1
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Le Veve A, Genete M, Lepers-Blassiau C, Ponitzki C, Poux C, Vekemans X, Durand E, Castric V. The genetic architecture of the load linked to dominant and recessive self-incompatibility alleles in Arabidopsis halleri and Arabidopsis lyrata. eLife 2024; 13:RP94972. [PMID: 39222005 PMCID: PMC11368402 DOI: 10.7554/elife.94972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
The long-term balancing selection acting on mating types or sex-determining genes is expected to lead to the accumulation of deleterious mutations in the tightly linked chromosomal segments that are locally 'sheltered' from purifying selection. However, the factors determining the extent of this accumulation are poorly understood. Here, we took advantage of variations in the intensity of balancing selection along a dominance hierarchy formed by alleles at the sporophytic self-incompatibility system of the Brassicaceae to compare the pace at which linked deleterious mutations accumulate among them. We first experimentally measured the phenotypic manifestation of the linked load at three different levels of the dominance hierarchy. We then sequenced and phased polymorphisms in the chromosomal regions linked to 126 distinct copies of S-alleles in two populations of Arabidopsis halleri and three populations of Arabidopsis lyrata. We find that linkage to the S-locus locally distorts phylogenies over about 10-30 kb along the chromosome. The more intense balancing selection on dominant S-alleles results in greater fixation of linked deleterious mutations, while recessive S-alleles accumulate more linked deleterious mutations that are segregating. Hence, the structure rather than the overall magnitude of the linked genetic load differs between dominant and recessive S-alleles. Our results have consequences for the long-term evolution of new S-alleles, the evolution of dominance modifiers between them, and raise the question of why the non-recombining regions of some sex and mating type chromosomes expand over evolutionary times while others, such as the S-locus of the Brassicaceae, remain restricted to small chromosomal regions.
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Affiliation(s)
| | | | | | | | - Céline Poux
- Univ. Lille, CNRS, UMR 8198 – Evo-Eco-PaleoLilleFrance
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2
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Augustijnen H, Bätscher L, Cesanek M, Chkhartishvili T, Dincă V, Iankoshvili G, Ogawa K, Vila R, Klopfstein S, de Vos JM, Lucek K. A macroevolutionary role for chromosomal fusion and fission in Erebia butterflies. SCIENCE ADVANCES 2024; 10:eadl0989. [PMID: 38630820 PMCID: PMC11023530 DOI: 10.1126/sciadv.adl0989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
The impact of large-scale chromosomal rearrangements, such as fusions and fissions, on speciation is a long-standing conundrum. We assessed whether bursts of change in chromosome numbers resulting from chromosomal fusion or fission are related to increased speciation rates in Erebia, one of the most species-rich and karyotypically variable butterfly groups. We established a genome-based phylogeny and used state-dependent birth-death models to infer trajectories of karyotype evolution. We demonstrated that rates of anagenetic chromosomal changes (i.e., along phylogenetic branches) exceed cladogenetic changes (i.e., at speciation events), but, when cladogenetic changes occur, they are mostly associated with chromosomal fissions rather than fusions. We found that the relative importance of fusion and fission differs among Erebia clades of different ages and that especially in younger, more karyotypically diverse clades, speciation is more frequently associated with cladogenetic chromosomal changes. Overall, our results imply that chromosomal fusions and fissions have contrasting macroevolutionary roles and that large-scale chromosomal rearrangements are associated with bursts of species diversification.
