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Hlavatá K, Záveská E, Leong-Škorničková J, Pouch M, Poulsen AD, Šída O, Khadka B, Mandáková T, Fér T. Ancient hybridization and repetitive element proliferation in the evolutionary history of the monocot genus Amomum (Zingiberaceae). FRONTIERS IN PLANT SCIENCE 2024; 15:1324358. [PMID: 38708400 PMCID: PMC11066291 DOI: 10.3389/fpls.2024.1324358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/12/2024] [Indexed: 05/07/2024]
Abstract
Genome size variation is a crucial aspect of plant evolution, influenced by a complex interplay of factors. Repetitive elements, which are fundamental components of genomic architecture, often play a role in genome expansion by selectively amplifying specific repeat motifs. This study focuses on Amomum, a genus in the ginger family (Zingiberaceae), known for its 4.4-fold variation in genome size. Using a robust methodology involving PhyloNet reconstruction, RepeatExplorer clustering, and repeat similarity-based phylogenetic network construction, we investigated the repeatome composition, analyzed repeat dynamics, and identified potential hybridization events within the genus. Our analysis confirmed the presence of four major infrageneric clades (A-D) within Amomum, with clades A-C exclusively comprising diploid species (2n = 48) and clade D encompassing both diploid and tetraploid species (2n = 48 and 96). We observed an increase in the repeat content within the genus, ranging from 84% to 89%, compared to outgroup species with 75% of the repeatome. The SIRE lineage of the Ty1-Copia repeat superfamily was prevalent in most analyzed ingroup genomes. We identified significant difference in repeatome structure between the basal Amomum clades (A, B, C) and the most diverged clade D. Our investigation revealed evidence of ancient hybridization events within Amomum, coinciding with a substantial proliferation of multiple repeat groups. This finding supports the hypothesis that ancient hybridization is a driving force in the genomic evolution of Amomum. Furthermore, we contextualize our findings within the broader context of genome size variations and repeatome dynamics observed across major monocot lineages. This study enhances our understanding of evolutionary processes within monocots by highlighting the crucial roles of repetitive elements in shaping genome size and suggesting the mechanisms that drive these changes.
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Affiliation(s)
- Kristýna Hlavatá
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
| | - Eliška Záveská
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
- Institute of Botany, Czech Academy of Science, Průhonice, Czechia
| | - Jana Leong-Škorničková
- Herbarium, Singapore Botanic Gardens, National Parks Board, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Milan Pouch
- Central European Institute of Technology, Masaryk University, Brno, Czechia
- National Center for Biomolecular Research (NCBR), Masaryk University, Kamenice, Czechia
| | - Axel Dalberg Poulsen
- Tropical Diversity Section, Royal Botanic Garden Edinburgh, Edinburgh, United Kingdom
| | - Otakar Šída
- Department of Botany, National Museum in Prague, Prague, Czechia
| | - Bijay Khadka
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
| | - Terezie Mandáková
- Central European Institute of Technology, Masaryk University, Brno, Czechia
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
| | - Tomáš Fér
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
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2
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de Tomás C, Vicient CM. The Genomic Shock Hypothesis: Genetic and Epigenetic Alterations of Transposable Elements after Interspecific Hybridization in Plants. EPIGENOMES 2023; 8:2. [PMID: 38247729 PMCID: PMC10801548 DOI: 10.3390/epigenomes8010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/21/2023] [Accepted: 12/24/2023] [Indexed: 01/23/2024] Open
Abstract
Transposable elements (TEs) are major components of plant genomes with the ability to change their position in the genome or to create new copies of themselves in other positions in the genome. These can cause gene disruption and large-scale genomic alterations, including inversions, deletions, and duplications. Host organisms have evolved a set of mechanisms to suppress TE activity and counter the threat that they pose to genome integrity. These includes the epigenetic silencing of TEs mediated by a process of RNA-directed DNA methylation (RdDM). In most cases, the silencing machinery is very efficient for the vast majority of TEs. However, there are specific circumstances in which TEs can evade such silencing mechanisms, for example, a variety of biotic and abiotic stresses or in vitro culture. Hybridization is also proposed as an inductor of TE proliferation. In fact, the discoverer of the transposons, Barbara McClintock, first hypothesized that interspecific hybridization provides a "genomic shock" that inhibits the TE control mechanisms leading to the mobilization of TEs. However, the studies carried out on this topic have yielded diverse results, showing in some cases a total absence of mobilization or being limited to only some TE families. Here, we review the current knowledge about the impact of interspecific hybridization on TEs in plants and the possible implications of changes in the epigenetic mechanisms.
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Affiliation(s)
| | - Carlos M. Vicient
- Centre for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Cerdanyola del Vallès, 08193 Barcelona, Spain
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3
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Reifová R, Ament-Velásquez SL, Bourgeois Y, Coughlan J, Kulmuni J, Lipinska AP, Okude G, Stevison L, Yoshida K, Kitano J. Mechanisms of Intrinsic Postzygotic Isolation: From Traditional Genic and Chromosomal Views to Genomic and Epigenetic Perspectives. Cold Spring Harb Perspect Biol 2023; 15:a041607. [PMID: 37696577 PMCID: PMC10547394 DOI: 10.1101/cshperspect.a041607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Intrinsic postzygotic isolation typically appears as reduced viability or fertility of interspecific hybrids caused by genetic incompatibilities between diverged parental genomes. Dobzhansky-Muller interactions among individual genes, and chromosomal rearrangements causing problems with chromosome synapsis and recombination in meiosis, have both long been considered as major mechanisms behind intrinsic postzygotic isolation. Recent research has, however, suggested that the genetic basis of intrinsic postzygotic isolation can be more complex and involves, for example, overall divergence of the DNA sequence or epigenetic changes. Here, we review the mechanisms of intrinsic postzygotic isolation from genic, chromosomal, genomic, and epigenetic perspectives across diverse taxa. We provide empirical evidence for these mechanisms, discuss their importance in the speciation process, and highlight questions that remain unanswered.
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Affiliation(s)
- Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | | | - Yann Bourgeois
- DIADE, University of Montpellier, CIRAD, IRD, 34090 Montpellier, France
| | - Jenn Coughlan
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, Connecticut 06520, USA
| | - Jonna Kulmuni
- Institute for Biodiversity and Ecosystem Dynamics, Department of Evolutionary and Population Biology, University of Amsterdam, 1012 Amsterdam, The Netherlands
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, 00100 Helsinki, Finland
| | - Agnieszka P Lipinska
- Department of Algal Development and Evolution, Max Planck Institute for Biology, 72076 Tuebingen, Germany
- CNRS, UMR 8227, Integrative Biology of Marine Models, Sorbonne Université, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Genta Okude
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Laurie Stevison
- Department of Biological Sciences, Auburn University, Auburn, Alabama 36849, USA
| | - Kohta Yoshida
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Jun Kitano
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
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4
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Hartig N, Seibt KM, Heitkam T. How to start a LINE: 5' switching rejuvenates LINE retrotransposons in tobacco and related Nicotiana species. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023. [PMID: 36965091 DOI: 10.1111/tpj.16208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/10/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
By contrast to their conserved mammalian counterparts, plant long interspersed nuclear elements (LINEs) are highly variable, splitting into many low-copy families. Curiously, LINE families from the retrotransposable element (RTE) clade retain a stronger sequence conservation and hence reach higher copy numbers. The cause of this RTE-typical property is not yet understood, but would help clarify why some transposable elements are removed quickly, whereas others persist in plant genomes. Here, we bring forward a detailed study of RTE LINE structure, diversity and evolution in plants. For this, we argue that the nightshade family is the ideal taxon to follow the evolutionary trajectories of RTE LINEs, given their high abundance, recent activity and partnership to non-autonomous elements. Using bioinformatic, cytogenetic and molecular approaches, we detect 4029 full-length RTE LINEs across the Solanaceae. We finely characterize and manually curate a core group of 458 full-length LINEs in allotetraploid tobacco, show an integration event after polyploidization and trace hybridization by RTE LINE composition of parental genomes. Finally, we reveal the role of the untranslated regions (UTRs) as causes for the unique RTE LINE amplification and evolution pattern in plants. On the one hand, we detected a highly conserved motif at the 3' UTR, suggesting strong selective constraints acting on the RTE terminus. On the other hand, we observed successive rounds of 5' UTR cycling, constantly rejuvenating the promoter sequences. This interplay between exchangeable promoters and conserved LINE bodies and 3' UTR likely allows RTE LINEs to persist and thrive in plant genomes.
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Affiliation(s)
- Nora Hartig
- Faculty of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Kathrin M Seibt
- Faculty of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Tony Heitkam
- Faculty of Botany, Technische Universität Dresden, 01069, Dresden, Germany
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5
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Liu P, Cuerda-Gil D, Shahid S, Slotkin RK. The Epigenetic Control of the Transposable Element Life Cycle in Plant Genomes and Beyond. Annu Rev Genet 2022; 56:63-87. [DOI: 10.1146/annurev-genet-072920-015534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Within the life cycle of a living organism, another life cycle exists for the selfish genome inhabitants, which are called transposable elements (TEs). These mobile sequences invade, duplicate, amplify, and diversify within a genome, increasing the genome's size and generating new mutations. Cells act to defend their genome, but rather than permanently destroying TEs, they use chromatin-level repression and epigenetic inheritance to silence TE activity. This level of silencing is ephemeral and reversible, leading to a dynamic equilibrium between TE suppression and reactivation within a host genome. The coexistence of the TE and host genome can also lead to the domestication of the TE to serve in host genome evolution and function. In this review, we describe the life cycle of a TE, with emphasis on how epigenetic regulation is harnessed to control TEs for host genome stability and innovation.
