1
|
Boughman JW, Servedio MR. The ecological stage maintains preference differentiation and promotes speciation. Ecol Lett 2022; 25:926-938. [DOI: 10.1111/ele.13970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/12/2021] [Accepted: 12/31/2021] [Indexed: 12/19/2022]
Affiliation(s)
- Janette W. Boughman
- Department of Integrative Biology; Ecology, Evolution & Behavior Program Michigan State University East Lansing Michigan USA
| | - Maria R. Servedio
- Department of Biology University of North Carolina Chapel Hill North Carolina USA
| |
Collapse
|
2
|
Wen G, Fu J. Isolation and reconnection: Demographic history and multiple contact zones of the green odorous frog (Odorrana margaretae) around the Sichuan Basin. Mol Ecol 2021; 30:4103-4117. [PMID: 34145663 DOI: 10.1111/mec.16021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/27/2021] [Accepted: 06/10/2021] [Indexed: 01/25/2023]
Abstract
The green odorous frog (Odorrana margaretae) displays a circular distribution around the Sichuan Basin of western China and possesses multiple replicate hybrid zones between lineages with high levels of divergence. To gain an understanding of the speciation process, we obtained 1540 SNPs from 29 populations and 227 individuals using ddRAD sequencing. Population structure analysis revealed three groups within the species: the West, North & South, and East groups. Demographic inference showed that they were initially isolated at ~2 million years ago, and subsequent post-glacial expansion produced the current circular distribution with four secondary contact zones. Hybridization in those zones involved lineages with various levels of divergence and produced greatly different patterns of introgression. Contact zones between the East and North & South groups (E-S and E-N) had contrast admixture levels but both showed a general lack of potential barrier loci. Meanwhile, the reconnection of the West and North & South groups produced two contact zones along the rim of the Basin. The S-W zone had extensive admixture while the N-W zone had limited admixture within a narrow geographic distance. Both showed substantial barrier effects, and a large number of potential barrier loci were shared. We also detected strong coupling among these loci. The N-W hybrid zone involved two highly-diverged lineages (FST = 0.704) and many loci have reached fixation around the hybrid zone. This study system offers a unique opportunity to understand the dynamics of introgression in contact zones and the architecture of reproductive isolation at different stages of speciation.
Collapse
Affiliation(s)
- Guannan Wen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jinzhong Fu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.,Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| |
Collapse
|
3
|
Capblancq T, Després L, Mavárez J. Genetic, morphological and ecological variation across a sharp hybrid zone between two alpine butterfly species. Evol Appl 2020; 13:1435-1450. [PMID: 32684968 PMCID: PMC7359832 DOI: 10.1111/eva.12925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 12/02/2019] [Accepted: 12/09/2019] [Indexed: 11/26/2022] Open
Abstract
Identifying the mechanisms involved in the formation and maintenance of species is a central question in evolutionary biology, and distinguishing the selective drivers of populations' divergence from demographic processes is of particular interest to better understand the speciation process. Hybrid zones are recognized to provide ideal places to investigate the genetic architecture of speciation and to identify the mechanisms allowing diverging species to maintain their integrity in the face of gene flow. Here, we studied two alpine butterfly species, Coenonympha macromma and C. gardetta, which can be found flying together and hybridizing in narrow contact zones in the southern French Alps. We characterized the genomic composition of individuals, their morphology and their local habitat requirements, within and around a hybrid zone. Genetic diversity analysis at 794 SNPs revealed that all individuals within the hybrid zone were highly admixed, which was not the case outside the hybrid zone. Cline analysis showed that, despite ongoing hybridization, 56 out of 122 loci differentially fixed or nearly so between the two species were impermeable to introgression across the sharp hybrid zone (9 km wide). We also found concordance in cline position and width among genetic, morphological and environmental variation, suggesting a coupling of different reproductive barriers. Habitat characteristics such as the presence of trees and shrubs and the start of the growing season were strongly associated with the genetic variation, and we found evidence of divergence at genetic markers associated with morphology and physiology, putatively involved in visual or environmental reproductive isolation. We discuss the various behavioural and ecological factors that might interplay to maintain current levels of divergence and gene flow between this species pair.