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Affiliation(s)
- Hannah Augustijnen
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Livio Bätscher
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Martin Cesanek
- Slovak Entomological Society, Slovak Academy of Sciences, Bratislava 1, Slovakia
| | | | - Vlad Dincă
- Ecology and Genetics Research Unit, University of Oulu, 90570 Oulu, Finland
| | | | - Kota Ogawa
- Faculty of Social and Cultural Studies, Kyushu University, Fukuoka 819-0395, Japan
- Insect Sciences and Creative Entomology Center, Kyushu University, Fukuoka 819-0395, Japan
| | - Roger Vila
- Institut de Biologia Evolutiva (CSIC-Univ. Pompeu Fabra), 08003 Barcelona, Spain
| | - Seraina Klopfstein
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Life Sciences, Natural History Museum Basel, 4051 Basel, Switzerland
| | - Jurriaan M. de Vos
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Kay Lucek
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
- Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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3
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Xiong J, He Z, Wang L, Fan C, Chao J. DNA Origami-Enabled Gene Localization of Repetitive Sequences. J Am Chem Soc 2024; 146:6317-6325. [PMID: 38391280 DOI: 10.1021/jacs.4c00039] [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: 02/24/2024]
Abstract
Repetitive sequences, which make up over 50% of human DNA, have diverse applications in disease diagnosis, forensic identification, paternity testing, and population genetic analysis due to their crucial functions for gene regulation. However, representative detection technologies such as sequencing and fluorescence imaging suffer from time-consuming protocols, high cost, and inaccuracy of the position and order of repetitive sequences. Here, we develop a precise and cost-effective strategy that combines the high resolution of atomic force microscopy with the shape customizability of DNA origami for repetitive sequence-specific gene localization. "Tri-block" DNA structures were specifically designed to connect repetitive sequences to DNA origami tags, thereby revealing precise genetic information in terms of position and sequence for high-resolution and high-precision visualization of repetitive sequences. More importantly, we achieved the results of simultaneous detection of different DNA repetitive sequences on the gene template with a resolution of ∼6.5 nm (19 nt). This strategy is characterized by high efficiency, high precision, low operational complexity, and low labor/time costs, providing a powerful complement to sequencing technologies for gene localization of repetitive sequences.
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Affiliation(s)
- Jinxin Xiong
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
| | - Zhimei He
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
| | - Lianhui Wang
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, New Cornerstone Science Laboratory, Frontiers Science Center for Transformative Molecules, Zhangjiang Institute for Advanced Study and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acids Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Jie Chao
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
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4
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Kolesnikova UK, Scott AD, Van de Velde JD, Burns R, Tikhomirov NP, Pfordt U, Clarke AC, Yant L, Seregin AP, Vekemans X, Laurent S, Novikova PY. Transition to Self-compatibility Associated With Dominant S-allele in a Diploid Siberian Progenitor of Allotetraploid Arabidopsis kamchatica Revealed by Arabidopsis lyrata Genomes. Mol Biol Evol 2023; 40:msad122. [PMID: 37432770 PMCID: PMC10335350 DOI: 10.1093/molbev/msad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
A transition to selfing can be beneficial when mating partners are scarce, for example, due to ploidy changes or at species range edges. Here, we explain how self-compatibility evolved in diploid Siberian Arabidopsis lyrata, and how it contributed to the establishment of allotetraploid Arabidopsis kamchatica. First, we provide chromosome-level genome assemblies for two self-fertilizing diploid A. lyrata accessions, one from North America and one from Siberia, including a fully assembled S-locus for the latter. We then propose a sequence of events leading to the loss of self-incompatibility in Siberian A. lyrata, date this independent transition to ∼90 Kya, and infer evolutionary relationships between Siberian and North American A. lyrata, showing an independent transition to selfing in Siberia. Finally, we provide evidence that this selfing Siberian A. lyrata lineage contributed to the formation of the allotetraploid A. kamchatica and propose that the selfing of the latter is mediated by the loss-of-function mutation in a dominant S-allele inherited from A. lyrata.