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Affiliation(s)
- Peng Liu
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - Diego Cuerda-Gil
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
- Graduate Program in the Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA
| | - Saima Shahid
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - R. Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
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6
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Berbel-Filho WM, Pacheco G, Lira MG, Garcia de Leaniz C, Lima SMQ, Rodríguez-López CM, Zhou J, Consuegra S. Additive and non-additive epigenetic signatures of natural hybridisation between fish species with different mating systems. Epigenetics 2022; 17:2356-2365. [PMID: 36082413 PMCID: PMC9665120 DOI: 10.1080/15592294.2022.2123014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hybridization is a major source of evolutionary innovation. In plants, epigenetic mechanisms can help to stabilize hybrid genomes and contribute to reproductive isolation, but the relationship between genetic and epigenetic changes in animal hybrids is unclear. We analysed the relationship between genetic background and methylation patterns in natural hybrids of two genetically divergent fish species with different mating systems, Kryptolebias hermaphroditus (self-fertilizing) and K. ocellatus (outcrossing). Co-existing parental species displayed highly distinct genetic (SNPs) and methylation patterns (37,000 differentially methylated cytosines). Hybrids had predominantly intermediate methylation patterns (88.5% of the sites) suggesting additive effects, as expected from hybridization between genetically distant species. The large number of differentially methylated cytosines between hybrids and parental species (n = 5,800) suggests that hybridization may play a role in increasing genetic and epigenetic variation. Although most of the observed epigenetic variation was additive and had a strong genetic component, we also found a small percentage of non-additive, potentially stochastic, methylation differences that might act as an evolutionary bet-hedging strategy and increase fitness under environmental instability.
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Affiliation(s)
- Waldir M Berbel-Filho
- Centre for Sustainable Aquatic Research, Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - George Pacheco
- Section for Evolutionary Genomics, The Globe Institute, Faculty of Health and Medical Sciences, University of Copenhagen, 1353 Copenhagen, Denmark
| | - Mateus G Lira
- Laboratório de Ictiologia Sistemática e Evolutiva, Departamento de Botânica e Zoologia, Universidade Federal do Rio Grande, Natal, Brazil
| | - Carlos Garcia de Leaniz
- Centre for Sustainable Aquatic Research, Department of Biosciences, College of Science, Swansea University, Swansea, UK
| | - Sergio M Q Lima
- Laboratório de Ictiologia Sistemática e Evolutiva, Departamento de Botânica e Zoologia, Universidade Federal do Rio Grande, Natal, Brazil
| | - Carlos M Rodríguez-López
- Environmental Epigenetics and Genetics Group, Department of Horticulture, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, USA
| | - Jia Zhou
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Sofia Consuegra
- Centre for Sustainable Aquatic Research, Department of Biosciences, College of Science, Swansea University, Swansea, UK
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García G, Gutiérrez V, Ríos N. Living in Temporary Ponds Loading Giant Genomes: The Neotropical Annual Killifish Genus Austrolebias as New Outstanding Evolutionary Model. Front Genet 2022; 13:903683. [PMID: 35795213 PMCID: PMC9251178 DOI: 10.3389/fgene.2022.903683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/05/2022] [Indexed: 12/02/2022] Open
Abstract
The term Annual killifish describes a short-lived and amazing group of vertebrates inhabiting temporary ponds exposed to an extremely variable environment during its short lifespan in South America and Africa, leading to the death of the entire adult population during the dry season. Austrolebias is a specious genus of the family Rivulidae, with ∼58 currently recognized species, extensively distributed in the temperate Neotropical region. Herein, we reviewed different aspects of the evolutionary biology with emphasis on the genome dynamic linked to the burst speciation process in this genus. Austrolebias constitutes an excellent model to study the genomic evolutionary processes underlying speciation events, since all the species of this genus analyzed so far share an unusually large genome size, with an average DNA content of 5.95 ± 0.45 picograms per diploid cell (mean C-value of about 2.98 pg). The drastic nuclear DNA–increasing would be associated with a considerable proportion of transposable elements (TEs) found in the Austrolebias genomes. The genomic proportion of the moderately repetitive DNA in the A. charrua genome represents approximately twice (45%) the amount of the repetitive components of the highly related sympatric and syntopic rivulinae taxon Cynopoecilus melanotaenia (25%), as well as from other rivulids and actinopterygian fish. These events could explain the great genome instability, the high genetic diversity, chromosome variability, as well as the morphological diversity in species of Austrolebias. Thus, species of this genus represent new model systems linking different evolutionary processes: drastic genome increase, massive TEs genomic representation, high chromosome instability, occurrence of natural hybridization between sister species, and burst speciation events.
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Affiliation(s)
| | | | - Néstor Ríos
- Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Montevideo, Uruguay
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8
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Interspecific hybridization in tomato influences endogenous viral sRNAs and alters gene expression. Genome Biol 2022; 23:120. [PMID: 35597968 PMCID: PMC9124383 DOI: 10.1186/s13059-022-02685-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 05/09/2022] [Indexed: 11/23/2022] Open
Abstract
Background Hybridization is associated with the activation of transposable elements and changes in the patterns of gene expression leading to phenotypic changes. However, the underlying mechanisms are not well understood. Results Here, we describe the changes to the gene expression in interspecific Solanum hybrids that are associated with small RNAs derived from endogenous (para)retroviruses (EPRV). There were prominent changes to sRNA profiles in these hybrids involving 22-nt species produced in the DCL2 biogenesis pathway, and the hybridization-induced changes to the gene expression were similar to those in a dcl2 mutant. Conclusions These findings indicate that hybridization leads to activation of EPRV, perturbation of small RNA profiles, and, consequently, changes in the gene expression. Such hybridization-induced variation in the gene expression could increase the natural phenotypic variation in natural evolution or in breeding for agriculture. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02685-z.
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9
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Gantuz M, Morales A, Bertoldi MV, Ibañez VN, Duarte PF, Marfil CF, Masuelli RW. Hybridization and polyploidization effects on LTR-retrotransposon activation in potato genome. JOURNAL OF PLANT RESEARCH 2022; 135:81-92. [PMID: 34674075 DOI: 10.1007/s10265-021-01354-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Hybridization and polyploidization are major forces in plant evolution and potatoes are not an exception. It is proposed that the proliferation of Long Terminal Repeat-retrotransposons (LTR-RT) is related to genome reorganization caused by hybridization and/or polyploidization. The main purpose of the present work was to evaluate the effect of interspecific hybridization and polyploidization on the activation of LTR-RT. We evaluated the proliferation of putative active LTR-RT in a diploid hybrid between the cultivated potato Solanum tuberosum and the wild diploid potato species S. kurtzianum, allotetraploid lines derived from this interspecific hybrid and S. kurtzianum autotetraploid lines (ktz-autotetraploid) using the S-SAP (sequence-specific amplified polymorphism) technique and normalized copy number determination by qPCR. Twenty-nine LTR-RT copies were activated in the hybrid and present in the allotetraploid lines. Major LTR-RT activity was detected in Copia-27, Copia-12, Copia-14 and, Gypsy-22. According to our results, LTR-RT copies were activated principally in the hybrid, there was no activation in allotetraploid lines and only one copy was activated in the autotetraploid.
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Affiliation(s)
- Magdalena Gantuz
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina.
| | - Andrés Morales
- Instituto Nacional de Tecnología Agropecuaria (INTA), Luján de Cuyo, Mendoza, Argentina
| | - María Victoria Bertoldi
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Verónica Noé Ibañez
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Paola Fernanda Duarte
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Carlos Federico Marfil
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Ricardo Williams Masuelli
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina.
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10
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Serrato-Capuchina A, Wang J, Earley E, Peede D, Isbell K, Matute DR. Paternally Inherited P-Element Copy Number Affects the Magnitude of Hybrid Dysgenesis in Drosophila simulans and D. melanogaster. Genome Biol Evol 2020; 12:808-826. [PMID: 32339225 PMCID: PMC7313671 DOI: 10.1093/gbe/evaa084] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2020] [Indexed: 12/16/2022] Open
Abstract
Transposable elements (TEs) are repetitive regions of DNA that are able to self-replicate and reinsert themselves throughout host genomes. Since the discovery of TEs, a prevalent question has been whether increasing TE copy number has an effect on the fitness of their hosts. P-elements (PEs) in Drosophila are a well-studied TE that has strong phenotypic effects. When a female without PEs (M) is crossed to a male with them (P), the resulting females are often sterile, a phenomenon called hybrid dysgenesis (HD). Here, we used short- and long-read sequencing to infer the number of PEs in the genomes of dozens of isofemale lines from two Drosophila species and measured whether the magnitude of HD was correlated with the number of PEs in the paternal genome. Consistent with previous reports, we find evidence for a positive correlation between the paternal PE copy number and the magnitude of HD in progeny from ♀M × ♂ P crosses for both species. Other crosses are not affected by the number of PE copies. We also find that the correlation between the strength of HD and PE copy number differs between species, which suggests that there are genetic differences that might make some genomes more resilient to the potentially deleterious effects of TEs. Our results suggest that PE copy number interacts with other factors in the genome and the environment to cause HD and that the importance of these interactions is species specific.
