1
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Lujan SA, Garbacz MA, Liberti SE, Burkholder AB, Kunkel TA. Instability throughout the Saccharomyces cerevisiae genome resulting from Pms1 endonuclease deficiency. Nucleic Acids Res 2024; 52:9574-9585. [PMID: 39016170 PMCID: PMC11381345 DOI: 10.1093/nar/gkae616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/25/2024] [Accepted: 07/06/2024] [Indexed: 07/18/2024] Open
Abstract
The endonuclease activity of Pms1 directs mismatch repair by generating a nick in the newly replicated DNA strand. Inactivating Pms2, the human homologue of yeast Pms1, increases the chances of colorectal and uterine cancers. Here we use whole genome sequencing to show that loss of this endonuclease activity, via the pms1-DE variant, results in strong mutator effects throughout the Saccharomyces cerevisiae genome. Mutation rates are strongly increased for mutations resulting from all types of single-base substitutions and for a wide variety of single- and multi-base indel mutations. Rates for these events are further increased in strains combining pms1-DE with mutator variants of each of the three major leading and lagging strand replicases. In all cases, mutation rates, spectra, biases, and context preferences are statistically indistinguishable from strains with equivalent polymerases but lacking initial mismatch recognition due to deletion of MSH2. This implies that, across the nuclear genome, strand discrimination via the Pms1 endonuclease is as important for MMR as is initial mismatch recognition by Msh2 heterodimers.
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Affiliation(s)
- Scott A Lujan
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, NC 27709, USA
| | - Marta A Garbacz
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, NC 27709, USA
- Currently Marta A. Garbacz works at Exact Sciences Corporation, Torrey Pines Science Park, La Jolla, CA 92037, USA
| | | | - Adam B Burkholder
- Office of Environmental Science Cyberinfrastructure, NIH/NIEHS, DHHS. Research Triangle Park, NC 27709, USA
| | - Thomas A Kunkel
- Genome Integrity & Structural Biology Laboratory, NIH/NIEHS, DHHS, Research Triangle Park, NC 27709, USA
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2
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Joshi S, Dash S, Vijayan N, Nishant KT. Irc20 modulates LOH frequency and distribution in S. cerevisiae. DNA Repair (Amst) 2024; 141:103727. [PMID: 39098164 DOI: 10.1016/j.dnarep.2024.103727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 06/04/2024] [Accepted: 07/09/2024] [Indexed: 08/06/2024]
Abstract
Loss of Heterozygosity (LOH) due to mitotic recombination is frequently associated with the development of various cancers (e.g. retinoblastoma). LOH is also an important source of genetic diversity, especially in organisms where meiosis is infrequent. Irc20 is a putative helicase, and E3 ubiquitin ligase involved in DNA double-strand break repair pathway. We analyzed genome-wide LOH events, gross chromosomal changes, small insertion-deletions and single nucleotide mutations in eleven S. cerevisiae mutation accumulation lines of irc20∆, which underwent 50 mitotic bottlenecks. LOH enhancement in irc20∆ was small (1.6 fold), but statistically significant as compared to the wild type. Short (≤ 1 kb) and long (> 10 kb) LOH tracts were significantly enhanced in irc20∆. Both interstitial and terminal LOH events were also significantly enhanced in irc20∆ compared to the wild type. LOH events in irc20∆ were more telomere proximal and away from centromeres compared to the wild type. Gross chromosomal changes, single nucleotide mutations and in-dels were comparable between irc20∆ and wild type. Locus based and genome-wide analysis of meiotic recombination showed that meiotic crossover frequencies are not altered in irc20∆. These results suggest Irc20 primarily regulates mitotic recombination and does not affect meiotic crossovers. Our results suggest that the IRC20 gene is important for regulating LOH frequency and distribution.
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Affiliation(s)
- Sameer Joshi
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Suman Dash
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Nikilesh Vijayan
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Koodali T Nishant
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India; Center for High-Performance Computing, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India.
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3
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Overton MS, Guy SE, Chen X, Martsul A, Carolino K, Akbari OS, Meyer JR, Kryazhimskiy S. Upper Bound on the Mutational Burden Imposed by a CRISPR-Cas9 Gene-Drive Element. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.569142. [PMID: 38076841 PMCID: PMC10705488 DOI: 10.1101/2023.11.28.569142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
CRISPR-Cas9 gene drives (CCGDs) are powerful tools for genetic control of wild populations, useful for eradication of disease vectors, conservation of endangered species and other applications. However, Cas9 alone and in a complex with gRNA can cause double-stranded DNA breaks at off-target sites, which could increase the mutational load and lead to loss of heterozygosity (LOH). These undesired effects raise potential concerns about the long-term evolutionary safety of CCGDs, but the magnitude of these effects is unknown. To estimate how the presence of a CCGD or a Cas9 alone in the genome affects the rates of LOH events and de novo mutations, we carried out a mutation accumulation experiment in yeast Saccharomyces cerevisiae. Despite its substantial statistical power, our experiment revealed no detectable effect of CCGD or Cas9 alone on the genome-wide rates of mutations or LOH events, suggesting that these rates are affected by less than 30%. Nevertheless, we found that Cas9 caused a slight but significant shift towards more interstitial and fewer terminal LOH events, and the CCGD caused a significant difference in the distribution of LOH events on Chromosome V. Taken together, our results show that these genetic elements impose a weak and likely localized additional mutational burden in the yeast model. Although the mutagenic effects of CCGDs need to be further evaluated in other systems, our results suggest that the effect of CCGDs on off-target mutation rates and genetic diversity may be acceptable.