Collapse
Affiliation(s)
- Thibaut Capblancq
- Laboratoire d’Écologie AlpineUMR UGA‐USMB‐CNRS 5553Université Grenoble AlpesGrenobleFrance
- Department of Plant BiologyUniversity of VermontBurlingtonVTUSA
| | - Laurence Després
- Laboratoire d’Écologie AlpineUMR UGA‐USMB‐CNRS 5553Université Grenoble AlpesGrenobleFrance
| | - Jesús Mavárez
- Laboratoire d’Écologie AlpineUMR UGA‐USMB‐CNRS 5553Université Grenoble AlpesGrenobleFrance
- Departamento de Ciencias Biológicas y AmbientalesUniversidad Jorge Tadeo LozanoBogotáColombia
| |
Collapse
|
4
|
Batalha-Filho H, Maldonado-Coelho M, Miyaki CY. Historical climate changes and hybridization shaped the evolution of Atlantic Forest spinetails (Aves: Furnariidae). Heredity (Edinb) 2019; 123:675-693. [PMID: 31123344 DOI: 10.1038/s41437-019-0234-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 01/23/2023] Open
Abstract
Combining phylogeographic approaches and hybrid zone inference in a single framework is a robust way to depict respectively the biogeographic history of lineages and the evolutionary processes responsible for speciation. Here, we studied the spatiotemporal patterns of diversification and characterize the hybrid zone between two Atlantic Forest spinetails (Synallaxis ruficapilla and Synallaxis cinerea) using mitochondrial DNA and nuclear (autosomal and Z-linked) genes. We consistently recovered divergence between and within the two species during the late Pliocene and Pleistocene using an isolation with migration model. Also, our results indicate distinct levels of introgression among lineages. Ecological niche models and demographic inferences, used to infer range distributions throughout the late Quaternary, were not consistent with the hypothesis of a large river as a primary barrier responsible for the divergence of the two species. Instead, a scenario of isolation and divergence followed by geographic expansion and admixture as a consequence of Quaternary climatic oscillations was supported. Paleomodels also were not consistent with the idea that the hybrid zone originated in primary differentiation and favor a secondary contact scenario. Model fitting indicated that clines of different loci spanning the hybrid zone are coincident and concordant. The narrow cline for one Z-linked locus could be indicative of some form of post-zygotic selection hindering genetic homogenization between the two species.
Collapse
Affiliation(s)
| | | | - Cristina Yumi Miyaki
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| |
Collapse
|
5
|
Morales-Rozo A, Tenorio EA, Carling MD, Cadena CD. Origin and cross-century dynamics of an avian hybrid zone. BMC Evol Biol 2017; 17:257. [PMID: 29246108 PMCID: PMC5732383 DOI: 10.1186/s12862-017-1096-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 11/27/2017] [Indexed: 01/07/2023] Open
Abstract
Background Characterizations of the dynamics of hybrid zones in space and time can give insights about traits and processes important in population divergence and speciation. We characterized a hybrid zone between tanagers in the genus Ramphocelus (Aves, Thraupidae) located in southwestern Colombia. We evaluated whether this hybrid zone originated as a result of secondary contact or of primary differentiation, and described its dynamics across time using spatial analyses of molecular, morphological, and coloration data in combination with paleodistribution modeling. Results Models of potential historical distributions based on climatic data and genetic signatures of demographic expansion suggested that the hybrid zone likely originated