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Affiliation(s)
| | - Jeremy Wang
- Genetics Department, University of North Carolina, Chapel Hill
| | - Eric Earley
- Genomics in Public Health and Medicine RTI International, Research Triangle Park, North Carolina
| | - David Peede
- Biology Department, University of North Carolina, Chapel Hill
| | - Kristin Isbell
- Biology Department, University of North Carolina, Chapel Hill
| | - Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill
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11
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Zhang GW, Wang L, Chen H, Guan J, Wu Y, Zhao J, Luo Z, Huang W, Zuo F. Promoter hypermethylation of PIWI/piRNA pathway genes associated with diminished pachytene piRNA production in bovine hybrid male sterility. Epigenetics 2020; 15:914-931. [PMID: 32141383 DOI: 10.1080/15592294.2020.1738026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Hybrid male sterility (HMS) is a postzygotic reproductive isolation mechanism that enforces speciation. A bovine example of HMS is the yattle (also called dzo), an interspecies hybrid of taurine cattle (Bos taurus) and yak (Bos grunniens). The molecular mechanisms underlying HMS of yattle are not well understood. Epigenetic modifications of DNA methylation and P-element induced wimpy testis (PIWI)-interacting RNA (piRNAs) are important regulators in spermatogenesis. In this study, we investigated DNA methylation patterns and piRNA expression in adult testes in hybrid infertile yattle bulls and fertile cattle and yak bulls using whole genome bisulphite-seq and small RNA-seq. Promoter hypermethylation in yattle were associated with DNA methylation involved in gamete generation, piRNA metabolic processes, spermatogenesis, and spermatid development (P < 2.6 × 10-5). Male infertility in yattle was associated with the promoter hypermethylation-associated silencing of PIWI/piRNA pathway genes including PIWIL1, DDX4, PLD6, MAEL, FKBP6, TDRD1 and TDRD5. The downstream effects of silencing these genes were diminished production of 29- to 31- nucleotide pachytene piRNAs in yattle testes. Hypermethylation events at transposable element loci (LINEs, SINEs, and LTRs) were found in yattle. LINE-derived prepachytene piRNAs increased and SINE-derived prepachytene piRNAs were reduced in yattle testes. Our data suggests that DNA methylation affects the PIWI/piRNA pathway and is involved in gene expression and pachytene piRNA production during spermatogenesis in bovine HMS. DNA hypermethylation and disruption of piRNA production contributed to unsuccessful germ cell development that may drive bovine HMS.
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Affiliation(s)
- Gong-Wei Zhang
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Ling Wang
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Huiyou Chen
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Jiuqiang Guan
- Yak Research Institution, Sichuan Academy of Grassland Science , Chengdu, Sichuan, China
| | - Yuhui Wu
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Jianjun Zhao
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Zonggang Luo
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Wenming Huang
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
| | - Fuyuan Zuo
- College of Animal Science, Southwest University , Chongqing, China.,Beef Cattle Engineering and Technology Research Center of Chongqing, Southwest University , Chongqing, China
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12
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Luo K, Wang S, Fu Y, Zhou P, Huang X, Gu Q, Li W, Wang Y, Hu F, Liu S. Rapid genomic DNA variation in newly hybridized carp lineages derived from Cyprinus carpio (♀) × Megalobrama amblycephala (♂). BMC Genet 2019; 20:87. [PMID: 31779581 PMCID: PMC6883602 DOI: 10.1186/s12863-019-0784-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/14/2019] [Indexed: 11/24/2022] Open
Abstract
Background Distant hybridization can generate changes in phenotypes and genotypes that lead to the formation of new hybrid lineages with genetic variation. In this study, the establishment of two bisexual fertile carp lineages, including the improved diploid common carp (IDC) lineage and the improved diploid scattered mirror carp (IDMC) lineage, from the interspecific hybridization of common carp (Cyprinus carpio, 2n = 100) (♀) × blunt snout bream (Megalobrama amblycephala, 2n = 48) (♂), provided a good platform to investigate the genetic relationship between the parents and their hybrid progenies. Result In this study, we investigated the genetic variation of 12 Hox genes in the two types of improved carp lineages derived from common carp (♀) × blunt snout bream (♂). Hox gene clusters were abundant in the first generation of IDC, but most were not stably inherited in the second generation. In contrast, we did not find obvious mutations in Hox genes in the first generation of IDMC, and almost all the Hox gene clusters were stably inherited from the first generation to the second generation of IDMC. Interestingly, we found obvious recombinant clusters of Hox genes in both improved carp lineages, and partially recombinant clusters of Hox genes were stably inherited from the first generation to the second generation in both types of improved carp lineages. On the other hand, some Hox genes were gradually becoming pseudogenes, and some genes were completely pseudogenised in IDC or IDMC. Conclusions Our results provided important evidence that distant hybridization produces rapid genomic DNA changes that may or may not be stably inherited, providing novel insights into the function of hybridization in the establishment of improved lineages used as new fish resources for aquaculture.
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Affiliation(s)
- Kaikun Luo
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Shi Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Yeqing Fu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Pei Zhou
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Xuexue Huang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Qianhong Gu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Wuhui Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,Key Laboratory of Tropical and Subtropical Fisheries Resource Application and Cultivation, Ministry of Agriculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, Guangdong, People's Republic of China
| | - Yude Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Fangzhou Hu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.,College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China. .,College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, People's Republic of China.
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13
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Kotov AA, Adashev VE, Godneeva BK, Ninova M, Shatskikh AS, Bazylev SS, Aravin AA, Olenina LV. piRNA silencing contributes to interspecies hybrid sterility and reproductive isolation in Drosophila melanogaster. Nucleic Acids Res 2019; 47:4255-4271. [PMID: 30788506 PMCID: PMC6486647 DOI: 10.1093/nar/gkz130] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 12/05/2022] Open
Abstract
The piRNA pathway is an adaptive mechanism that maintains genome stability by repression of selfish genomic elements. In the male germline of Drosophila melanogaster repression of Stellate genes by piRNAs generated from Supressor of Stellate (Su(Ste)) locus is required for male fertility, but both Su(Ste) piRNAs and their targets are absent in other Drosophila species. We found that D. melanogaster genome contains multiple X-linked non-coding genomic repeats that have sequence similarity to the protein-coding host gene vasa. In the male germline, these vasa-related AT-chX repeats produce abundant piRNAs that are antisense to vasa; however, vasa mRNA escapes silencing due to imperfect complementarity to AT-chX piRNAs. Unexpectedly, we discovered AT-chX piRNAs target vasa of Drosophila mauritiana in the testes of interspecies hybrids. In the majority of hybrid flies, the testes were strongly reduced in size and germline content. A minority of hybrids maintained wild-type array of premeiotic germ cells in the testes, but in them harmful Stellate genes were derepressed due to the absence of Su(Ste) piRNAs, and meiotic failures were observed. Thus, the piRNA pathway contributes to reproductive isolation between D. melanogaster and closely related species, causing hybrid male sterility via misregulation of two different host protein factors.
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Affiliation(s)
- Alexei A Kotov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Vladimir E Adashev
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Baira K Godneeva
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Maria Ninova
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Aleksei S Shatskikh
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Sergei S Bazylev
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Alexei A Aravin
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia.,California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Ludmila V Olenina
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
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14
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Fontdevila A. Hybrid Genome Evolution by Transposition: An Update. J Hered 2019; 110:124-136. [PMID: 30107415 DOI: 10.1093/jhered/esy040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/06/2018] [Indexed: 02/02/2023] Open
Abstract
Contrary to the view that hybrids are lineages devoid of evolutionary value, a number of case studies that have been lately reported show how hybrids are at the origin of many species. Some well-documented cases demonstrate that bursts of transposition often follow hybridization, generating new genetic variability. Studies in hybrid transposition strongly suggest that epigenetic changes and divergence in piRNA pathways drive deregulation in TE landscapes. Here, I have focused on mechanisms acting in Drosophila hybrids between two cactophilic species. The results reported here show that while hybrid instability by transposition is a genome-wide event, deregulation by TE overexpression in hybrid ovaries is not a general rule. When piRNA pools of ovaries are studied, results show that TEs with parental differences higher than 2-fold in their piRNA amounts are not more commonly deregulated in hybrids than TEs with similar levels, partially discrediting the generality of the maternal cytotype hypothesis. Some promising results on the piRNA pathway global failure hypothesis, which states that accumulated divergence of piRNA effector proteins is responsible for hybrid TE deregulation, have also been obtained. Altogether, these results suggest that TE deregulation might be driven by several interacting mechanisms. A natural scenario is proposed in which genome instability by transposition leads to hybrid genome reorganization. Small hybrid populations, subjected to natural selection helped by genetic drift, evolve new adaptations adapted to novel environments. The final step is either introgression or even a new hybrid species.