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Affiliation(s)
- Michael S. Overton
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
| | - Sean E. Guy
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
- Current address: Bionano Genomics, San Diego, CA 92121
| | - Xingsen Chen
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
- Current address: Department of Entomology, University of Arizona, Tucson, Arizona, USA
| | - Alena Martsul
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
- Current address: Illumina Inc., San Diego, CA 92122
| | - Krypton Carolino
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
| | - Omar S. Akbari
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Justin R. Meyer
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
| | - Sergey Kryazhimskiy
- Department of Ecology, Behavior and Evolution, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093
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4
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Smukowski Heil C. Loss of Heterozygosity and Its Importance in Evolution. J Mol Evol 2023; 91:369-377. [PMID: 36752826 PMCID: PMC10276065 DOI: 10.1007/s00239-022-10088-8] [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: 09/14/2022] [Accepted: 12/23/2022] [Indexed: 02/09/2023]
Abstract
Loss of heterozygosity (LOH) is a mitotic recombination event that converts heterozygous loci to homozygous loci. This mutation event is widespread in organisms that have asexual reproduction like budding yeasts, and is also an important and frequent mutation event in tumorigenesis. Mutation accumulation studies have demonstrated that LOH occurs at a rate higher than the point mutation rate, and can impact large portions of the genome. Laboratory evolution experiments of heterozygous yeasts have revealed that LOH often unmasks beneficial recessive alleles that can confer large fitness advantages. Here, I highlight advances in understanding dominance, fitness, and phenotypes in laboratory evolved heterozygous yeast strains. I discuss best practices for detecting LOH in intraspecific and interspecific evolved clones and populations. Utilizing heterozygous strain backgrounds in laboratory evolution experiments offers an opportunity to advance our understanding of this important mutation type in shaping adaptation and genome evolution in wild, domesticated, and clinical populations.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
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5
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Sui Y, Epstein A, Dominska M, Zheng DQ, Petes T, Klein H. Ribodysgenesis: sudden genome instability in the yeast Saccharomyces cerevisiae arising from RNase H2 cleavage at genomic-embedded ribonucleotides. Nucleic Acids Res 2022; 50:6890-6902. [PMID: 35748861 PMCID: PMC9262587 DOI: 10.1093/nar/gkac536] [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] [Revised: 05/27/2022] [Accepted: 06/07/2022] [Indexed: 12/24/2022] Open
Abstract
Ribonucleotides can be incorporated into DNA during replication by the replicative DNA polymerases. These aberrant DNA subunits are efficiently recognized and removed by Ribonucleotide Excision Repair, which is initiated by the heterotrimeric enzyme RNase H2. While RNase H2 is essential in higher eukaryotes, the yeast Saccharomyces cerevisiae can survive without RNase H2 enzyme, although the genome undergoes mutation, recombination and other genome instability events at an increased rate. Although RNase H2 can be considered as a protector of the genome from the deleterious events that can ensue from recognition and removal of embedded ribonucleotides, under conditions of high ribonucleotide incorporation and retention in the genome in a RNase H2-negative strain, sudden introduction of active RNase H2 causes massive DNA breaks and genome instability in a condition which we term 'ribodysgenesis'. The DNA breaks and genome instability arise solely from RNase H2 cleavage directed to the ribonucleotide-containing genome. Survivors of ribodysgenesis have massive loss of heterozygosity events stemming from recombinogenic lesions on the ribonucleotide-containing DNA, with increases of over 1000X from wild-type. DNA breaks are produced over one to two divisions and subsequently cells adapt to RNase H2 and ribonucleotides in the genome and grow with normal levels of genome instability.
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Affiliation(s)
- Yang Sui
- State Key Laboratory of Motor Vehicle Biofuel Technology, Ocean College, Zhejiang University, Zhoushan 316021, China,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Anastasiya Epstein
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Margaret Dominska
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Dao-Qiong Zheng
- State Key Laboratory of Motor Vehicle Biofuel Technology, Ocean College, Zhejiang University, Zhoushan 316021, China,Hainan Institute of Zhejiang University, Sanya 572000, China,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, China
| | - Thomas D Petes
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hannah L Klein
- To whom correspondence should be addressed. Tel: +1 212 263 5778;
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6
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Tutaj H, Pirog A, Tomala K, Korona R. Genome-scale patterns in the loss of heterozygosity incidence in Saccharomyces cerevisiae. Genetics 2022; 221:6536968. [PMID: 35212738 PMCID: PMC9071580 DOI: 10.1093/genetics/iyac032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/17/2022] [Indexed: 02/07/2023] Open
Abstract
Former studies have established that loss of heterozygosity can be a key driver of sequence evolution in unicellular eukaryotes and tissues of metazoans. However, little is known about whether the distribution of loss of heterozygosity events is largely random or forms discernible patterns across genomes. To initiate our experiments, we introduced selectable markers to both arms of all chromosomes of the budding yeast. Subsequent extensive assays, repeated over several genetic backgrounds and environments, provided a wealth of information on the genetic and environmental determinants of loss of heterozygosity. Three findings stand out. First, the number of loss of heterozygosity events per unit time was more than 25 times higher for growing than starving cells. Second, loss of heterozygosity was most frequent when regions of homology around a recombination site were identical, about a half-% sequence divergence was sufficient to reduce its incidence. Finally, the density of loss of heterozygosity events was highly dependent on the genome's physical architecture. It was several-fold higher on short chromosomal arms than on long ones. Comparably large differences were seen within a single arm where regions close to a centromere were visibly less affected than regions close, though usually not strictly adjacent, to a telomere. We suggest that the observed uneven distribution of loss of heterozygosity events could have been caused not only by an uneven density of initial DNA damages. Location-depended differences in the mode of DNA repair, or its effect on fitness, were likely to operate as well.
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Affiliation(s)
- Hanna Tutaj
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Cracow, Poland
| | - Adrian Pirog
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Cracow, Poland
| | - Katarzyna Tomala
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Cracow, Poland
| | - Ryszard Korona
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Cracow, Poland,Corresponding author: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa Street 7, 30-387 Krakow, Poland.