following secondary contact between populations that expanded their ranges out of isolated areas in the Quaternary. Concordant patterns of variation in phenotypic characters across the hybrid zone and its narrow extent are suggestive of a tension zone, maintained by a balance between dispersal and selection against hybrids. Estimates of phenotypic cline parameters obtained using specimens collected over nearly a century revealed that, in recent decades, the zone appears to have moved to the east and to higher elevations, and may have become narrower. Genetic variation was not clearly structured along the hybrid zone, but comparisons between historical and contemporary specimens suggested that temporal changes in its genetic makeup may also have occurred. Conclusions Our data suggest that the hybrid zone likey resulted from secondary contact between populations. The observed changes in the hybrid zone may be a result of sexual selection, asymmetric gene flow, or environmental change. Electronic supplementary material The online version of this article (doi: 10.1186/s12862-017-1096-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Andrea Morales-Rozo
- Laboratorio de Biología Evolutiva de Vertebrados, Departamento de Ciencias Biológicas, Universidad de Los Andes, Bogotá, Colombia.,Programa de Biología y Museo de Historia Natural, Universidad de los Llanos, Sede Barcelona, Villavicencio, Colombia
| | - Elkin A Tenorio
- Laboratorio de Biología Evolutiva de Vertebrados, Departamento de Ciencias Biológicas, Universidad de Los Andes, Bogotá, Colombia.,Calima: Fundación para la Investigación de la Biodiversidad y Conservación en el Trópico, Cali, Colombia
| | - Matthew D Carling
- Cornell Laboratory of Ornithology, Cornell University, Ithaca, NY, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - Carlos Daniel Cadena
- Laboratorio de Biología Evolutiva de Vertebrados, Departamento de Ciencias Biológicas, Universidad de Los Andes, Bogotá, Colombia.
| |
Collapse
|
6
|
Enciso-Romero J, Pardo-Díaz C, Martin SH, Arias CF, Linares M, McMillan WO, Jiggins CD, Salazar C. Evolution of novel mimicry rings facilitated by adaptive introgression in tropical butterflies. Mol Ecol 2017; 26:5160-5172. [PMID: 28777894 DOI: 10.1111/mec.14277] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/25/2017] [Accepted: 07/31/2017] [Indexed: 12/25/2022]
Abstract
Understanding the genetic basis of phenotypic variation and the mechanisms involved in the evolution of adaptive novelty, especially in adaptive radiations, is a major goal in evolutionary biology. Here, we used whole-genome sequence data to investigate the origin of the yellow hindwing bar in the Heliconius cydno radiation. We found modular variation associated with hindwing phenotype in two narrow noncoding regions upstream and downstream of the cortex gene, which was recently identified as a pigmentation pattern controller in multiple species of Heliconius. Genetic variation at each of these modules suggests an independent control of the dorsal and ventral hindwing patterning, with the upstream module associated with the ventral phenotype and the downstream module with the dorsal one. Furthermore, we detected introgression between H. cydno and its closely related species Heliconius melpomene in these modules, likely allowing both species to participate in novel mimicry rings. In sum, our findings support the role of regulatory modularity coupled with adaptive introgression as an elegant mechanism by which novel phenotypic combinations can evolve and fuel an adaptive radiation.