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Affiliation(s)
- Antonio Fontdevila
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Bellaterra, Spain
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15
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Phenotypic, Genetic, and Cytogenetic Evidence of Hybridization Between Species of Trans-Andean Tamarins (Genus Saguinus). INT J PRIMATOL 2018. [DOI: 10.1007/s10764-018-0044-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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16
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Romero-Soriano V, Modolo L, Lopez-Maestre H, Mugat B, Pessia E, Chambeyron S, Vieira C, Garcia Guerreiro MP. Transposable Element Misregulation Is Linked to the Divergence between Parental piRNA Pathways in Drosophila Hybrids. Genome Biol Evol 2018; 9:1450-1470. [PMID: 28854624 PMCID: PMC5499732 DOI: 10.1093/gbe/evx091] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2017] [Indexed: 12/30/2022] Open
Abstract
Interspecific hybridization is a genomic stress condition that leads to the activation of transposable elements (TEs) in both animals and plants. In hybrids between Drosophila buzzatii and Drosophila koepferae, mobilization of at least 28 TEs has been described. However, the molecular mechanisms underlying this TE release remain poorly understood. To give insight on the causes of this TE activation, we performed a TE transcriptomic analysis in ovaries (notorious for playing a major role in TE silencing) of parental species and their F1 and backcrossed (BC) hybrids. We find that 15.2% and 10.6% of the expressed TEs are deregulated in F1 and BC1 ovaries, respectively, with a bias toward overexpression in both cases. Although differences between parental piRNA (Piwi-interacting RNA) populations explain only partially these results, we demonstrate that piRNA pathway proteins have divergent sequences and are differentially expressed between parental species. Thus, a functional divergence of the piRNA pathway between parental species, together with some differences between their piRNA pools, might be at the origin of hybrid instabilities and ultimately cause TE misregulation in ovaries. These analyses were complemented with the study of F1 testes, where TEs tend to be less expressed than in D. buzzatii. This can be explained by an increase in piRNA production, which probably acts as a defence mechanism against TE instability in the male germline. Hence, we describe a differential impact of interspecific hybridization in testes and ovaries, which reveals that TE expression and regulation are sex-biased.
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Affiliation(s)
- Valèria Romero-Soriano
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Spain
| | - Laurent Modolo
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Hélène Lopez-Maestre
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Bruno Mugat
- Institut de Génétique Humaine, UMR9002, CNRS-Université de Montpellier, France
| | - Eugénie Pessia
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Séverine Chambeyron
- Institut de Génétique Humaine, UMR9002, CNRS-Université de Montpellier, France
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Maria Pilar Garcia Guerreiro
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Spain
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17
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Moving Speciation Genetics Forward: Modern Techniques Build on Foundational Studies in Drosophila. Genetics 2018; 207:825-842. [PMID: 29097397 DOI: 10.1534/genetics.116.187120] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/23/2017] [Indexed: 12/12/2022] Open
Abstract
The question of how new species evolve has been examined at every level, from macroevolutionary patterns of diversification to molecular population genetic analyses of specific genomic regions between species pairs. Drosophila has been at the center of many of these research efforts. Though our understanding of the speciation process has grown considerably over the past few decades, very few genes have been identified that contribute to barriers to reproduction. The development of advanced molecular genetic and genomic methods provides promising avenues for the rapid discovery of more genes that contribute to speciation, particularly those involving prezygotic isolation. The continued expansion of tools and resources, especially for species other than Drosophila melanogaster, will be most effective when coupled with comparative approaches that reveal the genetic basis of reproductive isolation across a range of divergence times. Future research programs in Drosophila have high potential to answer long-standing questions in speciation. These include identifying the selective forces that contribute to divergence between populations and the genetic basis of traits that cause reproductive isolation. The latter can be expanded upon to understand how the genetic basis of reproductive isolation changes over time and whether certain pathways and genes are more commonly involved.
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18
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Warren KA, Ritzman TB, Humphreys RA, Percival CJ, Hallgrímsson B, Ackermann RR. Craniomandibular form and body size variation of first generation mouse hybrids: A model for hominin hybridization. J Hum Evol 2018; 116:57-74. [PMID: 29477182 PMCID: PMC6699179 DOI: 10.1016/j.jhevol.2017.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/04/2017] [Accepted: 12/12/2017] [Indexed: 12/27/2022]
Abstract
Hybridization occurs in a number of mammalian lineages, including among primate taxa. Analyses of ancient genomes have shown that hybridization between our lineage and other archaic hominins in Eurasia occurred numerous times in the past. However, we still have limited empirical data on what a hybrid skeleton looks like, or how to spot patterns of hybridization among fossils for which there are no genetic data. Here we use experimental mouse models to supplement previous studies of primates. We characterize size and shape variation in the cranium and mandible of three wild-derived inbred mouse strains and their first generation (F1) hybrids. The three parent taxa in our analysis represent lineages that diverged over approximately the same period as the human/Neanderthal/Denisovan lineages and their hybrids are variably successful in the wild. Comparisons of body size, as quantified by long bone measurements, are also presented to determine whether the identified phenotypic effects of hybridization are localized to the cranium or represent overall body size changes. The results indicate that hybrid cranial and mandibular sizes, as well as limb length, exceed that of the parent taxa in all cases. All three F1 hybrid crosses display similar patterns of size and form variation. These results are generally consistent with earlier studies on primates and other mammals, suggesting that the effects of hybridization may be similar across very different scenarios of hybridization, including different levels of hybrid fitness. This paper serves to supplement previous studies aimed at identifying F1 hybrids in the fossil record and to introduce further research that will explore hybrid morphologies using mice as a proxy for better understanding hybridization in the hominin fossil record.
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Affiliation(s)
- Kerryn A Warren
- Department of Archaeology, University of Cape Town, South Africa; Human Evolution Research Institute, University of Cape Town, South Africa
| | - Terrence B Ritzman
- Department of Archaeology, University of Cape Town, South Africa; Human Evolution Research Institute, University of Cape Town, South Africa; Department of Neuroscience, Washington University School of Medicine, USA; School of Human Evolution and Social Change, Arizona State University, USA
| | - Robyn A Humphreys
- Department of Archaeology, University of Cape Town, South Africa; Human Evolution Research Institute, University of Cape Town, South Africa
| | - Christopher J Percival
- Department of Cell Biology and Anatomy, McCaig Institute for Bone and Joint Health, Alberta Children's Hospital Research Institute, University of Calgary, Canada; The Alberta Children's Hospital Research Institute, University of Calgary, Canada; The McCaig Institute for Bone and Joint Health, University of Calgary, Canada; Department of Anthropology, Stony Brook, USA
| | - Benedikt Hallgrímsson
- Department of Cell Biology and Anatomy, McCaig Institute for Bone and Joint Health, Alberta Children's Hospital Research Institute, University of Calgary, Canada; The Alberta Children's Hospital Research Institute, University of Calgary, Canada; The McCaig Institute for Bone and Joint Health, University of Calgary, Canada
| | - Rebecca Rogers Ackermann
- Department of Archaeology, University of Cape Town, South Africa; Human Evolution Research Institute, University of Cape Town, South Africa.
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19
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Smukowski Heil CS, DeSevo CG, Pai DA, Tucker CM, Hoang ML, Dunham MJ. Loss of Heterozygosity Drives Adaptation in Hybrid Yeast. Mol Biol Evol 2017; 34:1596-1612. [PMID: 28369610 PMCID: PMC5455960 DOI: 10.1093/molbev/msx098] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. The genomic changes that occur following hybridization that facilitate genome resolution and/or adaptation are not well understood. Here, we examine hybrid genome evolution using experimental evolution of de novo interspecific hybrid yeast Saccharomyces cerevisiae × Saccharomyces uvarum and their parentals. We evolved these strains in nutrient-limited conditions for hundreds of generations and sequenced the resulting cultures identifying numerous point mutations, copy number changes, and loss of heterozygosity (LOH) events, including species-biased amplification of nutrient transporters. We focused on a particularly interesting example, in which we saw repeated LOH at the high-affinity phosphate transporter gene PHO84 in both intra- and interspecific hybrids. Using allele replacement methods, we tested the fitness of different alleles in hybrid and S. cerevisiae strain backgrounds and found that the LOH is indeed the result of selection on one allele over the other in both S. cerevisiae and the hybrids. This is an example where hybrid genome resolution is driven by positive selection on existing heterozygosity and demonstrates that even infrequent outcrossing may have lasting impacts on adaptation.
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Affiliation(s)
| | - Christopher G DeSevo
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ
| | - Dave A Pai
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ
| | - Cheryl M Tucker
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ
| | - Margaret L Hoang
- Department of Embryology, Howard Hughes Medical Institute, Carnegie Institution, Baltimore, MD.,Department of Biology, Johns Hopkins University, Baltimore, MD
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, WA
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20
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Ren L, Cui J, Wang J, Tan H, Li W, Tang C, Qin Q, Liu S. Analyzing homoeolog expression provides insights into the rediploidization event in gynogenetic hybrids of Carassius auratus red var. × Cyprinus carpio. Sci Rep 2017; 7:13679. [PMID: 29057976 PMCID: PMC5651915 DOI: 10.1038/s41598-017-14084-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 09/18/2017] [Indexed: 11/28/2022] Open
Abstract
Rediploidization is considered to be a part of the evolutionary history of allotetraploids, and resulted in the emergence of novel epigenetic regulatory activities. To study the changing patterns of gene expression following the reduction of a genome by 50%, we used RNA-seq and quantitative real-time PCR (qPCR) to investigate total gene expression and homoeolog expression in three hybrids of a C. auratus red var. (2n = 100, ♀) (R) and C. carpio (2n = 100, ♂) (C) (i.e., F1, F18, and G4) and their original parents. A comparison of homoeolog expression between G4 and F18 identified 7 genes (0.22%) that exhibited novel R/C homoeolog expression patterns in G4, while 4 genes (0.12%) were affected by R/C homoeolog silencing. We determined the direction and extent of the homoeolog expression bias (HEB). The C-HEB genes (i.e., nrp1a and igf1) and R-HEB genes (i.e., fgf23 and esm1) provided insights into the effects of the dominance of one parental homoeolog expression on growth regulation. This dominance may contribute to the rapid growth of G4 fish. Our findings may be relevant for clarifying the relationship between growth heterosis and differences in homoeolog expression patterns.
