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Kauai F, Bafort Q, Mortier F, Van Montagu M, Bonte D, Van de Peer Y. Interspecific transfer of genetic information through polyploid bridges. Proc Natl Acad Sci U S A 2024; 121:e2400018121. [PMID: 38748576 PMCID: PMC11126971 DOI: 10.1073/pnas.2400018121] [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] [Received: 01/01/2024] [Accepted: 04/15/2024] [Indexed: 05/27/2024] Open
Abstract
Hybridization blurs species boundaries and leads to intertwined lineages resulting in reticulate evolution. Polyploidy, the outcome of whole genome duplication (WGD), has more recently been implicated in promoting and facilitating hybridization between polyploid species, potentially leading to adaptive introgression. However, because polyploid lineages are usually ephemeral states in the evolutionary history of life it is unclear whether WGD-potentiated hybridization has any appreciable effect on their diploid counterparts. Here, we develop a model of cytotype dynamics within mixed-ploidy populations to demonstrate that polyploidy can in fact serve as a bridge for gene flow between diploid lineages, where introgression is fully or partially hampered by the species barrier. Polyploid bridges emerge in the presence of triploid organisms, which despite critically low levels of fitness, can still allow the transfer of alleles between diploid states of independently evolving mixed-ploidy species. Notably, while marked genetic divergence prevents polyploid-mediated interspecific gene flow, we show that increased recombination rates can offset these evolutionary constraints, allowing a more efficient sorting of alleles at higher-ploidy levels before introgression into diploid gene pools. Additionally, we derive an analytical approximation for the rate of gene flow at the tetraploid level necessary to supersede introgression between diploids with nonzero introgression rates, which is especially relevant for plant species complexes, where interspecific gene flow is ubiquitous. Altogether, our results illustrate the potential impact of polyploid bridges on the (re)distribution of genetic material across ecological communities during evolution, representing a potential force behind reticulation.
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Affiliation(s)
- Felipe Kauai
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent9052, Belgium
- Center for Plant Systems Biology, Bioinformatics and Evolutionary Genomics, VIB, Gent9052, Belgium
- Department of Biology, Terrestrial Ecology Unit, Ghent University, Gent9000, Belgium
| | - Quinten Bafort
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent9052, Belgium
- Center for Plant Systems Biology, Bioinformatics and Evolutionary Genomics, VIB, Gent9052, Belgium
| | - Frederik Mortier
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent9052, Belgium
- Center for Plant Systems Biology, Bioinformatics and Evolutionary Genomics, VIB, Gent9052, Belgium
- Department of Biology, Terrestrial Ecology Unit, Ghent University, Gent9000, Belgium
| | - Marc Van Montagu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent9052, Belgium
- Center for Plant Systems Biology, Bioinformatics and Evolutionary Genomics, VIB, Gent9052, Belgium
| | - Dries Bonte
- Department of Biology, Terrestrial Ecology Unit, Ghent University, Gent9000, Belgium
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent9052, Belgium
- Center for Plant Systems Biology, Bioinformatics and Evolutionary Genomics, VIB, Gent9052, Belgium
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria0028, South Africa
- College of Horticulture, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing210095, China
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Pašakinskienė I. Festuca pratensis-like Subgenome Reassembly from a "Chromosomal Cocktail" in the Intergeneric Festulolium (Poaceae) Hybrid: A Rare Chromoanagenesis Event in Grasses. PLANTS (BASEL, SWITZERLAND) 2023; 12:984. [PMID: 36903845 PMCID: PMC10005718 DOI: 10.3390/plants12050984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Festuca and Lolium grass species are used for Festulolium hybrid variety production where they display trait complementarities. However, at the genome level, they show antagonisms and a broad scale of rearrangements. A rare case of an unstable hybrid, a donor plant manifesting pronounced variability of its clonal parts, was discovered in the F2 group of 682 plants of Lolium multiflorum × Festuca arundinacea (2n = 6x = 42). Five phenotypically distinct clonal plants were determined to be diploids, having only 14 chromosomes out of the 42 in the donor. GISH defined the diploids as having the basic genome from F. pratensis (2n = 2x = 14), one of the progenitors of F. arundinacea (2n = 6x = 42), with minor components from L. multiflorum and another subgenome, F. glaucescens. The 45S rDNA position on two chromosomes also corresponded to the variant of F. pratensis in the F. arundinacea parent. In the highly unbalanced donor genome, F. pratensis was the least represented, but the most involved in numerous recombinant chromosomes. Specifically, FISH highlighted 45S rDNA-containing clusters involved in the formation of unusual chromosomal associations in the donor plant, suggesting their active role in karyotype realignment. The results of this study show that F. pratensis chromosomes have a particular fundamental drive for restructuring, which prompts the disassembly/reassembly processes. The finding of F. pratensis "escaping" and rebuilding itself from the chaotic "chromosomal cocktail" of the donor plant points to a rare chromoanagenesis event and extends the view of plant genome plasticity.
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Affiliation(s)
- Izolda Pašakinskienė
- Life Sciences Centre, Vilnius University, Saulėtekio 7, 10221 Vilnius, Lithuania;
- Botanical Garden of Vilnius University, Kairėnų 43, 10239 Vilnius, Lithuania
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Karyotype and leaf epidermis histology traits of Digitaria abyssinica (Hochst. Ex A. Rich.) (Poaceae). Biologia (Bratisl) 2020. [DOI: 10.2478/s11756-020-00630-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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