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Ekar JM, Price DK, Johnson MA, Stacy EA. Varieties of the highly dispersible and hypervariable tree, Metrosideros polymorpha, differ in response to mechanical stress and light across a sharp ecotone. AMERICAN JOURNAL OF BOTANY 2019; 106:1106-1115. [PMID: 31330066 DOI: 10.1002/ajb2.1331] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 05/28/2019] [Indexed: 05/26/2023]
Abstract
PREMISE The drivers of isolation between sympatric populations of long-lived and highly dispersible conspecific plants are not well understood. In the Hawaiian Islands, the landscape-dominant tree, Metrosideros polymorpha, displays extraordinary phenotypic differences among sympatric varieties despite high dispersibility of its pollen and seeds, thereby presenting a unique opportunity to investigate how disruptive selection alone can maintain incipient forms. Stenophyllous M. polymorpha var. newellii is a recently evolved tree endemic to the waterways of eastern Hawai'i Island that shows striking neutral genetic differentiation from its ancestor, wet-forest M. polymorpha var. glaberrima, despite sympatry of these forms. We looked for evidence for, and drivers of, differential local adaptation of these varieties across the range of M. polymorpha var. newellii. METHODS For paired populations of these varieties, we compared seedling performance under contrasting light conditions and a strong water current characteristic of the riparian zone. We also conducted a reciprocal transplant experiment and contrasted adult leaf anatomy. RESULTS Results suggest that the riparian zone is harsh and that selection involving the mechanical stress of rushing water, and secondarily, light, led to significant reciprocal immigrant inviability in adjacent forest and riparian environments. The strongest adaptive divergence between varieties was seen in leaves and seedlings from the site with the sharpest ecotone, coincident with the strongest genetic isolation of M. polymorpha var. newellii observed previously. CONCLUSIONS These findings suggest that disruptive selection across a sharp ecotone contributes to the maintenance of an incipient riparian ecotype from within a continuous population of a long-lived and highly dispersible tree species.
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Affiliation(s)
- Jill M Ekar
- The Microbial and Plant Genomics Institute, University of Minnesota-Twin Cities, 1500 Gortner Avenue, Saint Paul, Minnesota, 55108, USA
- Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, Hawai'i, 96720, USA
| | - Donald K Price
- Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, Hawai'i, 96720, USA
- School of Life Sciences, University of Nevada Las Vegas, 4505 South Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Melissa A Johnson
- USDA-Agricultural Research Service, Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center, Hilo, Hawai'i, 96720, USA
| | - Elizabeth A Stacy
- Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, Hawai'i, 96720, USA
- School of Life Sciences, University of Nevada Las Vegas, 4505 South Maryland Parkway, Las Vegas, Nevada, 89154, USA
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Zhang GJ, Hu HH, Gao TG, Gilbert MG, Jin XF. Convergent origin of the narrowly lanceolate leaf in the genus Aster-with special reference to an unexpected discovery of a new Aster species from East China. PeerJ 2019; 7:e6288. [PMID: 30701132 PMCID: PMC6348959 DOI: 10.7717/peerj.6288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/15/2018] [Indexed: 11/20/2022] Open
Abstract
Narrowly lanceolate leaves occur frequently in the genus Aster. It was often employed as a distinguishing character in the taxonomy of this genus. The origin of this particular leaf shape, however, has never been investigated using comparative methods. In this study, we reconstructed a comprehensive phylogeny that includes most species of Aster with narrowly lanceolate leaf. We then gathered data on riparian habitats and the presence or absence of narrowly lanceolate leaves, and investigated the evolutionary association between them in a phylogenetic context. Our analysis indicated that the species with narrowly lanceolate leaves are nested in unrelated lineages of the genus Aster, implying that they originated independently several times. Using Pagel’s comparative method of discrete data, we demonstrated a significant correlation between riparian habitats and narrowly lanceolate leaves. We further inferred the sequence of transition of the two characters. This analysis indicated that the sequence of evolution of riparian habitat and narrowly lanceolate leaf form was usually uncertain, but some positive results showed that the occurrence of riparian habitats may not precede the evolution of narrowly lanceolate leaf form. This study provided new insights into the adaptive evolution in a mega-diverse family. In addition, Aster tonglingensis, an unexpected new species with narrowly lanceolate leaves, was discovered and established based on the evidence from morphology, micromorphology and molecular phylogeny.