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Affiliation(s)
- Uliana K Kolesnikova
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Alison Dawn Scott
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Jozefien D Van de Velde
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Robin Burns
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Nikita P Tikhomirov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
- Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
| | - Ursula Pfordt
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Andrew C Clarke
- Future Food Beacon of Excellence and School of Biosciences, University of Nottingham, Sutton Bonington, United Kingdom
| | - Levi Yant
- Future Food Beacon of Excellence and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alexey P Seregin
- Herbarium (MW), Faculty of Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Xavier Vekemans
- University Lille, CNRS, UMR 8198—Evo-Eco-Paleo, Lille, France
| | - Stefan Laurent
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Polina Yu Novikova
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
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5
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Novikova PY, Kolesnikova UK, Scott AD. Ancestral self-compatibility facilitates the establishment of allopolyploids in Brassicaceae. PLANT REPRODUCTION 2023; 36:125-138. [PMID: 36282331 PMCID: PMC9957919 DOI: 10.1007/s00497-022-00451-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/20/2022] [Indexed: 05/15/2023]
Abstract
Self-incompatibility systems based on self-recognition evolved in hermaphroditic plants to maintain genetic variation of offspring and mitigate inbreeding depression. Despite these benefits in diploid plants, for polyploids who often face a scarcity of mating partners, self-incompatibility can thwart reproduction. In contrast, self-compatibility provides an immediate advantage: a route to reproductive viability. Thus, diploid selfing lineages may facilitate the formation of new allopolyploid species. Here, we describe the mechanism of establishment of at least four allopolyploid species in Brassicaceae (Arabidopsis suecica, Arabidopsis kamchatica, Capsella bursa-pastoris, and Brassica napus), in a manner dependent on the prior loss of the self-incompatibility mechanism in one of the ancestors. In each case, the degraded S-locus from one parental lineage was dominant over the functional S-locus of the outcrossing parental lineage. Such dominant loss-of-function mutations promote an immediate transition to selfing in allopolyploids and may facilitate their establishment.
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Affiliation(s)
- Polina Yu Novikova
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, 50829, Cologne, Germany.
| | - Uliana K Kolesnikova
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, 50829, Cologne, Germany
| | - Alison Dawn Scott
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, 50829, Cologne, Germany
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6
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Hedhly A, Guerra ME, Grimplet J, Rodrigo J. S-Locus Genotyping in Japanese Plum by High Throughput Sequencing Using a Synthetic S-Loci Reference Sequence. Int J Mol Sci 2023; 24:3932. [PMID: 36835346 PMCID: PMC9960950 DOI: 10.3390/ijms24043932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023] Open
Abstract
Self-incompatibility in Prunus species is governed by a single locus consisting of two highly multi-allelic and tightly linked genes, one coding for an F-box protein-i.e., SFB in Prunus- controlling the pollen specificity and one coding for an S-RNase gene controlling the pistil specificity. Genotyping the allelic combination in a fruit tree species is an essential procedure both for cross-based breeding and for establishing pollination requirements. Gel-based PCR techniques using primer pairs designed from conserved regions and spanning polymorphic intronic regions are traditionally used for this task. However, with the great advance of massive sequencing techniques and the lowering of sequencing costs, new genotyping-by-sequencing procedures are emerging. The alignment of resequenced individuals to reference genomes, commonly used for polymorphism detection, yields little or no coverage in the S-locus region due to high polymorphism between different alleles within the same species, and cannot be used for this purpose. Using the available sequences of Japanese plum S-loci concatenated in a rosary-like structure as synthetic reference sequence, we describe a procedure to accurately genotype resequenced individuals that allowed the analysis of the S-genotype in 88 Japanese plum cultivars, 74 of them are reported for the first time. In addition to unraveling two new S-alleles from published reference genomes, we identified at least two S-alleles in 74 cultivars. According to their S-allele composition, they were assigned to 22 incompatibility groups, including nine new incompatibility groups reported here for the first time (XXVII-XXXV).