Collapse
Affiliation(s)
- Juan Enciso-Romero
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | - Carolina Pardo-Díaz
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | - Simon H Martin
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Carlos F Arias
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia.,Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
| | - Mauricio Linares
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Camilo Salazar
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá D.C, Colombia
| |
Collapse
|
7
|
Arias CF, Giraldo N, McMillan WO, Lamas G, Jiggins CD, Salazar C. A new subspecies in a Heliconius butterfly adaptive radiation (Lepidoptera: Nymphalidae). Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlw010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
8
|
McKenzie JL, Bucking C, Moreira A, Schulte PM. Intrinsic reproductive isolating mechanisms in the maintenance of a hybrid zone between ecologically divergent subspecies. J Evol Biol 2017; 30:848-864. [PMID: 28190270 DOI: 10.1111/jeb.13055] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/24/2017] [Accepted: 02/06/2017] [Indexed: 11/29/2022]
Abstract
Understanding factors involved in maintaining stable hybrid zones is important for predicting the ultimate fate of the interacting taxa, but the relative importance of mechanisms such as ecological selection and intrinsic reproductive isolation remains unclear. Most studies of reproductive isolation in hybrid zones have focused either on zones with strongly bimodal patterns in genotype or phenotype frequencies, with relatively strong isolation, or unimodal zones with relatively weak isolation, whereas less is known about more intermediate classes of hybrid zone. Here, we utilize a hybrid zone of this intermediate type occurring between northern and southern subspecies of Atlantic killifish, Fundulus heteroclitus, to identify isolating mechanisms playing a role in maintaining this type of zone. The two subspecies differ in environmental tolerance, and we found some evidence of microhabitat preference between subspecies within a small tidal creek at the centre of the hybrid zone. There was also an association between sex, mitochondrial genotype and habitat within this creek. Fertilization success did not differ between consubspecific and heterosubspecific crosses, but hatching success was significantly lower for crosses involving southern males and northern females, and crosses between southern females and northern males had altered developmental rates. Southern females and northern males showed patterns consistent with positive assortative mating. Together, these results indicate a role for a combination of factors including assortative mating and/or early hybrid inviability in the maintenance of this hybrid zone and suggest that hybrid zones with intermediate levels of reproductive isolation are likely to be maintained by multiple interacting isolating mechanisms.
Collapse
Affiliation(s)
- J L McKenzie
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Centre for Aquaculture and Environmental Research, Fisheries and Oceans Canada, West Vancouver, BC, Canada
| | - C Bucking
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - A Moreira
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - P M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
9
|
Natural Selection and Genetic Diversity in the Butterfly Heliconius melpomene. Genetics 2016; 203:525-41. [PMID: 27017626 PMCID: PMC4858797 DOI: 10.1534/genetics.115.183285] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/21/2016] [Indexed: 11/18/2022] Open
Abstract
A combination of selective and neutral evolutionary forces shape patterns of genetic diversity in nature. Among the insects, most previous analyses of the roles of drift and selection in shaping variation across the genome have focused on the genus Drosophila A more complete understanding of these forces will come from analyzing other taxa that differ in population demography and other aspects of biology. We have analyzed diversity and signatures of selection in the neotropical Heliconius butterflies using resequenced genomes from 58 wild-caught individuals of Heliconius melpomene and another 21 resequenced genomes representing 11 related species. By comparing intraspecific diversity and interspecific divergence, we estimate that 31% of amino acid substitutions between Heliconius species are adaptive. Diversity at putatively neutral sites is negatively correlated with the local density of coding sites as well as nonsynonymous substitutions and positively correlated with recombination rate, indicating widespread linked selection. This process also manifests in significantly reduced diversity on longer chromosomes, consistent with lower recombination rates. Although hitchhiking around beneficial nonsynonymous mutations has significantly shaped genetic variation in H. melpomene, evidence for strong selective sweeps is limited overall. We did however identify two regions where distinct haplotypes have swept in different populations, leading to increased population differentiation. On the whole, our study suggests that positive selection is less pervasive in these butterflies as compared to fruit flies, a fact that curiously results in very similar levels of neutral diversity in these very different insects.
Collapse
|
10
|
Arias CF, Van Belleghem S, McMillan WO. Genomics at the evolving species boundary. CURRENT OPINION IN INSECT SCIENCE 2016; 13:7-15. [PMID: 27436548 DOI: 10.1016/j.cois.2015.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/07/2015] [Indexed: 06/06/2023]
Abstract
Molecular studies on hybridization date back to Dobzhansky who compared chromosomal banding patterns to determine if interspecific gene flow occurred in nature [1]. Now, the advent of high-throughput sequencing provides increasingly fine insights into genomic differentiation between incipient taxa that are changing our view of adaptation and speciation and the links between the two. Empirical data from hybridizing taxa demonstrate highly heterogeneous patterns of genomic differentiation. Although underlining reasons for this heterogeneity are complex, studies of hybridizing taxa offers some of the best insights into the regions of the genome under divergent selection and the role these regions play in species boundaries. The challenge moving forward is to develop a better theoretical framework that fully leverages these powerful natural experiments.