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Affiliation(s)
- Li Ren
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Jialin Cui
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Jing Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Hui Tan
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Wuhui Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Chenchen Tang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Qinbo Qin
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China.
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China.
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21
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Dennenmoser S, Sedlazeck FJ, Iwaszkiewicz E, Li X, Altmüller J, Nolte AW. Copy number increases of transposable elements and protein-coding genes in an invasive fish of hybrid origin. Mol Ecol 2017; 26:4712-4724. [PMID: 28390096 PMCID: PMC5638112 DOI: 10.1111/mec.14134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/23/2017] [Accepted: 03/27/2017] [Indexed: 12/25/2022]
Abstract
Evolutionary dynamics of structural genetic variation in lineages of hybrid origin is not well explored, although structural mutations may increase in controlled hybrid crosses. We therefore tested whether structural variants accumulate in a fish of recent hybrid origin, invasive Cottus, relative to both parental species Cottus rhenanus and Cottus perifretum. Copy-number variation in exons of 10,979 genes was assessed using comparative genome hybridization arrays. Twelve genes showed significantly higher copy numbers in invasive Cottus compared to both parents. This coincided with increased expression for three genes related to vision, detoxification and muscle development, suggesting possible gene dosage effects. Copy number increases of putative transposons were assessed by comparative mapping of genomic DNA reads against a de novo assembly of 1,005 repetitive elements. In contrast to exons, copy number increases of repetitive elements were common (20.7%) in invasive Cottus, whereas decrease was very rare (0.01%). Among the increased repetitive elements, 53.8% occurred at higher numbers in C. perifretum compared to C. rhenanus, while only 1.4% were more abundant in C. rhenanus. This implies a biased mutational process that amplifies genetic material from one ancestor. To assess the frequency of de novo mutations through hybridization, we screened 64 laboratory-bred F2 offspring between the parental species for copy-number changes at five candidate loci. We found no evidence for new structural variants, indicating that they are too rare to be detected given our sampling scheme. Instead, they must have accumulated over more generations than we observed in a controlled cross.
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Affiliation(s)
- Stefan Dennenmoser
- Department for Evolutionary GeneticsMax‐Planck Institute for Evolutionary BiologyPlönGermany
- Institute for BiologyCarl von Ossietzky University OldenburgOldenburgGermany
| | | | - Elzbieta Iwaszkiewicz
- Department for Evolutionary GeneticsMax‐Planck Institute for Evolutionary BiologyPlönGermany
| | - Xiang‐Yi Li
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Janine Altmüller
- Cologne Center for Genomics, and Institute of Human GeneticsUniversity of CologneCologneGermany
| | - Arne W. Nolte
- Department for Evolutionary GeneticsMax‐Planck Institute for Evolutionary BiologyPlönGermany
- Institute for BiologyCarl von Ossietzky University OldenburgOldenburgGermany
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22
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Dion-Côté AM, Barbash DA. Beyond speciation genes: an overview of genome stability in evolution and speciation. Curr Opin Genet Dev 2017; 47:17-23. [PMID: 28830007 DOI: 10.1016/j.gde.2017.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/17/2017] [Accepted: 07/28/2017] [Indexed: 01/03/2023]
Abstract
Genome stability ensures individual fitness and reliable transmission of genetic information. Hybridization between diverging lineages can trigger genome instability, highlighting its potential role in post-zygotic reproductive isolation. We argue that genome instability is not merely one of several types of hybrid incompatibility, but rather that genome stability is one of the very first and most fundamental traits that can break down when two diverged genomes are combined. Future work will reveal how frequent and predictable genome instability is in hybrids, how it affects hybrid fitness, and whether it is a direct cause or consequence of speciation.
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Affiliation(s)
- Anne-Marie Dion-Côté
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States
| | - Daniel A Barbash
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States.
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Balao F, Trucchi E, Wolfe TM, Hao B, Lorenzo MT, Baar J, Sedman L, Kosiol C, Amman F, Chase MW, Hedrén M, Paun O. Adaptive sequence evolution is driven by biotic stress in a pair of orchid species (Dactylorhiza) with distinct ecological optima. Mol Ecol 2017; 26:3649-3662. [PMID: 28370647 PMCID: PMC5518283 DOI: 10.1111/mec.14123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/24/2017] [Accepted: 03/15/2017] [Indexed: 12/23/2022]
Abstract
The orchid family is the largest in the angiosperms, but little is known about the molecular basis of the significant variation they exhibit. We investigate here the transcriptomic divergence between two European terrestrial orchids, Dactylorhiza incarnata and Dactylorhiza fuchsii, and integrate these results in the context of their distinct ecologies that we also document. Clear signals of lineage-specific adaptive evolution of protein-coding sequences are identified, notably targeting elements of biotic defence, including both physical and chemical adaptations in the context of divergent pools of pathogens and herbivores. In turn, a substantial regulatory divergence between the two species appears linked to adaptation/acclimation to abiotic conditions. Several of the pathways affected by differential expression are also targeted by deviating post-transcriptional regulation via sRNAs. Finally, D. incarnata appears to suffer from insufficient sRNA control over the activity of RNA-dependent DNA polymerase, resulting in increased activity of class I transposable elements and, over time, in larger genome size than that of D. fuchsii. The extensive molecular divergence between the two species suggests significant genomic and transcriptomic shock in their hybrids and offers insights into the difficulty of coexistence at the homoploid level. Altogether, biological response to selection, accumulated during the history of these orchids, appears governed by their microenvironmental context, in which biotic and abiotic pressures act synergistically to shape transcriptome structure, expression and regulation.
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Affiliation(s)
- Francisco Balao
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Departamento de Biología Vegetal y EcologíaUniversity of SevilleSevillaSpain
| | - Emiliano Trucchi
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Department of Life Sciences and BiotechnologiesUniversity of FerraraFerraraItaly
| | - Thomas M. Wolfe
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Vienna Graduate School of Population GeneticsViennaAustria
| | - Bao‐Hai Hao
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | - Maria Teresa Lorenzo
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
- Departamento de Biología Vegetal y EcologíaUniversity of SevilleSevillaSpain
| | - Juliane Baar
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | - Laura Sedman
- Gregor Mendel Institute for Plant Molecular BiologyViennaAustria
| | - Carolin Kosiol
- Institut für PopulationsgenetikVetmeduni ViennaViennaAustria
- Centre of Biological DiversitySchool of BiologyUniversity of St AndrewsSt AndrewsUK
| | - Fabian Amman
- Department of Chromosome BiologyUniversity of ViennaViennaAustria
| | - Mark W. Chase
- Royal Botanic Gardens KewRichmondUK
- School of Plant BiologyUniversity of Western AustraliaCrawley, PerthWAAustralia
| | | | - Ovidiu Paun
- Department of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
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Identification of misexpressed genetic elements in hybrids between Drosophila-related species. Sci Rep 2017; 7:40618. [PMID: 28091568 PMCID: PMC5238404 DOI: 10.1038/srep40618] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 12/09/2016] [Indexed: 12/30/2022] Open
Abstract
Crosses between close species can lead to genomic disorders, often considered to be the cause of hybrid incompatibility, one of the initial steps in the speciation process. How these incompatibilities are established and what are their causes remain unclear. To understand the initiation of hybrid incompatibility, we performed reciprocal crosses between two species of Drosophila (D. mojavensis and D. arizonae) that diverged less than 1 Mya. We performed a genome-wide transcriptomic analysis on ovaries from parental lines and on hybrids from reciprocal crosses. Using an innovative procedure of co-assembling transcriptomes, we show that parental lines differ in the expression of their genes and transposable elements. Reciprocal hybrids presented specific gene categories and few transposable element families misexpressed relative to the parental lines. Because TEs are mainly silenced by piwi-interacting RNAs (piRNAs), we hypothesize that in hybrids the deregulation of specific TE families is due to the absence of such small RNAs. Small RNA sequencing confirmed our hypothesis and we therefore propose that TEs can indeed be major players of genome differentiation and be implicated in the first steps of genomic incompatibilities through small RNA regulation.
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Sotero-Caio CG, Platt RN, Suh A, Ray DA. Evolution and Diversity of Transposable Elements in Vertebrate Genomes. Genome Biol Evol 2017; 9:161-177. [PMID: 28158585 PMCID: PMC5381603 DOI: 10.1093/gbe/evw264] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) are selfish genetic elements that mobilize in genomes via transposition or retrotransposition and often make up large fractions of vertebrate genomes. Here, we review the current understanding of vertebrate TE diversity and evolution in the context of recent advances in genome sequencing and assembly techniques. TEs make up 4-60% of assembled vertebrate genomes, and deeply branching lineages such as ray-finned fishes and amphibians generally exhibit a higher TE diversity than the more recent radiations of birds and mammals. Furthermore, the list of taxa with exceptional TE landscapes is growing. We emphasize that the current bottleneck in genome analyses lies in the proper annotation of TEs and provide examples where superficial analyses led to misleading conclusions about genome evolution. Finally, recent advances in long-read sequencing will soon permit access to TE-rich genomic regions that previously resisted assembly including the gigantic, TE-rich genomes of salamanders and lungfishes.