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Affiliation(s)
- Afif Hedhly
- Departamento de Ciencia Vegetal, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Avda Montañana 930, 50059 Zaragoza, Spain
| | - María Engracia Guerra
- Área de Fruticultura Mediterránea, CICYTEX-Centro de Investigación ‘Finca La Orden-Valdesequera’, A-V, KM 372, Guadajira, 06187 Badajoz, Spain
| | - Jerome Grimplet
- Departamento de Ciencia Vegetal, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Avda Montañana 930, 50059 Zaragoza, Spain
- Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, 50013 Zaragoza, Spain
| | - Javier Rodrigo
- Departamento de Ciencia Vegetal, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Avda Montañana 930, 50059 Zaragoza, Spain
- Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, 50013 Zaragoza, Spain
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7
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Recent speciation associated with range expansion and a shift to self-fertilization in North American Arabidopsis. Nat Commun 2022; 13:7564. [PMID: 36481740 PMCID: PMC9732334 DOI: 10.1038/s41467-022-35368-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
The main processes classically evoked for promoting reproductive isolation and speciation are geographic separation reducing gene flow among populations, divergent selection, and chance genomic change. In a case study, we present evidence that the additional factors of climate change, range expansion and a shift in mating towards inbreeding can initiate the processes leading to parapatric speciation. At the end of the last Pleistocene glaciation cycle, the North American plant Arabidopsis lyrata expanded its range and concomitantly lost its reproductive mode of outcrossing multiple times. We show that in one of the newly colonized areas, the self-fertilizing recolonization lineage of A. lyrata gave rise to selfing A. arenicola, which expanded its range to subarctic and arctic Canada and Greenland, while the parental species remained restricted to temperate North America. Despite the vast range expansion by the new species, mutational load did not increase, probably because of selfing and quasi-clonal selection. We conclude that such peripheral parapatric speciation combined with range expansion and inbreeding may be an important but so far overlooked mode of speciation.
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8
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Vekemans X, Castric V. When the genetic architecture matters: evolutionary and ecological implications of self versus nonself recognition in plant self-incompatibility. THE NEW PHYTOLOGIST 2021; 231:1304-1307. [PMID: 34146416 DOI: 10.1111/nph.17471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Xavier Vekemans
- CNRS, Univ. Lille, UMR 8198 - Evo-Eco-Paleo, Lille, F-59000, France
| | - Vincent Castric
- CNRS, Univ. Lille, UMR 8198 - Evo-Eco-Paleo, Lille, F-59000, France
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9
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Vekemans X, Castric V, Hipperson H, Müller NA, Westerdahl H, Cronk Q. Whole-genome sequencing and genome regions of special interest: Lessons from major histocompatibility complex, sex determination, and plant self-incompatibility. Mol Ecol 2021; 30:6072-6086. [PMID: 34137092 PMCID: PMC9290700 DOI: 10.1111/mec.16020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 05/31/2021] [Accepted: 06/07/2021] [Indexed: 11/27/2022]
Abstract
Whole‐genome sequencing of non‐model organisms is now widely accessible and has allowed a range of questions in the field of molecular ecology to be investigated with greater power. However, some genomic regions that are of high biological interest remain problematic for assembly and data‐handling. Three such regions are the major histocompatibility complex (MHC), sex‐determining regions (SDRs) and the plant self‐incompatibility locus (S‐locus). Using these as examples, we illustrate the challenges of both assembling and resequencing these highly polymorphic regions and how bioinformatic and technological developments are enabling new approaches to their study. Mapping short‐read sequences against multiple alternative references improves genotyping comprehensiveness at the S‐locus thereby contributing to more accurate assessments of allelic frequencies. Long‐read sequencing, producing reads of several tens to hundreds of kilobase pairs in length, facilitates the assembly of such regions as single sequences can span the multiple duplicated gene copies of the MHC region, and sequence through repetitive stretches and translocations in SDRs and S‐locus haplotypes. These advances are adding value to short‐read genome resequencing approaches by allowing, for example, more accurate haplotype phasing across longer regions. Finally, we assessed further technical improvements, such as nanopore adaptive sequencing and bioinformatic tools using pangenomes, which have the potential to further expand our knowledge of a number of genomic regions that remain challenging to study with classical resequencing approaches.