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7
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Heasley LR, Argueso JL. Genomic characterization of a wild diploid isolate of Saccharomyces cerevisiae reveals an extensive and dynamic landscape of structural variation. Genetics 2021; 220:6428545. [PMID: 34791219 PMCID: PMC9176296 DOI: 10.1093/genetics/iyab193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/22/2021] [Indexed: 11/15/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae has been extensively characterized for many decades and is a critical resource for the study of numerous facets of eukaryotic biology. Recently, whole genome sequence analysis of over 1000 natural isolates of S. cerevisiae has provided critical insights into the evolutionary landscape of this species by revealing a population structure comprised of numerous genomically diverse lineages. These survey-level analyses have been largely devoid of structural genomic information, mainly because short read sequencing is not suitable for detailed characterization of genomic architecture. Consequently, we still lack a complete perspective of the genomic variation the exists within the species. Single molecule long read sequencing technologies, such as Oxford Nanopore and PacBio, provide sequencing-based approaches with which to rigorously define the structure of a genome, and have empowered yeast geneticists to explore this poorly described realm of eukaryotic genomics. Here, we present the comprehensive genomic structural analysis of a wild diploid isolate of S. cerevisiae, YJM311. We used long read sequence analysis to construct a haplotype-phased, telomere-to-telomere length assembly of the YJM311 genome and characterized the structural variations (SVs) therein. We discovered that the genome of YJM311 contains significant intragenomic structural variation, some of which imparts notable consequences to the genomic stability and developmental biology of the strain. Collectively, we outline a new methodology for creating accurate haplotype-phased genome assemblies and highlight how such genomic analyses can define the structural architectures of S. cerevisiae isolates. It is our hope that continued structural characterization of S. cerevisiae genomes, such as we have reported here for YJM311, will comprehensively advance our understanding of eukaryotic genome structure-function relationships, structural genomic diversity, and evolution.
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Affiliation(s)
- Lydia R Heasley
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
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8
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Mozzachiodi S, Tattini L, Llored A, Irizar A, Škofljanc N, D'Angiolo M, De Chiara M, Barré BP, Yue JX, Lutazi A, Loeillet S, Laureau R, Marsit S, Stenberg S, Albaud B, Persson K, Legras JL, Dequin S, Warringer J, Nicolas A, Liti G. Aborting meiosis allows recombination in sterile diploid yeast hybrids. Nat Commun 2021; 12:6564. [PMID: 34772931 PMCID: PMC8589840 DOI: 10.1038/s41467-021-26883-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 10/20/2021] [Indexed: 12/03/2022] Open
Abstract
Hybrids between diverged lineages contain novel genetic combinations but an impaired meiosis often makes them evolutionary dead ends. Here, we explore to what extent an aborted meiosis followed by a return-to-growth (RTG) promotes recombination across a panel of 20 Saccharomyces cerevisiae and S. paradoxus diploid hybrids with different genomic structures and levels of sterility. Genome analyses of 275 clones reveal that RTG promotes recombination and generates extensive regions of loss-of-heterozygosity in sterile hybrids with either a defective meiosis or a heavily rearranged karyotype, whereas RTG recombination is reduced by high sequence divergence between parental subgenomes. The RTG recombination preferentially arises in regions with low local heterozygosity and near meiotic recombination hotspots. The loss-of-heterozygosity has a profound impact on sexual and asexual fitness, and enables genetic mapping of phenotypic differences in sterile lineages where linkage analysis would fail. We propose that RTG gives sterile yeast hybrids access to a natural route for genome recombination and adaptation.
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Grants
- This work was supported by Agence Nationale de la Recherche (ANR-11-LABX-0028-01, ANR-13-BSV6-0006-01, ANR-15-IDEX-01, ANR-16-CE12-0019 and ANR-18-CE12-0004), Fondation pour la Recherche Médicale (FRM EQU202003010413), CEFIPRA, Cancéropôle PACA (AAP Equipment 2018), Meiogenix and the Swedish Research Council (2014-6547, 2014-4605 and 2018-03638). S.Mo. is funded by the convention CIFRE 2016/0582 between Meiogenix and ANRT. The Institut Curie NGS platform is supported by ANR-10-EQPX-03 (Equipex), ANR-10-INBS-09-08 (France Génomique Consortium), ITMO-CANCER and SiRIC INCA-DGOS (4654 program).
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Affiliation(s)
- Simone Mozzachiodi
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
- Meiogenix, 38, rue Servan, Paris, 75011, France
| | | | - Agnes Llored
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | | | - Neža Škofljanc
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | | | | | | | - Jia-Xing Yue
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Angela Lutazi
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Sophie Loeillet
- Institut Curie, Centre de Recherche, CNRS-UMR3244, PSL Research University, Paris, 75005, France
| | - Raphaelle Laureau
- Institut Curie, Centre de Recherche, CNRS-UMR3244, PSL Research University, Paris, 75005, France
- Department of Genetics and Development, Hammer Health Sciences Center, Columbia University Medical Center, New York, NY, USA
| | - Souhir Marsit
- Institut Curie, Centre de Recherche, CNRS-UMR3244, PSL Research University, Paris, 75005, France
- SPO, Université Montpellier, INRAE, Montpellier SupAgro, Montpellier, France
- Département de Biologie Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Québec, Canada
| | - Simon Stenberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Benoit Albaud
- Institut Curie, ICGEX NGS Platform, Paris, 75005, France
| | - Karl Persson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Jean-Luc Legras
- SPO, Université Montpellier, INRAE, Montpellier SupAgro, Montpellier, France
| | - Sylvie Dequin
- SPO, Université Montpellier, INRAE, Montpellier SupAgro, Montpellier, France
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Alain Nicolas
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
- Meiogenix, 38, rue Servan, Paris, 75011, France
- Institut Curie, Centre de Recherche, CNRS-UMR3244, PSL Research University, Paris, 75005, France
| | - Gianni Liti
- Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France.
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9
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Kiktev DA, Dominska M, Zhang T, Dahl J, Stepchenkova EI, Mieczkowski P, Burgers PM, Lujan S, Burkholder A, Kunkel TA, Petes TD. The fidelity of DNA replication, particularly on GC-rich templates, is reduced by defects of the Fe-S cluster in DNA polymerase δ. Nucleic Acids Res 2021; 49:5623-5636. [PMID: 34019669 PMCID: PMC8191807 DOI: 10.1093/nar/gkab371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/22/2021] [Accepted: 05/16/2021] [Indexed: 11/12/2022] Open
Abstract
Iron-sulfur clusters (4Fe–4S) exist in many enzymes concerned with DNA replication and repair. The contribution of these clusters to enzymatic activity is not fully understood. We identified the MET18 (MMS19) gene of Saccharomyces cerevisiae as a strong mutator on GC-rich genes. Met18p is required for the efficient insertion of iron-sulfur clusters into various proteins. met18 mutants have an elevated rate of deletions between short flanking repeats, consistent with increased DNA polymerase slippage. This phenotype is very similar to that observed in mutants of POL3 (encoding the catalytic subunit of Pol δ) that weaken binding of the iron-sulfur cluster. Comparable mutants of POL2 (Pol ϵ) do not elevate deletions. Further support for the conclusion that met18 strains result in impaired DNA synthesis by Pol δ are the observations that Pol δ isolated from met18 strains has less bound iron and is less processive in vitro than the wild-type holoenzyme.