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Affiliation(s)
| | - Roy N. Platt
- Department of Biological Sciences, Texas Tech University, Lubbock, TX
| | - Alexander Suh
- Department of Evolutionary Biology (EBC), Uppsala University, Uppsala, Sweden
| | - David A. Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, TX
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27
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Maciak S, Michalak K, Kale SD, Michalak P. Nucleolar Dominance and Repression of 45S Ribosomal RNA Genes in Hybrids between Xenopus borealis and X. muelleri (2n = 36). Cytogenet Genome Res 2016; 149:290-296. [PMID: 27728911 DOI: 10.1159/000450665] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2016] [Indexed: 11/19/2022] Open
Abstract
Nucleolar dominance is a dramatic disruption in the formation of nucleoli and the expression of ribosomal RNA (rRNA) genes, characteristic of some plant and animal hybrids. Here, we report that F1 hybrids produced from reciprocal crosses between 2 sister species of Xenopus clawed frogs, X. muelleri and X. borealis, undergo nucleolar dominance somewhat distinct from a pattern previously reported in hybrids between phylogenetically more distant Xenopus species. Patterns of nucleolar development, 45S rRNA expression, and gene copy inheritance were investigated using a combination of immunostaining, pyrosequencing, droplet digital PCR, flow cytometry, and epigenetic inhibition. In X. muelleri × X. borealis hybrids, typically only 1 nucleolus is formed, and 45S rRNA genes are predominantly expressed from 1 progenitor's alleles, X. muelleri, regardless of the cross-direction. These changes are accompanied by an extensive (∼80%) loss of rRNA gene copies in the hybrids relative to their parents, with the transcriptionally underdominant variant (X. borealis) being preferentially lost. Chemical treatment of hybrid larvae with a histone deacetylase inhibitor resulted in a partial derepression of the underdominant variant. Together, these observations shed light on the genetic and epigenetic basis of nucleolar dominance as an underappreciated manifestation of genetic conflicts within a hybrid genome.
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Dion-Côté AM, Symonová R, Lamaze FC, Pelikánová Š, Ráb P, Bernatchez L. Standing chromosomal variation in Lake Whitefish species pairs: the role of historical contingency and relevance for speciation. Mol Ecol 2016; 26:178-192. [PMID: 27545583 DOI: 10.1111/mec.13816] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 12/19/2022]
Abstract
The role of chromosome changes in speciation remains a debated topic, although demographic conditions associated with divergence should promote their appearance. We tested a potential relationship between chromosome changes and speciation by studying two Lake Whitefish (Coregonus clupeaformis) lineages that recently colonized postglacial lakes following allopatry. A dwarf limnetic species evolved repeatedly from the normal benthic species, becoming reproductively isolated. Lake Whitefish hybrids experience mitotic and meiotic instability, which may result from structurally divergent chromosomes. Motivated by this observation, we test the hypothesis that chromosome organization differs between Lake Whitefish species pairs using cytogenetics. While chromosome and fundamental numbers are conserved between the species (2n = 80, NF = 98), we observe extensive polymorphism of subtle karyotype traits. We describe intrachromosomal differences associated with heterochromatin and repetitive DNA, and test for parallelism among three sympatric species pairs. Multivariate analyses support the hypothesis that differentiation at the level of subchromosomal markers mostly appeared during allopatry. Yet we find no evidence for parallelism between species pairs among lakes, consistent with colonization effect or postcolonization differentiation. The reported intrachromosomal polymorphisms do not appear to play a central role in driving adaptive divergence between normal and dwarf Lake Whitefish. We discuss how chromosomal differentiation in the Lake Whitefish system may contribute to the destabilization of mitotic and meiotic chromosome segregation in hybrids, as documented previously. The chromosome structures detected here are still difficult to sequence and assemble, demonstrating the value of cytogenetics as a complementary approach to understand the genomic bases of speciation.
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Affiliation(s)
- Anne-Marie Dion-Côté
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, Québec, Canada, G1V 0A6
| | - Radka Symonová
- Research Institute for Limnology, University of Innsbruck, Mondseestraße 9, A-5310, Mondsee, Austria
| | - Fabien C Lamaze
- Ontario Institut for Cancer Research, MaRS Centre, 661 University Avenue, Suite 510, Toronto, Ontario, Canada, M5G 0A3
| | - Šárka Pelikánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, vvi, Liběchov, 277 21, Czech Republic
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, vvi, Liběchov, 277 21, Czech Republic
| | - Louis Bernatchez
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, Québec, Canada, G1V 0A6
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Homoeologue expression insights into the basis of growth heterosis at the intersection of ploidy and hybridity in Cyprinidae. Sci Rep 2016; 6:27040. [PMID: 27265401 PMCID: PMC4893626 DOI: 10.1038/srep27040] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 05/12/2016] [Indexed: 11/09/2022] Open
Abstract
Hybridization and polyploidization are considered important driving forces that form new epigenetic regulations. To study the changing patterns of expression accompanying hybridization and polyploidization, we used RNA-seq and qRT-PCR to investigate global expression and homoeologue expression in diploid and tetraploid hybrids of Carassius auratus red var. (♀) (R) and Cyprinus carpio (♂) (C). By comparing the relative expression levels between the hybrids and their parents, we defined the expression level dominance (ELD) and homoeologue expression bias (HEB) in liver tissue. The results showed that polyploidization contributed to the conversion of homoeologue ELD. In addition, hybridization had more effect on the change in HEB than polyploidization, while polyploidization had more effect on the change of global gene expression than hybridization. Meanwhile, similar expression patterns were found in growth-related genes. The results suggested that hybridization and polyploidization result in differential degrees of maternal HEB in three tissues (liver, muscle and ovary) tested. The results of this study will increase our understanding of the underlying regulation mechanism of rapid growth in diploid hybrids and allotetraploids. The differential degrees of global expression and homoeologue expression contribute to growth heterosis in newly formed hybrids, ensuring the on-going success of allotetraploid speciation.
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30
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Senerchia N, Felber F, North B, Sarr A, Guadagnuolo R, Parisod C. Differential introgression and reorganization of retrotransposons in hybrid zones between wild wheats. Mol Ecol 2016; 25:2518-28. [DOI: 10.1111/mec.13515] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/24/2015] [Accepted: 11/30/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Natacha Senerchia
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
| | - François Felber
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
- Musée et Jardins Botaniques Cantonaux; 1007 Lausanne Switzerland
| | - Béatrice North
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
| | - Anouk Sarr
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
| | - Roberto Guadagnuolo
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany; Institute of Biology; University of Neuchâtel; 2000 Neuchâtel Switzerland
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31
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Romero-Soriano V, Burlet N, Vela D, Fontdevila A, Vieira C, García Guerreiro MP. Drosophila Females Undergo Genome Expansion after Interspecific Hybridization. Genome Biol Evol 2016; 8:556-61. [PMID: 26872773 PMCID: PMC4824032 DOI: 10.1093/gbe/evw024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Genome size (or C-value) can present a wide range of values among eukaryotes. This variation has been attributed to differences in the amplification and deletion of different noncoding repetitive sequences, particularly transposable elements (TEs). TEs can be activated under different stress conditions such as interspecific hybridization events, as described for several species of animals and plants. These massive transposition episodes can lead to considerable genome expansions that could ultimately be involved in hybrid speciation processes. Here, we describe the effects of hybridization and introgression on genome size of Drosophila hybrids. We measured the genome size of two close Drosophila species, Drosophila buzzatii and Drosophila koepferae, their F1 offspring and the offspring from three generations of backcrossed hybrids; where mobilization of up to 28 different TEs was previously detected. We show that hybrid females indeed present a genome expansion, especially in the first backcross, which could likely be explained by transposition events. Hybrid males, which exhibit more variable C-values among individuals of the same generation, do not present an increased genome size. Thus, we demonstrate that the impact of hybridization on genome size can be detected through flow cytometry and is sex-dependent.
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Affiliation(s)
- Valèria Romero-Soriano
- Departament De Genètica I Microbiologia (Edifici C), Grup De Genòmica, Bioinformàtica I Biologia Evolutiva. Universitat Autònoma De Barcelona, Spain
| | - Nelly Burlet
- Laboratoire De Biométrie Et Biologie Evolutive, UMR5558, Université Lyon 1, Université Lyon, Villeurbanne, France
| | - Doris Vela
- Laboratorio De Genética Evolutiva, Pontificia Universidad Católica Del Ecuador, Quito, Ecuador
| | - Antonio Fontdevila
- Departament De Genètica I Microbiologia (Edifici C), Grup De Genòmica, Bioinformàtica I Biologia Evolutiva. Universitat Autònoma De Barcelona, Spain
| | - Cristina Vieira
- Laboratoire De Biométrie Et Biologie Evolutive, UMR5558, Université Lyon 1, Université Lyon, Villeurbanne, France
| | - María Pilar García Guerreiro
- Departament De Genètica I Microbiologia (Edifici C), Grup De Genòmica, Bioinformàtica I Biologia Evolutiva. Universitat Autònoma De Barcelona, Spain
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Global transcriptional and miRNA insights into bases of heterosis in hybridization of Cyprinidae. Sci Rep 2015; 5:13847. [PMID: 26346824 PMCID: PMC4561955 DOI: 10.1038/srep13847] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/07/2015] [Indexed: 01/06/2023] Open
Abstract
Hybrid Megalobrama amblycephala × Culter alburnus represents a population newly formed by interspecific crossing between two different genera. Here we assessed the expression pattern of mRNA and small RNA in newly formed F1, F2 and their progenitors. Large amounts of nonadditively expressed protein-coding genes showed parental expression level dominance (ELD). Interestingly, the ELD pattern could inherit from F1 to F2, which guaranteed a stable appearance in progenies. The ELD-B genes were found to contribute to cell development, while the ELD-T genes were enriched in function of stress and adaptability. microRNAs (miRNA) also had similar expression patterns to genes. A high proportion of miRNAs showed nonadditive expression upon hybridization, and were found to target important genes with diverse roles potentially involved in stress adaption and development. Taken together, the gene and miRNA expression divergence contributes to heterosis in the newly formed hybrid, promising the successful existence of hybrid speciation.