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Affiliation(s)
| | | | - Helen Hipperson
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Niels A Müller
- Thünen Institute of Forest Genetics, Grosshansdorf, Germany
| | - Helena Westerdahl
- Molecular Ecology and Evolution Laboratory, Department of Biology, Lund University, Lund, Sweden
| | - Quentin Cronk
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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10
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Tonnabel J, David P, Janicke T, Lehner A, Mollet JC, Pannell JR, Dufay M. The Scope for Postmating Sexual Selection in Plants. Trends Ecol Evol 2021; 36:556-567. [PMID: 33775429 DOI: 10.1016/j.tree.2021.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 11/27/2022]
Abstract
Sexual selection is known to shape plant traits that affect access to mates during the pollination phase, but it is less well understood to what extent it affects traits relevant to interactions between pollen and pistils after pollination. This is surprising, because both of the two key modes of sexual selection, male-male competition and female choice, could plausibly operate during pollen-pistil interactions where physical male-female contact occurs. Here, we consider how the key processes of sexual selection might affect traits involved in pollen-pistil interactions, including 'Fisherian runaway' and 'good-genes' models. We review aspects of the molecular and cellular biology of pollen-pistil interactions on which sexual selection could act and point to research that is needed to investigate them.
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Affiliation(s)
- Jeanne Tonnabel
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France.
| | - Patrice David
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Tim Janicke
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France; Applied Zoology, Technical University Dresden, Zellescher Weg 20b, 01062 Dresden, Germany
| | - Arnaud Lehner
- Normandie Univ, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (GlycoMEV), SFR 4377 NORVEGE, IRIB, Carnot I2C, 76000 Rouen, France
| | - Jean-Claude Mollet
- Normandie Univ, UNIROUEN, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (GlycoMEV), SFR 4377 NORVEGE, IRIB, Carnot I2C, 76000 Rouen, France
| | - John R Pannell
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Mathilde Dufay
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
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11
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Takou M, Hämälä T, Koch EM, Steige KA, Dittberner H, Yant L, Genete M, Sunyaev S, Castric V, Vekemans X, Savolainen O, de Meaux J. Maintenance of Adaptive Dynamics and No Detectable Load in a Range-Edge Outcrossing Plant Population. Mol Biol Evol 2021; 38:1820-1836. [PMID: 33480994 PMCID: PMC8097302 DOI: 10.1093/molbev/msaa322] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
During range expansion, edge populations are expected to face increased genetic drift, which in turn can alter and potentially compromise adaptive dynamics, preventing the removal of deleterious mutations and slowing down adaptation. Here, we contrast populations of the European subspecies Arabidopsis lyrata ssp. petraea, which expanded its Northern range after the last glaciation. We document a sharp decline in effective population size in the range-edge population and observe that nonsynonymous variants segregate at higher frequencies. We detect a 4.9% excess of derived nonsynonymous variants per individual in the range-edge population, suggesting an increase of the genomic burden of deleterious mutations. Inference of the fitness effects of mutations and modeling of allele frequencies under the explicit demographic history of each population predicts a depletion of rare deleterious variants in the range-edge population, but an enrichment for fixed ones, consistent with the bottleneck effect. However, the demographic history of the range-edge population predicts a small net decrease in per-individual fitness. Consistent with this prediction, the range-edge population is not impaired in its growth and survival measured in a common garden experiment. We further observe that the allelic diversity at the self-incompatibility locus, which ensures strict outcrossing and evolves under negative frequency-dependent selection, has remained unchanged. Genomic footprints indicative of selective sweeps are broader in the Northern population but not less frequent. We conclude that the outcrossing species A. lyrata ssp. petraea shows a strong resilience to the effect of range expansion.