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Affiliation(s)
- Guo-Jin Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Science, Beijing, China
| | - Hai-Hua Hu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Science, Beijing, China
| | - Tian-Gang Gao
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Science, Beijing, China
| | | | - Xiao-Feng Jin
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
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Kobayashi H, Haino Y, Iwasaki T, Tezuka A, Nagano AJ, Shimada S. ddRAD-seq based phylogeographic study of Sargassum thunbergii (Phaeophyceae, Heterokonta) around Japanese coast. MARINE ENVIRONMENTAL RESEARCH 2018; 140:104-113. [PMID: 29895505 DOI: 10.1016/j.marenvres.2018.05.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 06/08/2023]
Abstract
Using genome-wide SNP data obtained from high-throughput techniques based on double digest restriction site-associated DNA sequencing (ddRAD-seq), we elucidated the migration history and genetic diversity of the Japanese population of the ecologically important brown seaweed Sargassum thunbergii (Mertens ex Roth) Kuntze. STRUCTURE and NeighborNet analyses showed a clear genetic differentiation among populations of four geographic regions: Kyushu (POP1); Sea of Japan (POP2); Hokkaido and Tohoku (POP3); and Pacific coast from Kyushu to Kanto (POP4). Approximate Bayesian Computation (ABC) analysis indicated that POP4 diverged first, followed by the separation between POP2 (the largest effective population size) and POP3; POP1 was the last to form, shaped by the mixture of POP2 (73%) and POP4 (27%). High genetic diversity was detected in POP1 and POP2, whereas low genetic diversity was detected in POP3 and POP4. These results indicated that S. thunbergii populations of Kyushu and the Sea of Japan might have been maintained as large and stable populations gathered different lineages from China, Korea and/or Japan.
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Affiliation(s)
- Honoka Kobayashi
- Faculty of Core Research, Natural Science Division, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo, 112-8610, Japan
| | - Yuka Haino
- Faculty of Core Research, Natural Science Division, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo, 112-8610, Japan
| | - Takaya Iwasaki
- Faculty of Science, Kanagawa University, Tsuchiya 2946, Hiratsuka, Kanagawa, 259-1293, Japan
| | - Ayumi Tezuka
- Faculty of Agriculture, Ryukoku University, Yokotani 1-5, Seta Ohe-cho, Otsu, Shiga, 520-2194, Japan
| | - Atsushi J Nagano
- Faculty of Agriculture, Ryukoku University, Yokotani 1-5, Seta Ohe-cho, Otsu, Shiga, 520-2194, Japan
| | - Satoshi Shimada
- Faculty of Core Research, Natural Science Division, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo, 112-8610, Japan.