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33
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Renaut S, Rowe HC, Ungerer MC, Rieseberg LH. Genomics of homoploid hybrid speciation: diversity and transcriptional activity of long terminal repeat retrotransposons in hybrid sunflowers. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0345. [PMID: 24958919 DOI: 10.1098/rstb.2013.0345] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hybridization is thought to play an important role in plant evolution by introducing novel genetic combinations and promoting genome restructuring. However, surprisingly little is known about the impact of hybridization on transposable element (TE) proliferation and the genomic response to TE activity. In this paper, we first review the mechanisms by which homoploid hybrid species may arise in nature. We then present hybrid sunflowers as a case study to examine transcriptional activity of long terminal repeat retrotransposons in the annual sunflowers Helianthus annuus, Helianthus petiolaris and their homoploid hybrid derivatives (H. paradoxus, H. anomalus and H. deserticola) using high-throughput transcriptome sequencing technologies (RNAseq). Sampling homoploid hybrid sunflower taxa revealed abundant variation in TE transcript accumulation. In addition, genetic diversity for several candidate genes hypothesized to regulate TE activity was characterized. Specifically, we highlight one candidate chromatin remodelling factor gene with a direct role in repressing TE activity in a hybrid species. This paper shows that TE amplification in hybrid lineages is more idiosyncratic than previously believed and provides a first step towards identifying the mechanisms responsible for regulating and repressing TE expansions.
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Affiliation(s)
- Sebastien Renaut
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Heather C Rowe
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Mark C Ungerer
- Division of Biology, Kansas State University, 426 Ackert Hall, Manhattan, KS 66506, USA
| | - Loren H Rieseberg
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 Department of Biology, Indiana University, 1001 East Third St., Bloomington, IN 47405, USA
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Lafon-Placette C, Köhler C. Epigenetic mechanisms of postzygotic reproductive isolation in plants. CURRENT OPINION IN PLANT BIOLOGY 2015; 23:39-44. [PMID: 25449725 DOI: 10.1016/j.pbi.2014.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/10/2014] [Accepted: 10/16/2014] [Indexed: 05/25/2023]
Abstract
Hybrid incompatibility is generally viewed as a consequence of negative epistatic interactions between alleles that do not cause negative fitness effects in their parents. Substantial evidence in support of the model has accumulated over recent years. Nevertheless, there is evidence that hybrid incompatibility can have an epigenetic basis and results from deregulated small RNAs (sRNAs), causing changes in DNA methylation and transposable element (TE) activation. Epigenetically regulated loci can impact on the expression of nearby located genes. Alteration of dosage-sensitive gene expression builds hybridization barriers in the endosperm; however, it may also offer an explanation for transgressive effects in plant hybrids. In this review we highlight recent advances that illuminate the role of epigenetic pathways in establishing hybrid incompatibility in plants.
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Affiliation(s)
- Clément Lafon-Placette
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, 750 07 Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, 750 07 Uppsala, Sweden.
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35
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Belyayev A. Bursts of transposable elements as an evolutionary driving force. J Evol Biol 2014; 27:2573-84. [PMID: 25290698 DOI: 10.1111/jeb.12513] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 12/25/2022]
Abstract
A burst of transposable elements (TEs) is a massive outbreak that may cause radical genomic rebuilding. This phenomenon has been reported in connection with the formation of taxonomic groups and species and has therefore been associated with major evolutionary events in the past. Over the past few years, several research groups have discovered recent stress-induced bursts of different TEs. The events for which bursts of TEs have been recorded include domestication, polyploidy, changes in mating systems, interspecific and intergeneric hybridization and abiotic stress. Cases involving abiotic stress, particularly bursts of TEs in natural populations driven by environmental change, are of special interest because this phenomenon may underlie micro- and macro-evolutionary events and ultimately support the maintenance and generation of biological diversity. This study reviews the known cases of bursts of TEs and their possible consequences, with particular emphasis on the speciation process.
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Affiliation(s)
- A Belyayev
- Institute of Botany, Czech Academy of Sciences, Pruhonice near Prague, Czech Republic
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36
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Guerreiro MPG. Interspecific hybridization as a genomic stressor inducing mobilization of transposable elements in Drosophila.. Mob Genet Elements 2014; 4:e34394. [PMID: 25136509 PMCID: PMC4132227 DOI: 10.4161/mge.34394] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/07/2014] [Accepted: 08/08/2014] [Indexed: 11/26/2022] Open
Abstract
Transposable elements (TEs) are DNA sequences able to be mobilized in host genomes. They are currently recognized as the major mutation inducers because of their insertion in the target, their effect on neighboring regions, or their ectopic recombination. A large number of factors including chemical and physical factors as well as intraspecific crosses have traditionally been identified as inducers of transposition. Besides environmental factors, interspecific crosses have also been proposed as promoters of transposition of particular TEs in plants and different animals. Our previous published work includes a genome-wide survey with the set of genomic TEs and shows that interspecific hybridization between the species Drosophila buzzatii and Drosophila koepferae induces genomic instability by transposition bursts. A high percentage of this instability corresponds to TEs belonging to classes I and II. The detailed study of three TEs (Osvaldo, Helena, and Galileo), representative of the different TE families, shows an increase of transposition in hybrids compared with parental species, that varies depending on the element. This study suggests ample variation in TE regulation mechanisms and the question is why this variation occurs. Interspecific hybridization is a genomic stressor that disrupts the stability of TEs probably contributing to a relaxation of the mechanisms controlling TEs in the Drosophila genome. In this commentary paper we will discuss these results and the molecular mechanisms that could explain these increases of transposition rates observed in interspecific Drosophila hybrids.
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Affiliation(s)
- Maria Pilar García Guerreiro
- Grup de Biologia Evolutiva; Departament de Genètica i Microbiologia; Facultat de Biociències; Universitat Autònoma de Barcelona; Barcelona, Spain
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37
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Endogenously imprinted genes in Drosophila melanogaster. Mol Genet Genomics 2014; 289:653-73. [DOI: 10.1007/s00438-014-0840-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 03/04/2014] [Indexed: 12/21/2022]
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38
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Dion-Côté AM, Renaut S, Normandeau E, Bernatchez L. RNA-seq Reveals Transcriptomic Shock Involving Transposable Elements Reactivation in Hybrids of Young Lake Whitefish Species. Mol Biol Evol 2014; 31:1188-99. [DOI: 10.1093/molbev/msu069] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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39
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Inheritance of Trans Chromosomal Methylation patterns from Arabidopsis F1 hybrids. Proc Natl Acad Sci U S A 2014; 111:2017-22. [PMID: 24449910 DOI: 10.1073/pnas.1323656111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hybridization in plants leads to transinteractions between the parental genomes and epigenomes that can result in changes to both 24 nt siRNA and cytosine methylation ((m)C) levels in the hybrid. In Arabidopsis the principle processes altering the hybrid methylome are Trans Chromosomal Methylation (TCM) and Trans Chromosomal deMethylation (TCdM) in which the (m)C pattern of a genomic segment attains the same (m)C pattern of the corresponding segment on the other parental chromosome. We examined two loci that undergo TCM/TCdM in the Arabidopsis C24/Landsberg erecta (Ler) F1 hybrids, which show patterns of inheritance dependent on the properties of the particular donor and recipient chromosomal segments. At At1g64790 the TCM- and TCdM-derived (m)C patterns are maintained in the F2 generation but are transmitted in outcrosses or backcrosses only by the C24 genomic segment. At a region between and adjacent to At3g43340 and At3g43350, the originally unmethylated Ler genomic segment receives the C24 (m)C pattern in the F1, which is then maintained in backcross plants independent of the presence of the parental C24 segment. In backcrosses to an unmethylated Ler allele, the newly methylated F1 Ler segment may act as a TCM source in a process comparable to paramutation in maize. TCM-derived (m)C patterns are associated with reduced expression of both At3g43340 and At3g43350 in F1 and F2 plants, providing support for such events influencing the transcriptome. The inheritance of the F1 (m)C patterns and the segregation of other genetic and epigenetic determinants may contribute to the reduced hybrid vigor in the F2 and subsequent generations.
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40
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Parisod C, Salmon A, Ainouche M, Grandbastien MA. Detecting epigenetic effects of transposable elements in plants. Methods Mol Biol 2014; 1112:211-217. [PMID: 24478017 DOI: 10.1007/978-1-62703-773-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Transposable elements (TE) represent a major fraction of eukaryotic genomes and play many roles in plant epigenetics. In this chapter, we describe the use of Sequence-Specific Amplified Polymorphism (SSAP) as a reliable Transposon Display technique applicable for use in many plant species. We also discuss the interpretation of SSAP data and associated risks. This technique has potential to allow rapid screening of plant populations, especially in nonmodel or wild species.