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Affiliation(s)
- Denis A Kiktev
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Margaret Dominska
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Tony Zhang
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Joseph Dahl
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Elena I Stepchenkova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, St. Petersburg, Russia.,Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, St. Petersburg, Russia
| | - Piotr Mieczkowski
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7264, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Scott Lujan
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Adam Burkholder
- Office of Environmental Science Cyberinfrastructure, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Thomas D Petes
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
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10
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Dutta A, Dutreux F, Schacherer J. Loss of heterozygosity results in rapid but variable genome homogenization across yeast genetic backgrounds. eLife 2021; 10:70339. [PMID: 34159898 PMCID: PMC8245132 DOI: 10.7554/elife.70339] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/11/2021] [Indexed: 12/12/2022] Open
Abstract
The dynamics and diversity of the appearance of genetic variants play an essential role in the evolution of the genome and the shaping of biodiversity. Recent population-wide genome sequencing surveys have highlighted the importance of loss of heterozygosity (LOH) events and have shown that they are a neglected part of the genetic diversity landscape. To assess the extent, variability, and spectrum, we explored the accumulation of LOH events in 169 heterozygous diploid Saccharomyces cerevisiae mutation accumulation lines across nine genetic backgrounds. In total, we detected a large set of 22,828 LOH events across distinct genetic backgrounds with a heterozygous level ranging from 0.1% to 1%. LOH events are very frequent with a rate consistently much higher than the mutation rate, showing their importance for genome evolution. We observed that the interstitial LOH (I-LOH) events, resulting in internal short LOH tracts, were much frequent (n = 19,660) than the terminal LOH (T-LOH) events, that is, tracts extending to the end of the chromosome (n = 3168). However, the spectrum, the rate, and the fraction of the genome under LOH vary across genetic backgrounds. Interestingly, we observed that the more the ancestors were heterozygous, the more they accumulated T-LOH events. In addition, frequent short I-LOH tracts are a signature of the lines derived from hybrids with low spore fertility. Finally, we found lines showing almost complete homozygotization during vegetative progression. Overall, our results highlight that the variable dynamics of the LOH accumulation across distinct genetic backgrounds might lead to rapid differential genome evolution during vegetative growth.
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Affiliation(s)
- Abhishek Dutta
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Fabien Dutreux
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France.,Institut Universitaire de France (IUF), Paris, France
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11
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Stability across the Whole Nuclear Genome in the Presence and Absence of DNA Mismatch Repair. Cells 2021; 10:cells10051224. [PMID: 34067668 PMCID: PMC8156620 DOI: 10.3390/cells10051224] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 01/06/2023] Open
Abstract
We describe the contribution of DNA mismatch repair (MMR) to the stability of the eukaryotic nuclear genome as determined by whole-genome sequencing. To date, wild-type nuclear genome mutation rates are known for over 40 eukaryotic species, while measurements in mismatch repair-defective organisms are fewer in number and are concentrated on Saccharomyces cerevisiae and human tumors. Well-studied organisms include Drosophila melanogaster and Mus musculus, while less genetically tractable species include great apes and long-lived trees. A variety of techniques have been developed to gather mutation rates, either per generation or per cell division. Generational rates are described through whole-organism mutation accumulation experiments and through offspring–parent sequencing, or they have been identified by descent. Rates per somatic cell division have been estimated from cell line mutation accumulation experiments, from systemic variant allele frequencies, and from widely spaced samples with known cell divisions per unit of tissue growth. The latter methods are also used to estimate generational mutation rates for large organisms that lack dedicated germlines, such as trees and hyphal fungi. Mechanistic studies involving genetic manipulation of MMR genes prior to mutation rate determination are thus far confined to yeast, Arabidopsis thaliana, Caenorhabditis elegans, and one chicken cell line. A great deal of work in wild-type organisms has begun to establish a sound baseline, but far more work is needed to uncover the variety of MMR across eukaryotes. Nonetheless, the few MMR studies reported to date indicate that MMR contributes 100-fold or more to genome stability, and they have uncovered insights that would have been impossible to obtain using reporter gene assays.
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12
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Gorkovskiy A, Verstrepen KJ. The Role of Structural Variation in Adaptation and Evolution of Yeast and Other Fungi. Genes (Basel) 2021; 12:699. [PMID: 34066718 PMCID: PMC8150848 DOI: 10.3390/genes12050699] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 01/12/2023] Open
Abstract
Mutations in DNA can be limited to one or a few nucleotides, or encompass larger deletions, insertions, duplications, inversions and translocations that span long stretches of DNA or even full chromosomes. These so-called structural variations (SVs) can alter the gene copy number, modify open reading frames, change regulatory sequences or chromatin structure and thus result in major phenotypic changes. As some of the best-known examples of SV are linked to severe genetic disorders, this type of mutation has traditionally been regarded as negative and of little importance for adaptive evolution. However, the advent of genomic technologies uncovered the ubiquity of SVs even in healthy organisms. Moreover, experimental evolution studies suggest that SV is an important driver of evolution and adaptation to new environments. Here, we provide an overview of the causes and consequences of SV and their role in adaptation, with specific emphasis on fungi since these have proven to be excellent models to study SV.