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Morphological and genetic differences between Coptis japonica var. anemonifolia H. Ohba and Coptis japonica var. major Satake in Hokuriku area. J Nat Med 2018; 72:514-522. [DOI: 10.1007/s11418-018-1179-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/18/2018] [Indexed: 11/25/2022]
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Yoichi W, Kawamata I, Matsuki Y, Suyama Y, Uehara K, Ito M. Phylogeographic analysis suggests two origins for the riparian azalea Rhododendron indicum (L.) Sweet. Heredity (Edinb) 2018; 121:594-604. [PMID: 29479059 DOI: 10.1038/s41437-018-0064-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 11/09/2022] Open
Abstract
Ecological speciation is an important factor in the diversification of plants. The distribution of the woody species Rhododendron indicum, which grows along rivers and is able to withstand water flow when rivers flood (i.e. it is a rheophyte), is disjunct, in contrast to the widespread distribution of its relative, Rhododendron kaempferi. This study aimed to elucidate the phylogenetic relationships between R. indicum and R. kaempferi and the evolutionary processes that gave rise to them. The sequences of three non-coding chloroplast DNA regions (total length 1977 bp) were obtained from 21 populations covering the ranges of the two species. In addition, genome-wide SNPs were genotyped from 20 populations using a genotyping by sequencing method. Leaf morphologies were measured for eight representative populations. Two chloroplast DNA haplotypes, which were detected in R. indicum, were shared between the two species. Genome-wide SNPs identified two lineages in R. indicum and these lineages did not constitute a monophyletic group. Each of these two lineages was related to geographically close populations of R. kaempferi. Leaf morphology, which is a characteristic feature in rheophytes, was not differentiated between the two lineages in R. indicum. The morphological similarity between the two heterogeneous lineages may be a result of parallel evolution from R. kaempferi or of introgressive hybridization between the species due to strong selective pressure imposed by flooding.
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Affiliation(s)
- Watanabe Yoichi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo, Chiba, 271-8510, Japan.
| | - Izumi Kawamata
- Faculty of Horticulture, Chiba University, Matsudo 648, Matsudo, Chiba, 271-8510, Japan
| | - Yu Matsuki
- Graduate School of Agricultural Science, Tohoku University, Naruko-onsen Yomogida 232-3, Osaki, Miyagi, 989-6711, Japan
| | - Yoshihisa Suyama
- Graduate School of Agricultural Science, Tohoku University, Naruko-onsen Yomogida 232-3, Osaki, Miyagi, 989-6711, Japan
| | - Koichi Uehara
- College of Liberal Arts and Sciences, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba, 263-8522, Japan
| | - Motomi Ito
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan
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Zhao Y, Yin G, Pan Y, Gong X. Ecological and Genetic Divergences with Gene Flow of Two Sister Species ( Leucomeris decora and Nouelia insignis) Driving by Climatic Transition in Southwest China. FRONTIERS IN PLANT SCIENCE 2018; 9:31. [PMID: 29422911 PMCID: PMC5789531 DOI: 10.3389/fpls.2018.00031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/09/2018] [Indexed: 06/08/2023]
Abstract
Understanding of the processes of divergence and speciation is a major task for biodiversity researches and may offer clearer insight into mechanisms generating biological diversity. Here, we employ an integrative approach to explore genetic and ecological differentiation of Leucomeris decora and Nouelia insignis distributed allopatrically along the two sides of the biogeographic boundary 'Tanaka Line' in Southwest China. We addressed these questions using ten low-copy nuclear genes and nine plastid DNA regions sequenced among individuals sampled from 28 populations across their geographic ranges in China. Phylogenetic, coalescent-based population genetic analyses, approximate Bayesian computation (ABC) framework and ecological niche models (ENMs) were conducted. We identified a closer phylogenetic relationship in maternal lineage of L. decora with N. insignis than that between L. decora and congeneric Leucomeris spectabilis. A deep divergence between the two species was observed and occurred at the boundary between later Pliocene and early Pleistocene. However, the evidence of significant chloroplast DNA gene flow was also detected between the marginal populations of L. decora and N. insignis. Niche models and statistical analyses showed significant ecological differentiation, and two nuclear loci among the ten nuclear genes may be under divergent selection. These integrative results imply that the role of climatic shift from Pliocene to Pleistocene may be the prominent factor for the divergence of L. decora and N. insignis, and population expansion after divergence may have given rise to chloroplast DNA introgression. The divergence was maintained by differential selection despite in the face of gene flow.
