation and derived hybrid lineages of the Piriqueta cistoides ssp. caroliniana complex. The bowl-shaped flowers of morphotypes in this complex have similar gross morphologies and attract a common suite of small insect pollinators. However, they are defined by significant differences in characters that generate pollinator interest and visitation, including floral area and petal separation. In common garden experiments, patterns of pollen deposition in early-generation recombinant hybrids indicate that Piriqueta's pollinators favour flowers with greater area and reduced petal separation. Changes in floral morphology in derived hybrid lineages are consistent with predictions from selection gradients, but the magnitude of change is limited relative to the range of transgressive variation. These results suggest that hybridization provides variation for evolution of divergent floral traits. However, the potential for extreme transgressive variants to contribute to phenotypic shifts may be limited due to reduced heritability, evolutionary constraints or fitness trade-offs.
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Affiliation(s)
- K A Anton
- Department of Biology, Portland State University, Portland, OR, USA
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148
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Govindarajulu R, Hughes CE, Alexander PJ, Bailey CD. The complex evolutionary dynamics of ancient and recent polyploidy in Leucaena (Leguminosae; Mimosoideae). AMERICAN JOURNAL OF BOTANY 2011; 98:2064-76. [PMID: 22130273 DOI: 10.3732/ajb.1100260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
PREMISE OF THE STUDY The evolutionary history of Leucaena has been impacted by polyploidy, hybridization, and divergent allopatric species diversification, suggesting that this is an ideal group to investigate the evolutionary tempo of polyploidy and the complexities of reticulation and divergence in plant diversification. METHODS Parsimony- and ML-based phylogenetic approaches were applied to 105 accessions sequenced for six sequence characterized amplified region-based nuclear encoded loci, nrDNA ITS, and four cpDNA regions. Hypotheses for the origin of tetraploid species were inferred using results derived from a novel species tree and established gene tree methods and from data on genome sizes and geographic distributions. RESULTS The combination of comprehensively sampled multilocus DNA sequence data sets and a novel methodology provide strong resolution and support for the origins of all five tetraploid species. A minimum of four allopolyploidization events are required to explain the origins of these species. The origin(s) of one tetraploid pair (L. involucrata/L. pallida) can be equally explained by two unique allopolyploidizations or a single event followed by divergent speciation. CONCLUSIONS Alongside other recent findings, a comprehensive picture of the complex evolutionary dynamics of polyploidy in Leucaena is emerging that includes paleotetraploidization, diploidization of the last common ancestor to Leucaena, allopatric divergence among diploids, and recent allopolyploid origins for tetraploid species likely associated with human translocation of seed. These results provide insights into the role of divergence and reticulation in a well-characterized angiosperm lineage and into traits of diploid parents and derived tetraploids (particularly self-compatibility and year-round flowering) favoring the formation and establishment of novel tetraploids combinations.
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149
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Govindarajulu R, Hughes CE, Bailey CD. Phylogenetic and population genetic analyses of diploid Leucaena (Leguminosae; Mimosoideae) reveal cryptic species diversity and patterns of divergent allopatric speciation. AMERICAN JOURNAL OF BOTANY 2011; 98:2049-2063. [PMID: 22123714 DOI: 10.3732/ajb.1100259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Leucaena comprises 17 diploid species, five tetraploid species, and a complex series of hybrids whose evolutionary histories have been influenced by human seed translocation, cultivation, and subsequent spontaneous hybridization. Here we investigated patterns of evolutionary divergence among diploid Leucaena through comprehensively sampled multilocus phylogenetic and population genetic approaches to address species delimitation, interspecific relationships, hybridization, and the predominant mode of speciation among diploids. METHODS Parsimony- and maximum-likelihood-based phylogenetic approaches were applied to 59 accessions sequenced for six SCAR-based nuclear loci, nrDNA ITS, and four cpDNA regions. Population genetic comparisons included 1215 AFLP loci representing 42 populations and 424 individuals. RESULTS Phylogenetic results provided a well-resolved hypothesis of divergent species relationships, recovering previously recognized clades of diploids as well as newly resolved relationships. Phylogenetic and population genetic assessments identified two cryptic species that are consistent with geography and morphology. CONCLUSIONS Findings from this study highlight the importance and utility of multilocus data in the recovery of complex evolutionary histories. The results are consistent with allopatric divergence representing the predominant mode of speciation among diploid Leucaena. These findings contrast with the potential hybrid origin of several tetraploid species and highlight the importance of human translocation of seed to the origin of these tetraploids. The recognition of one previously unrecognized species (L. cruziana) and the elevation of another taxon (L. collinsii subsp. zacapana) to specific status (L. zacapana) is consistent with a growing number of newly diagnosed species from neotropical seasonally dry forests, suggesting these communities harbor greater species diversity than previously recognized.
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150
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Blair AC, Blumenthal D, Hufbauer RA. Hybridization and invasion: an experimental test with diffuse knapweed (Centaurea diffusa Lam.). Evol Appl 2011; 5:17-28. [PMID: 25568026 DOI: 10.1111/j.1752-4571.2011.00203.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/25/2011] [Indexed: 11/29/2022] Open
Abstract
A number of studies have suggested a link between hybridization and invasion. In this study, we experimentally test the potential for hybridization to influence invasion through a greenhouse common garden study. Diffuse knapweed (DK) (Centaurea diffusa Lam.) was introduced to North America with admixture from spotted knapweed (SK) (Centaurea stoebe subsp. stoebe L.). Comparisons between North American DK (including hybrid phenotypes) and native (European) DK in a common garden did not reveal enhanced performance or increased phenotypic variance, suggesting that pre-introduction hybridization or, more generally, post-introduction evolutionary change has not significantly contributed to the invasion of DK. In contrast, early generation hybrids [artificially created Backcross 1 (BC1) plants] exhibited increased variance for eight of the examined traits, and greater leaf and reproductive shoot production when compared to North American DK. Individual BC1 lines differed for several traits, suggesting the importance of the cross for drawing conclusions from such comparisons. When compared to the parental species (DK and SK), the BC1 plants were not transgressive for any of the measured traits. Overall, these findings suggest that if diploid SK is introduced to North America, interspecific hybridization has the potential to result in even more aggressive invaders.
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Affiliation(s)
- Amy C Blair
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA
| | - Dana Blumenthal
- USDA-ARS, Rangeland Resources Research Unit Fort Collins, CO, USA
| | - Ruth A Hufbauer
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA
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