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Affiliation(s)
- Anton Gorkovskiy
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
| | - Kevin J. Verstrepen
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
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13
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Nguyen DT, Wu B, Long H, Zhang N, Patterson C, Simpson S, Morris K, Thomas WK, Lynch M, Hao W. Variable Spontaneous Mutation and Loss of Heterozygosity among Heterozygous Genomes in Yeast. Mol Biol Evol 2021; 37:3118-3130. [PMID: 33219379 DOI: 10.1093/molbev/msaa150] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutation and recombination are the primary sources of genetic variation. To better understand the evolution of genetic variation, it is crucial to comprehensively investigate the processes involving mutation accumulation and recombination. In this study, we performed mutation accumulation experiments on four heterozygous diploid yeast species in the Saccharomycodaceae family to determine spontaneous mutation rates, mutation spectra, and losses of heterozygosity (LOH). We observed substantial variation in mutation rates and mutation spectra. We also observed high LOH rates (1.65-11.07×10-6 events per heterozygous site per cell division). Biases in spontaneous mutation and LOH together with selection ultimately shape the variable genome-wide nucleotide landscape in yeast species.
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Affiliation(s)
- Duong T Nguyen
- Department of Biological Sciences, Wayne State University, Detroit, MI
| | - Baojun Wu
- Department of Biological Sciences, Wayne State University, Detroit, MI
| | - Hongan Long
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, Shandong Province, China
| | - Nan Zhang
- Department of Biological Sciences, Wayne State University, Detroit, MI
| | | | | | | | | | - Michael Lynch
- Center for Mechanisms of Evolution, The Biodesign Institute, Arizona State University, Tempe, AZ
| | - Weilong Hao
- Department of Biological Sciences, Wayne State University, Detroit, MI
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14
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Abstract
DNA break lesions pose a serious threat to the integrity of the genome. Eukaryotic cells can repair these lesions using the homologous recombination pathway that guides the repair reaction by using a homologous DNA template. The budding yeast Saccharomyces cerevisiae is an excellent model system with which to study this repair mechanism and the resulting patterns of genomic change resulting from it. In this chapter, we describe an approach that utilizes whole-genome sequencing data to support the analysis of tracts of loss-of-heterozygosity (LOH) that can arise from mitotic recombination in the context of the entire diploid yeast genome. The workflow and the discussion in this chapter are intended to enable classically trained molecular biologists and geneticists with limited experience in computational methods to conceptually understand and execute the steps of genome-wide LOH analysis as well as to adapt and apply them to their own specific studies and experimental models.
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Affiliation(s)
- Lydia R Heasley
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Nadia M V Sampaio
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, USA
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA.
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, USA.
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15
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A yeast living ancestor reveals the origin of genomic introgressions. Nature 2020; 587:420-425. [PMID: 33177709 DOI: 10.1038/s41586-020-2889-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 08/11/2020] [Indexed: 11/08/2022]
Abstract
Genome introgressions drive evolution across the animal1, plant2 and fungal3 kingdoms. Introgressions initiate from archaic admixtures followed by repeated backcrossing to one parental species. However, how introgressions arise in reproductively isolated species, such as yeast4, has remained unclear. Here we identify a clonal descendant of the ancestral yeast hybrid that founded the extant Saccharomyces cerevisiae Alpechin lineage5, which carries abundant Saccharomyces paradoxus introgressions. We show that this clonal descendant, hereafter defined as a 'living ancestor', retained the ancestral genome structure of the first-generation hybrid with contiguous S. cerevisiae and S. paradoxus subgenomes. The ancestral first-generation hybrid underwent catastrophic genomic instability through more than a hundred mitotic recombination events, mainly manifesting as homozygous genome blocks generated by loss of heterozygosity. These homozygous sequence blocks rescue hybrid fertility by restoring meiotic recombination and are the direct origins of the introgressions present in the Alpechin lineage. We suggest a plausible route for introgression evolution through the reconstruction of extinct stages and propose that genome instability allows hybrids to overcome reproductive isolation and enables introgressions to emerge.
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16
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Sui Y, Qi L, Wu JK, Wen XP, Tang XX, Ma ZJ, Wu XC, Zhang K, Kokoska RJ, Zheng DQ, Petes TD. Genome-wide mapping of spontaneous genetic alterations in diploid yeast cells. Proc Natl Acad Sci U S A 2020; 117:28191-28200. [PMID: 33106417 PMCID: PMC7668089 DOI: 10.1073/pnas.2018633117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Genomic alterations including single-base mutations, deletions and duplications, translocations, mitotic recombination events, and chromosome aneuploidy generate genetic diversity. We examined the rates of all of these genetic changes in a diploid strain of Saccharomyces cerevisiae by whole-genome sequencing of many independent isolates (n = 93) subcloned about 100 times in unstressed growth conditions. The most common alterations were point mutations and small (<100 bp) insertion/deletions (n = 1,337) and mitotic recombination events (n = 1,215). The diploid cells of most eukaryotes are heterozygous for many single-nucleotide polymorphisms (SNPs). During mitotic cell divisions, recombination can produce derivatives of these cells that have become homozygous for the polymorphisms, termed loss-of-heterozygosity (LOH) events. LOH events can change the phenotype of the cells and contribute to tumor formation in humans. We observed two types of LOH events: interstitial events (conversions) resulting in a short LOH tract (usually less than 15 kb) and terminal events (mostly cross-overs) in which the LOH tract extends to the end of the chromosome. These two types of LOH events had different distributions, suggesting that they may have initiated by different mechanisms. Based on our results, we present a method of calculating the probability of an LOH event for individual SNPs located throughout the genome. We also identified several hotspots for chromosomal rearrangements (large deletions and duplications). Our results provide insights into the relative importance of different types of genetic alterations produced during vegetative growth.