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Affiliation(s)
- Yujuan Zhao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Genshen Yin
- Department of Biological Science and Technology, Kunming University, Kunming, China
| | - Yuezhi Pan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Paudel Y, Madsen O, Megens HJ, Frantz LAF, Bosse M, Crooijmans RPMA, Groenen MAM. Copy number variation in the speciation of pigs: a possible prominent role for olfactory receptors. BMC Genomics 2015; 16:330. [PMID: 25896665 PMCID: PMC4413995 DOI: 10.1186/s12864-015-1449-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 03/09/2015] [Indexed: 12/02/2022] Open
Abstract
Background Unraveling the genetic mechanisms associated with reduced gene flow between genetically differentiated populations is key to understand speciation. Different types of structural variations (SVs) have been found as a source of genetic diversity in a wide range of species. Previous studies provided detailed knowledge on the potential evolutionary role of SVs, especially copy number variations (CNVs), between well diverged species of e.g. primates. However, our understanding of their significance during ongoing speciation processes is limited due to the lack of CNV data from closely related species. The genus Sus (pig and its close relatives) which started to diverge ~4 Mya presents an excellent model for studying the role of CNVs during ongoing speciation. Results In this study, we identified 1408 CNV regions (CNVRs) across the genus Sus. These CNVRs encompass 624 genes and were found to evolve ~2.5 times faster than single nucleotide polymorphisms (SNPs). The majority of these copy number variable genes are olfactory receptors (ORs) known to play a prominent role in food foraging and mate recognition in Sus. Phylogenetic analyses, including novel Bayesian analysis, based on CNVRs that overlap ORs retain the well-accepted topology of the genus Sus whereas CNVRs overlapping genes other than ORs show evidence for random drift and/or admixture. Conclusion We hypothesize that inter-specific variation in copy number of ORs provided the means for rapid adaptation to different environments during the diversification of the genus Sus in the Pliocene. Furthermore, these regions might have acted as barriers preventing massive gene flow between these species during the multiple hybridization events that took place later in the Pleistocene suggesting a possible prominent role of ORs in the ongoing Sus speciation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1449-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yogesh Paudel
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands. .,Current address: Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070, Basel, Switzerland.
| | - Ole Madsen
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
| | - Hendrik-Jan Megens
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
| | - Laurent A F Frantz
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
| | - Mirte Bosse
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
| | - Richard P M A Crooijmans
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
| | - Martien A M Groenen
- Animal Breeding and Genomics Centre, Wageningen University, 6700 AH, Wageningen, The Netherlands.
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Incipient radiation within the dominant Hawaiian tree Metrosideros polymorpha. Heredity (Edinb) 2014; 113:334-42. [PMID: 24824285 DOI: 10.1038/hdy.2014.47] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 03/23/2014] [Accepted: 04/01/2014] [Indexed: 01/19/2023] Open
Abstract
Although trees comprise a primary component of terrestrial species richness, the drivers and temporal scale of divergence in trees remain poorly understood. We examined the landscape-dominant tree, Metrosideros polymorpha, for variation at nine microsatellite loci across 23 populations on young Hawai'i Island, sampling each of the island's five varieties throughout its full geographic range. For four varieties, principal coordinate analysis revealed strong clustering of populations by variety across the 10 430 km(2) island, indicating partitioning of the species into multiple evolutionarily significant units. The single island-endemic form, riparian var. newellii, showed especially strong differentiation from other varieties despite occurring in sympatry with other varieties and likely evolved from a bog form on the oldest volcano, Kohala, within the past 500 000 years. Along with comparable riparian forms on other Pacific Islands, var. newellii appears to represent parallel incipient ecological speciation within Metrosideros. Greater genetic distance among the more common varieties on the oldest volcano and an inverse relationship between allelic diversity and substrate age appear consistent with colonization of Hawai'i Island by older, partially diverged varieties followed by increased hybridization among varieties on younger volcanoes. This study demonstrates that broad population-level sampling is required to uncover patterns of diversification within a ubiquitous and long-lived tree species. Hawaiian Metrosideros appears to be a case of incipient radiation in trees and thus should be useful for studies of divergence and the evolution of reproductive isolating barriers at the early stages of speciation.
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