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Affiliation(s)
- Margarita Takou
- Institute of Botany, University of Cologne, Cologne, Germany
| | - Tuomas Hämälä
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Evan M Koch
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Kim A Steige
- Institute of Botany, University of Cologne, Cologne, Germany
| | | | - Levi Yant
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Mathieu Genete
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Shamil Sunyaev
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Vincent Castric
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Xavier Vekemans
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Outi Savolainen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
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12
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Durand E, Chantreau M, Le Veve A, Stetsenko R, Dubin M, Genete M, Llaurens V, Poux C, Roux C, Billiard S, Vekemans X, Castric V. Evolution of self-incompatibility in the Brassicaceae: Lessons from a textbook example of natural selection. Evol Appl 2020; 13:1279-1297. [PMID: 32684959 PMCID: PMC7359833 DOI: 10.1111/eva.12933] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/14/2022] Open
Abstract
Self-incompatibility (SI) is a self-recognition genetic system enforcing outcrossing in hermaphroditic flowering plants and results in one of the arguably best understood forms of natural (balancing) selection maintaining genetic variation over long evolutionary times. A rich theoretical and empirical population genetics literature has considerably clarified how the distribution of SI phenotypes translates into fitness differences among individuals by a combination of inbreeding avoidance and rare-allele advantage. At the same time, the molecular mechanisms by which self-pollen is specifically recognized and rejected have been described in exquisite details in several model organisms, such that the genotype-to-phenotype map is also pretty well understood, notably in the Brassicaceae. Here, we review recent advances in these two fronts and illustrate how the joint availability of detailed characterization of genotype-to-phenotype and phenotype-to-fitness maps on a single genetic system (plant self-incompatibility) provides the opportunity to understand the evolutionary process in a unique perspective, bringing novel insight on general questions about the emergence, maintenance, and diversification of a complex genetic system.
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Affiliation(s)
| | | | - Audrey Le Veve
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | | | - Manu Dubin
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Mathieu Genete
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Violaine Llaurens
- Institut de Systématique, Evolution et Biodiversité (ISYEB)Muséum national d'Histoire naturelleCNRS, Sorbonne Université, EPHE, Université des Antilles CP 5057 rue Cuvier, 75005 ParisFrance
| | - Céline Poux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
| | - Camille Roux
- CNRSUniv. LilleUMR 8198 ‐ Evo‐Eco‐PaleoF-59000 LilleFrance
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Base-Pairing Requirements for Small RNA-Mediated Gene Silencing of Recessive Self-Incompatibility Alleles in Arabidopsis halleri. Genetics 2020; 215:653-664. [PMID: 32461267 DOI: 10.1534/genetics.120.303351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022] Open
Abstract
Small noncoding RNAs are central regulators of genome activity and stability. Their regulatory function typically involves sequence similarity with their target sites, but understanding the criteria by which they specifically recognize and regulate their targets across the genome remains a major challenge in the field, especially in the face of the diversity of silencing pathways involved. The dominance hierarchy among self-incompatibility alleles in Brassicaceae is controlled by interactions between a highly diversified set of small noncoding RNAs produced by dominant S-alleles and their corresponding target sites on recessive S-alleles. By controlled crosses, we created numerous heterozygous combinations of S-alleles in Arabidopsis halleri and developed an real-time quantitative PCR assay to compare allele-specific transcript levels for the pollen determinant of self-incompatibility (SCR). This provides the unique opportunity to evaluate the precise base-pairing requirements for effective transcriptional regulation of this target gene. We found strong transcriptional silencing of recessive SCR alleles in all heterozygote combinations examined. A simple threshold model of base pairing for the small RNA-target interaction captures most of the variation in SCR transcript levels. For a subset of S-alleles, we also measured allele-specific transcript levels of the determinant of pistil specificity (SRK), and found sharply distinct expression dynamics throughout flower development between SCR and SRK In contrast to SCR, both SRK alleles were expressed at similar levels in the heterozygote genotypes examined, suggesting no transcriptional control of dominance for this gene. We discuss the implications for the evolutionary processes associated with the origin and maintenance of the dominance hierarchy among self-incompatibility alleles.
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