Collapse
Affiliation(s)
- Carlos F Arias
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Panamá, Panama; Biology Program, Faculty of Natural Science and Mathematics, Universidad del Rosario, Carrera 24 # 63c-69, Bogotá 111221, Colombia
| | - Steven Van Belleghem
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Panamá, Panama; Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom; Department of Biology, Center for Applied Tropical Ecology and Conservation, University of Puerto Rico, Rio Piedras, Puerto Rico
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Panamá, Panama.
| |
Collapse
|
11
|
Li LF, Wang HY, Pang D, Liu Y, Liu B, Xiao HX. Phenotypic and genetic evidence for ecological speciation of Aquilegia japonica and A. oxysepala. THE NEW PHYTOLOGIST 2014; 204:1028-1040. [PMID: 25117915 DOI: 10.1111/nph.12967] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Natural selection is thought to be a driving force that can cause the evolution of reproductive isolation. The genus Aquilegia is a model system to address how natural selection promotes the process of speciation. Morphological differences between A. oxysepala, A. japonica and their hybrids were quantified for two vegetative (plant height and leaf area) and three floral morphological (sepal area, corolla length and diameter) traits. We also evaluated the genetic variability of the two species and their hybrids based on two chloroplast (1225 bp), four nuclear (5811 bp) genes and 15 microsatellites. Our results revealed that differentiation of A. japonica and A. oxysepala at the ecological and morphological levels also involved divergence at the genetic level. In addition, the analysis of nucleotide variation patterns showed that the two species possessed numerous fixation sites at nuclear genes gAA4, gA7 and gAA12. Furthermore, we found that all of the phenotypic hybrids also showed a genetically admixed ancestry. These findings suggest that natural selection has indeed facilitated the formation of distinct genetic variation patterns in the two Aquilegia species and habitat adaptation has been driving the ecologically based evolution of reproductive isolation.
Collapse
Affiliation(s)
- Lin-Feng Li
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, 130024, China
| | | | | | | | | | | |
Collapse
|
12
|
Reproductive isolation related to mimetic divergence in the poison frog Ranitomeya imitator. Nat Commun 2014; 5:4749. [PMID: 25158807 DOI: 10.1038/ncomms5749] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/21/2014] [Indexed: 01/20/2023] Open
Abstract
In a mimetic radiation--when a single species evolves to resemble different model species--mimicry can drive within-species morphological diversification, and, potentially, speciation. While mimetic radiations have occurred in a variety of taxa, their role in speciation remains poorly understood. We study the Peruvian poison frog Ranitomeya imitator, a species that has undergone a mimetic radiation into four distinct morphs. Using a combination of colour-pattern analysis, landscape genetics and mate-choice experiments, we show that a mimetic shift in R. imitator is associated with a narrow phenotypic transition zone, neutral genetic divergence and assortative mating, suggesting that divergent selection to resemble different model species has led to a breakdown in gene flow between these two populations. These results extend the effects of mimicry on speciation into a vertebrate system and characterize an early stage of speciation where reproductive isolation between mimetic morphs is incomplete but evident.