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Affiliation(s)
- Yang Sui
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27705
| | - Lei Qi
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27705
| | - Jian-Kun Wu
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
| | - Xue-Ping Wen
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
| | - Xing-Xing Tang
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
| | - Zhong-Jun Ma
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China
| | - Xue-Chang Wu
- Institute of Microbiology, College of Life Science, Zhejiang University, 310058 Hangzhou, China
| | - Ke Zhang
- Institute of Microbiology, College of Life Science, Zhejiang University, 310058 Hangzhou, China;
| | - Robert J Kokoska
- Physical Sciences Directorate, United States Army Research Office, Research Triangle Park, NC 27709
| | - Dao-Qiong Zheng
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, 316021 Zhoushan, China;
| | - Thomas D Petes
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27705;
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17
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Loss of Heterozygosity and Base Mutation Rates Vary Among Saccharomyces cerevisiae Hybrid Strains. G3-GENES GENOMES GENETICS 2020; 10:3309-3319. [PMID: 32727920 PMCID: PMC7466981 DOI: 10.1534/g3.120.401551] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A growing body of evidence suggests that mutation rates exhibit intra-species specific variation. We estimated genome-wide loss of heterozygosity (LOH), gross chromosomal changes, and single nucleotide mutation rates to determine intra-species specific differences in hybrid and homozygous strains of Saccharomyces cerevisiae. The mutation accumulation lines of the S. cerevisiae hybrid backgrounds - S288c/YJM789 (S/Y) and S288c/RM11-1a (S/R) were analyzed along with the homozygous diploids RM11, S288c, and YJM145. LOH was extensive in both S/Y and S/R hybrid backgrounds. The S/Y background also showed longer LOH tracts, gross chromosomal changes, and aneuploidy. Short copy number aberrations were observed in the S/R background. LOH data from the S/Y and S/R hybrids were used to construct a LOH map for S288c to identify hotspots. Further, we observe up to a sixfold difference in single nucleotide mutation rates among the S. cerevisiae S/Y and S/R genetic backgrounds. Our results demonstrate LOH is common during mitotic divisions in S. cerevisiae hybrids and also highlight genome-wide differences in LOH patterns and rates of single nucleotide mutations between commonly used S. cerevisiae hybrid genetic backgrounds.
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18
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Hovhannisyan H, Saus E, Ksiezopolska E, Hinks Roberts AJ, Louis EJ, Gabaldón T. Integrative Omics Analysis Reveals a Limited Transcriptional Shock After Yeast Interspecies Hybridization. Front Genet 2020; 11:404. [PMID: 32457798 PMCID: PMC7221068 DOI: 10.3389/fgene.2020.00404] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/30/2020] [Indexed: 12/30/2022] Open
Abstract
The formation of interspecific hybrids results in the coexistence of two diverged genomes within the same nucleus. It has been hypothesized that negative epistatic interactions and regulatory interferences between the two sub-genomes may elicit a so-called genomic shock involving, among other alterations, broad transcriptional changes. To assess the magnitude of this shock in hybrid yeasts, we investigated the transcriptomic differences between a newly formed Saccharomyces cerevisiae × Saccharomyces uvarum diploid hybrid and its diploid parentals, which diverged ∼20 mya. RNA sequencing (RNA-Seq) based allele-specific expression (ASE) analysis indicated that gene expression changes in the hybrid genome are limited, with only ∼1-2% of genes significantly altering their expression with respect to a non-hybrid context. In comparison, a thermal shock altered six times more genes. Furthermore, differences in the expression between orthologous genes in the two parental species tended to be diminished for the corresponding homeologous genes in the hybrid. Finally, and consistent with the RNA-Seq results, we show a limited impact of hybridization on chromatin accessibility patterns, as assessed with assay for transposase-accessible chromatin using sequencing (ATAC-Seq). Overall, our results suggest a limited genomic shock in a newly formed yeast hybrid, which may explain the high frequency of successful hybridization in these organisms.
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Affiliation(s)
- Hrant Hovhannisyan
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ester Saus
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ewa Ksiezopolska
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Alex J. Hinks Roberts
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Edward J. Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Toni Gabaldón
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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19
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The Transcriptional Aftermath in Two Independently Formed Hybrids of the Opportunistic Pathogen Candida orthopsilosis. mSphere 2020; 5:5/3/e00282-20. [PMID: 32376704 PMCID: PMC7203458 DOI: 10.1128/msphere.00282-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
How new pathogens emerge is an important question that remains largely unanswered. Some emerging yeast pathogens are hybrids originated through the crossing of two different species, but how hybridization contributes to higher virulence is unclear. Here, we show that hybrids selectively retain gene regulation plasticity inherited from the two parents and that this plasticity affects genes involved in virulence. Interspecific hybridization can drive evolutionary adaptation to novel environments. The Saccharomycotina clade of budding yeasts includes many hybrid lineages, and hybridization has been proposed as a source for new pathogenic species. Candida orthopsilosis is an emerging opportunistic pathogen for which most clinical isolates are hybrids, each derived from one of at least four independent crosses between the same two parental lineages. To gain insight into the transcriptomic aftermath of hybridization in these pathogens, we analyzed allele-specific gene expression in two independently formed hybrid strains and in a homozygous strain representative of one parental lineage. Our results show that the effect of hybridization on overall gene expression is rather limited, affecting ∼4% of the genes studied. However, we identified a larger effect in terms of imbalanced allelic expression, affecting ∼9.5% of the heterozygous genes in the hybrids. This effect was larger in the hybrid with more extensive loss of heterozygosity, which may indicate a tendency to avoid loss of heterozygosity in these genes. Consistently, the number of shared genes with allele-specific expression in the two independently formed hybrids was higher than random expectation, suggesting selective retention. Some of the imbalanced genes have functions related to pathogenicity, including zinc transport and superoxide dismutase activities. While it remains unclear whether the observed imbalanced genes play a role in virulence, our results suggest that differences in allele-specific expression may add an additional layer of phenotypic plasticity to traits related to virulence in C. orthopsilosis hybrids. IMPORTANCE How new pathogens emerge is an important question that remains largely unanswered. Some emerging yeast pathogens are hybrids originated through the crossing of two different species, but how hybridization contributes to higher virulence is unclear. Here, we show that hybrids selectively retain gene regulation plasticity inherited from the two parents and that this plasticity affects genes involved in virulence.