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Affiliation(s)
- Christian Parisod
- Laboratory of Evolutionary Botany, Biology Institute, University of Neuchâtel, Neuchâtel, Switzerland
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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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Akbari OS, Antoshechkin I, Hay BA, Ferree PM. Transcriptome profiling of Nasonia vitripennis testis reveals novel transcripts expressed from the selfish B chromosome, paternal sex ratio. G3 (BETHESDA, MD.) 2013; 3:1597-605. [PMID: 23893741 PMCID: PMC3755920 DOI: 10.1534/g3.113.007583] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/16/2013] [Indexed: 11/18/2022]
Abstract
A widespread phenomenon in nature is sex ratio distortion of arthropod populations caused by microbial and genetic parasites. Currently little is known about how these agents alter host developmental processes to favor one sex or the other. The paternal sex ratio (PSR) chromosome is a nonessential, paternally transmitted centric fragment that segregates in natural populations of the jewel wasp, Nasonia vitripennis. To persist, PSR is thought to modify the hereditary material of the developing sperm, with the result that all nuclear DNA other than the PSR chromosome is destroyed shortly after fertilization. This results in the conversion of a fertilized embryo--normally a female--into a male, thereby insuring transmission of the "selfish" PSR chromosome, and simultaneously leading to wasp populations that are male-biased. To begin to understand this system at the mechanistic level, we carried out transcriptional profiling of testis from WT and PSR-carrying males. We identified a number of transcripts that are differentially expressed between these conditions. We also discovered nine transcripts that are uniquely expressed from the PSR chromosome. Four of these PSR-specific transcripts encode putative proteins, whereas the others have very short open reading frames and no homology to known proteins, suggesting that they are long noncoding RNAs. We propose several different models for how these transcripts could facilitate PSR-dependent effects. Our analyses also revealed 15.71 MB of novel transcribed regions in the N. vitripennis genome, thus increasing the current annotation of total transcribed regions by 53.4%. Finally, we detected expression of multiple meiosis-related genes in the wasp testis, despite the lack of conventional meiosis in the male sex.
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Affiliation(s)
- Omar S. Akbari
- Division of Biology, MC156-29, California Institute of Technology, Pasadena, California 91125
| | - Igor Antoshechkin
- Division of Biology, MC156-29, California Institute of Technology, Pasadena, California 91125
| | - Bruce A. Hay
- Division of Biology, MC156-29, California Institute of Technology, Pasadena, California 91125
| | - Patrick M. Ferree
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California 91711
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The role of epigenetics in hybrid vigour. Trends Genet 2013; 29:684-90. [PMID: 23953922 DOI: 10.1016/j.tig.2013.07.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/04/2013] [Accepted: 07/22/2013] [Indexed: 12/23/2022]
Abstract
Hybrid vigour, or heterosis, refers to the increased yield and biomass of hybrid offspring relative to the parents. Although this has been exploited in plants for agriculture and horticulture, the molecular and cellular mechanisms underlying hybrid vigour are largely unknown. Genetic analyses show that there are a large number of quantitative trait loci (QTLs) that contribute to the heterotic phenotype, indicating that it is a complex phenomenon. Gene expression in hybrids is regulated by the interactions of the two parental epigenetic systems and the underlying genomes. Increasing understanding of the interplay of small RNA (sRNA) molecules, DNA methylation, and histone marks provides new opportunities to define the basis of hybrid vigour and to understand why F1 heterosis is not passed on to subsequent generations. We discuss recent findings that suggest the existence of several pathways that alter DNA methylation patterns, which may lead to transcriptional changes resulting in the heterotic phenotype.
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Arkhipova IR, Rodriguez F. Genetic and epigenetic changes involving (retro)transposons in animal hybrids and polyploids. Cytogenet Genome Res 2013; 140:295-311. [PMID: 23899811 DOI: 10.1159/000352069] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Transposable elements (TEs) are discrete genetic units that have the ability to change their location within chromosomal DNA, and constitute a major and rapidly evolving component of eukaryotic genomes. They can be subdivided into 2 distinct types: retrotransposons, which use an RNA intermediate for transposition, and DNA transposons, which move only as DNA. Rapid advances in genome sequencing significantly improved our understanding of TE roles in genome shaping and restructuring, and studies of transcriptomes and epigenomes shed light on the previously unknown molecular mechanisms underlying genetic and epigenetic TE controls. Knowledge of these control systems may be important for better understanding of reticulate evolution and speciation in the context of bringing different genomes together by hybridization and perturbing the established regulatory balance by ploidy changes. See also sister article focusing on plants by Bento et al. in this themed issue.
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Affiliation(s)
- I R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA. iarkhipova @ mbl.edu
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Shapiro JA. How life changes itself: the Read-Write (RW) genome. Phys Life Rev 2013; 10:287-323. [PMID: 23876611 DOI: 10.1016/j.plrev.2013.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 07/02/2013] [Indexed: 01/06/2023]
Abstract
The genome has traditionally been treated as a Read-Only Memory (ROM) subject to change by copying errors and accidents. In this review, I propose that we need to change that perspective and understand the genome as an intricately formatted Read-Write (RW) data storage system constantly subject to cellular modifications and inscriptions. Cells operate under changing conditions and are continually modifying themselves by genome inscriptions. These inscriptions occur over three distinct time-scales (cell reproduction, multicellular development and evolutionary change) and involve a variety of different processes at each time scale (forming nucleoprotein complexes, epigenetic formatting and changes in DNA sequence structure). Research dating back to the 1930s has shown that genetic change is the result of cell-mediated processes, not simply accidents or damage to the DNA. This cell-active view of genome change applies to all scales of DNA sequence variation, from point mutations to large-scale genome rearrangements and whole genome duplications (WGDs). This conceptual change to active cell inscriptions controlling RW genome functions has profound implications for all areas of the life sciences.
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Affiliation(s)
- James A Shapiro
- Dept. of Biochemistry and Molecular Biology, University of Chicago, GCIS W123B, 979 E. 57th Street, Chicago, IL 60637, USA. http://www.huffingtonpost.com/james-a-shapiro
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Ashman TL, Kwok A, Husband BC. Revisiting the dioecy-polyploidy association: alternate pathways and research opportunities. Cytogenet Genome Res 2013; 140:241-55. [PMID: 23838528 DOI: 10.1159/000353306] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The evolutionary transition from hermaphroditism (combined sexes) to dioecy (separate sexes) is associated with whole genome duplication (polyploidy) in several flowering plant genera. Moreover, there is evidence for transitions in the opposite direction, i.e. a loss of dioecy with an increase in ploidy. Here, we review evidence for these associations, synthesize previous ideas on the mechanism underlying the patterns and explore alternative pathways. Specifically, we examine potential ecological and genetic mechanisms, differentiated by whether ploidy or gender (functional sex expression of the plant) changes are the primary cause and whether the effect is direct or indirect. An analysis of 22 genera variable for both ploidy and gender indicates that gender monomorphism (hermaphroditism, monoecy) is more common among diploid than polyploid species, whereas gender dimorphism (dioecy, gynodioecy, subdioecy) is more frequent among polyploid species. The transition from diploid hermaphroditic to polyploid gender-dimorphic taxa may arise directly through changes in gender as a result of genome duplication through genomic rearrangements or homeologous recombination, or changes in gender may result in increased unreduced gamete production leading to polyploid formation. Alternatively, the transition may occur through the indirect effects of genome duplication on mating system and inbreeding depression, which favor selection for unisexuality, or habitat shifts associated with unisexuality may simultaneously cause increased unreduced gamete production. Novel mechanisms for transitions in the opposite direction (from dioecy to hermaphroditism with increase in ploidy) include disruption of genetic sex determination and the benefits of reproductive assurance. We highlight key questions requiring further attention and promising approaches for answering them and better clarifying the genesis of sexual system polyploidy associations. See also the sister article focusing on animals by Wertheim et al. in this themed issue.
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Affiliation(s)
- T-L Ashman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260-3929, USA. tia1 @ pitt.edu
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Nagel JH, Gryzenhout M, Slippers B, Wingfield MJ, Hardy GE, Stukely MJ, Burgess TI. Characterization of Phytophthora hybrids from ITS clade 6 associated with riparian ecosystems in South Africa and Australia. Fungal Biol 2013; 117:329-47. [DOI: 10.1016/j.funbio.2013.03.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 03/15/2013] [Accepted: 03/19/2013] [Indexed: 11/30/2022]
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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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Abbott R, Albach D, Ansell S, Arntzen JW, Baird SJE, Bierne N, Boughman J, Brelsford A, Buerkle CA, Buggs R, Butlin RK, Dieckmann U, Eroukhmanoff F, Grill A, Cahan SH, Hermansen JS, Hewitt G, Hudson AG, Jiggins C, Jones J, Keller B, Marczewski T, Mallet J, Martinez-Rodriguez P, Möst M, Mullen S, Nichols R, Nolte AW, Parisod C, Pfennig K, Rice AM, Ritchie MG, Seifert B, Smadja CM, Stelkens R, Szymura JM, Väinölä R, Wolf JBW, Zinner D. Hybridization and speciation. J Evol Biol 2013; 26:229-46. [DOI: 10.1111/j.1420-9101.2012.02599.x] [Citation(s) in RCA: 1370] [Impact Index Per Article: 124.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/25/2012] [Accepted: 07/16/2012] [Indexed: 12/17/2022]
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