Collapse
|
13
|
Arias CF, Salazar C, Rosales C, Kronforst MR, Linares M, Bermingham E, McMillan WO. Phylogeography of Heliconius cydno and its closest relatives: disentangling their origin and diversification. Mol Ecol 2014; 23:4137-52. [PMID: 24962067 DOI: 10.1111/mec.12844] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 06/14/2014] [Accepted: 06/16/2014] [Indexed: 11/28/2022]
Abstract
The origins of the extraordinary diversity within the Neotropics have long fascinated biologists and naturalists. Yet, the underlying factors that have given rise to this diversity remain controversial. To test the relative importance of Quaternary climatic change and Neogene tectonic and paleogeographic reorganizations in the generation of biodiversity, we examine intraspecific variation across the Heliconius cydno radiation and compare this variation to that within the closely related Heliconius melpomene and Heliconius timareta radiations. Our data, which consist of both mtDNA and genome-scan data from nearly 2250 amplified fragment length polymorphism (AFLP) loci, reveal a complex history of differentiation and admixture at different geographic scales. Both mtDNA and AFLP phylogenies suggest that H. timareta and H. cydno are probably geographic extremes of the same radiation that probably diverged from H. melpomene prior to the Pliocene-Pleistocene boundary, consistent with hypotheses of diversification that rely on geological events in the Pliocene. The mtDNA suggests that this radiation originated in Central America or the northwestern region of South America, with a subsequent colonization of the eastern and western slopes of the Andes. Our genome-scan data indicate significant admixture among sympatric H. cydno/H. timareta and H. melpomene populations across the extensive geographic ranges of the two radiations. Within H. cydno, both mtDNA and AFLP data indicate significant population structure at local scales, with strong genetic differences even among adjacent H. cydno colour pattern races. These genetic patterns highlight the importance of past geoclimatic events, intraspecific gene flow, and local population differentiation in the origin and establishment of new adaptive forms.
Collapse
Affiliation(s)
- Carlos F Arias
- Department of Biology, McGill University, 1205 Ave. Dr. Penfield, Montreal, QC, Canada, H3A 1B1; Smithsonian Tropical Research Institute, Apartado 0843-03092, Panamá, Panamá
| | | | | | | | | | | | | |
Collapse
|
14
|
Van der Niet T, Peakall R, Johnson SD. Pollinator-driven ecological speciation in plants: new evidence and future perspectives. ANNALS OF BOTANY 2014; 113:199-211. [PMID: 24418954 PMCID: PMC3890394 DOI: 10.1093/aob/mct290] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 11/17/2013] [Indexed: 05/07/2023]
Abstract
BACKGROUND The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. SCOPE This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of 'pollination ecotypes', (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation.
Collapse
Affiliation(s)
- Timotheüs Van der Niet
- Naturalis Biodiversity Center, P.O. Box 9514, 2300 RA, Leiden, The Netherlands
- Leiden University, Section Botany, P.O. Box 9514, 2300 RA, Leiden, The Netherlands
- School of Life Sciences, University of KwaZulu Natal, P/Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
| | - Rod Peakall
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Steven D. Johnson
- School of Life Sciences, University of KwaZulu Natal, P/Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
| |
Collapse
|
15
|
Mallet J, Dasmahapatra KK. Hybrid zones and the speciation continuum in Heliconius butterflies. Mol Ecol 2013; 21:5643-5. [PMID: 23310964 DOI: 10.1111/mec.12058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tropical butterflies in the genus Heliconius have long been models in the study of the stages of speciation. Heliconius are unpalatable to predators, and many species are notable for multiple geographic populations with striking warning colour pattern differences associated with Müllerian mimicry. A speciation continuum is evident in Heliconius hybrid zones. Examples range from hybrid zones across which (a) there is little genetic differentiation other than at mimicry loci, but where hybrids are common, (b) to 'bimodal' hybrid zones with strong genetic divergence and few hybrids, (c) through to 'good' sympatric species, with hybridization extremely rare or absent. Now, in this issue of Molecular Ecology, Arias et al. (2012) have found an intermediate case in Colombian Heliconius cydno showing evidence for assortative mating and molecular differences, but where hybrids are abundant.
Collapse
Affiliation(s)
- James Mallet
- Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK.
| | | |
Collapse
|