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20
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Tattini L, Tellini N, Mozzachiodi S, D'Angiolo M, Loeillet S, Nicolas A, Liti G. Accurate Tracking of the Mutational Landscape of Diploid Hybrid Genomes. Mol Biol Evol 2020; 36:2861-2877. [PMID: 31397846 PMCID: PMC6878955 DOI: 10.1093/molbev/msz177] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutations, recombinations, and genome duplications may promote genetic diversity and trigger evolutionary processes. However, quantifying these events in diploid hybrid genomes is challenging. Here, we present an integrated experimental and computational workflow to accurately track the mutational landscape of yeast diploid hybrids (MuLoYDH) in terms of single-nucleotide variants, small insertions/deletions, copy-number variants, aneuploidies, and loss-of-heterozygosity. Pairs of haploid Saccharomyces parents were combined to generate ancestor hybrids with phased genomes and varying levels of heterozygosity. These diploids were evolved under different laboratory protocols, in particular mutation accumulation experiments. Variant simulations enabled the efficient integration of competitive and standard mapping of short reads, depending on local levels of heterozygosity. Experimental validations proved the high accuracy and resolution of our computational approach. Finally, applying MuLoYDH to four different diploids revealed striking genetic background effects. Homozygous Saccharomyces cerevisiae showed a ∼4-fold higher mutation rate compared with its closely related species S. paradoxus. Intraspecies hybrids unveiled that a substantial fraction of the genome (∼250 bp per generation) was shaped by loss-of-heterozygosity, a process strongly inhibited in interspecies hybrids by high levels of sequence divergence between homologous chromosomes. In contrast, interspecies hybrids exhibited higher single-nucleotide mutation rates compared with intraspecies hybrids. MuLoYDH provided an unprecedented quantitative insight into the evolutionary processes that mold diploid yeast genomes and can be generalized to other genetic systems.
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Affiliation(s)
- Lorenzo Tattini
- CNRS UMR7284, INSERM, IRCAN, Université Côte d'Azur, Nice, France
| | - Nicolò Tellini
- CNRS UMR7284, INSERM, IRCAN, Université Côte d'Azur, Nice, France
| | | | | | - Sophie Loeillet
- CNRS UMR3244, Institut Curie, PSL Research University, Paris, France
| | - Alain Nicolas
- CNRS UMR3244, Institut Curie, PSL Research University, Paris, France
| | - Gianni Liti
- CNRS UMR7284, INSERM, IRCAN, Université Côte d'Azur, Nice, France
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21
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James TY, Michelotti LA, Glasco AD, Clemons RA, Powers RA, James ES, Simmons DR, Bai F, Ge S. Adaptation by Loss of Heterozygosity in Saccharomyces cerevisiae Clones Under Divergent Selection. Genetics 2019; 213:665-683. [PMID: 31371407 PMCID: PMC6781901 DOI: 10.1534/genetics.119.302411] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/29/2019] [Indexed: 01/14/2023] Open
Abstract
Loss of heterozygosity (LOH) is observed during vegetative growth and reproduction of diploid genotypes through mitotic crossovers, aneuploidy caused by nondisjunction, and gene conversion. We aimed to test the role that LOH plays during adaptation of two highly heterozygous Saccharomyces cerevisiae genotypes to multiple environments over a short time span in the laboratory. We hypothesized that adaptation would be observed through parallel LOH events across replicate populations. Using genome resequencing of 70 clones, we found that LOH was widespread with 5.2 LOH events per clone after ∼500 generations. The most common mode of LOH was gene conversion (51%) followed by crossing over consistent with either break-induced replication or double Holliday junction resolution. There was no evidence that LOH involved nondisjunction of whole chromosomes. We observed parallel LOH in both an environment-specific and environment-independent manner. LOH largely involved recombining existing variation between the parental genotypes, but also was observed after de novo, presumably beneficial, mutations occurred in the presence of canavanine, a toxic analog of arginine. One highly parallel LOH event involved the ENA salt efflux pump locus on chromosome IV, which showed repeated LOH to the allele from the European parent, an allele originally derived by introgression from S. paradoxus Using CRISPR-engineered LOH we showed that the fitness advantage provided by this single LOH event was 27%. Overall, we found extensive evidence that LOH could be adaptive and is likely to be a greater source of initial variation than de novo mutation for rapid evolution of diploid genotypes.
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Affiliation(s)
- Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lucas A Michelotti
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alexander D Glasco
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Rebecca A Clemons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Robert A Powers
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Ellen S James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - D Rabern Simmons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Fengyan Bai
- Institute of Microbiology, Chinese Academy of Sciences, State Key Laboratory of Mycology, Chaoyang District, Beijing 100101, China
| | - Shuhua Ge
- Technology Development and Transfer Center, Institute of Microbiology, Chinese Academy of Sciences, Chaoyang District, Beijing 100029, China
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22
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Sampaio NMV, Watson RA, Argueso JL. Controlled Reduction of Genomic Heterozygosity in an Industrial Yeast Strain Reveals Wide Cryptic Phenotypic Variation. Front Genet 2019; 10:782. [PMID: 31572430 PMCID: PMC6749062 DOI: 10.3389/fgene.2019.00782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 07/24/2019] [Indexed: 01/12/2023] Open
Abstract
Abundant genomic heterozygosity can be found in wild strains of the budding yeast Saccharomyces cerevisiae isolated from industrial and clinical environments. The extent to which heterozygosity influences the phenotypes of these isolates is not fully understood. One such case is the PE-2/JAY270 strain, a natural hybrid widely adopted by sugarcane bioethanol distilleries for its ability to thrive under harsh biotic and abiotic stresses during industrial scale fermentation, however, it is not known whether or how the heterozygous configuration of the JAY270 genome contributes to its many desirable traits. In this study, we took a step toward exploring this question by conducting an initial functional characterization of JAY270’s heteroalleles. We manipulated the abundance and distribution of heterozygous alleles through inbreeding and targeted uniparental disomy (UPD). Unique combinations of homozygous alleles in each inbred strain revealed wide phenotypic variation for at least two important industrial traits: Heat stress tolerance and competitive growth. Quantitative trait loci analyses allowed the identification of broad genomic regions where genetic polymorphisms potentially impacted these traits, and there was no overlap between the loci associated with each. In addition, we adapted an approach to induce bidirectional UPD of three targeted pairs of chromosomes (IV, XIV, and XV), while heterozygosity was maintained elsewhere in the genome. In most cases UPD led to detectable phenotypic alterations, often in opposite directions between the two homozygous haplotypes in each UPD pair. Our results showed that both widespread and regional homozygosity could uncover cryptic phenotypic variation supported by the heteroalleles residing in the JAY270 genome. Interestingly, we characterized multiple examples of inbred and UPD strains that displayed heat tolerance or competitive growth phenotypes that were superior to their heterozygous parent. However, we propose that homozygosity for those regions may be associated with a decrease in overall fitness in the complex and dynamic distillery environment, and that may have contributed to slowing down the erosion of heterozygosity from the JAY270 genome. This study also laid a foundation for approaches that can be expanded to the identification of specific alleles of interest for industrial applications in this and other hybrid yeast strains.
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Affiliation(s)
- Nadia M V Sampaio
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States.,Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, United States
| | - Ruth A Watson
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States.,Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, United States
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23
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Charron G, Marsit S, Hénault M, Martin H, Landry CR. Spontaneous whole-genome duplication restores fertility in interspecific hybrids. Nat Commun 2019; 10:4126. [PMID: 31511504 PMCID: PMC6739354 DOI: 10.1038/s41467-019-12041-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/19/2019] [Indexed: 11/21/2022] Open
Abstract
Interspecies hybrids often show some advantages over parents but also frequently suffer from reduced fertility, which can sometimes be overcome through sexual reproduction that sorts out genetic incompatibilities. Sex is however inefficient due to the low viability or fertility of hybrid offspring and thus limits their evolutionary potential. Mitotic cell division could be an alternative to fertility recovery in species such as fungi that can also propagate asexually. Here, to test this, we evolve in parallel and under relaxed selection more than 600 diploid yeast inter-specific hybrids that span from 100,000 to 15 M years of divergence. We find that hybrids can recover fertility spontaneously and rapidly through whole-genome duplication. These events occur in both hybrids between young and well-established species. Our results show that the instability of ploidy in hybrid is an accessible path to spontaneous fertility recovery. Hybridization across species can lead to offspring with reduced fertility. Here, the authors experimentally evolve yeast and show that whole-genome duplication during asexual reproduction can restore fertility in hybrids over a relatively short evolutionary timespan.
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Affiliation(s)
- Guillaume Charron
- Institut de Biologie Intégrative et des Systèmes, 1030 avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biologie, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada
| | - Souhir Marsit
- Institut de Biologie Intégrative et des Systèmes, 1030 avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biologie, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biochimie, microbiologie et bio-informatique, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada
| | - Mathieu Hénault
- Institut de Biologie Intégrative et des Systèmes, 1030 avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biochimie, microbiologie et bio-informatique, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada
| | - Hélène Martin
- Institut de Biologie Intégrative et des Systèmes, 1030 avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biologie, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.,Département de biochimie, microbiologie et bio-informatique, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes, 1030 avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada. .,Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, (PROTEO), 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada. .,Département de biologie, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada. .,Département de biochimie, microbiologie et bio-informatique, 1045 Avenue de la Médecine, Université Laval, Québec (Qc), G1V 0A6, Canada.
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24
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Arbel‐Eden A, Simchen G. Elevated Mutagenicity in Meiosis and Its Mechanism. Bioessays 2019; 41:e1800235. [DOI: 10.1002/bies.201800235] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/31/2019] [Indexed: 12/25/2022]
Affiliation(s)
| | - Giora Simchen
- Department of GeneticsThe Hebrew University of JerusalemJerusalem 91904 Israel
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25
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Global analysis of mutations driving microevolution of a heterozygous diploid fungal pathogen. Proc Natl Acad Sci U S A 2018; 115:E8688-E8697. [PMID: 30150418 PMCID: PMC6140516 DOI: 10.1073/pnas.1806002115] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Candida albicans is a heterozygous diploid yeast that is a commensal of the human gastrointestinal tract and a prevalent opportunistic pathogen. Here, whole-genome sequencing was performed on multiple C. albicans isolates passaged both in vitro and in vivo to characterize the complete spectrum of mutations arising in laboratory culture and in the mammalian host. We establish that, independent of culture niche, microevolution is primarily driven by de novo base substitutions and frequent short-tract loss-of-heterozygosity events. An average base-substitution rate of ∼1.2 × 10-10 per base pair per generation was observed in vitro, with higher rates inferred during host infection. Large-scale chromosomal changes were relatively rare, although chromosome 7 trisomies frequently emerged during passaging in a gastrointestinal model and was associated with increased fitness for this niche. Multiple chromosomal features impacted mutational patterns, with mutation rates elevated in repetitive regions, subtelomeric regions, and in gene families encoding cell surface proteins involved in host adhesion. Strikingly, de novo mutation rates were more than 800-fold higher in regions immediately adjacent to emergent loss-of-heterozygosity tracts, indicative of recombination-induced mutagenesis. Furthermore, genomes showed biased patterns of mutations suggestive of extensive purifying selection during passaging. These results reveal how both cell-intrinsic and cell-extrinsic factors influence C. albicans microevolution, and provide a quantitative picture of genome dynamics in this heterozygous diploid species.
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Chakraborty P, Pankajam AV, Dutta A, Nishant KT. Genome wide analysis of meiotic recombination in yeast: For a few SNPs more. IUBMB Life 2018; 70:743-752. [PMID: 29934971 PMCID: PMC6120447 DOI: 10.1002/iub.1877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/02/2018] [Indexed: 01/08/2023]
Abstract
Diploid organisms undergo meiosis to produce haploid germ cells. Crossover events during meiosis promote genetic diversity and facilitate accurate chromosome segregation. The baker's yeast Saccharomyces cerevisiae is extensively used as a model for analysis of meiotic recombination. Conventional methods for measuring recombination events in S. cerevisiae have been limited by the number and density of genetic markers. Next generation sequencing (NGS)-based analysis of hybrid yeast genomes bearing thousands of heterozygous single nucleotide polymorphism (SNP) markers has revolutionized analysis of meiotic recombination. By facilitating analysis of marker segregation in the whole genome with unprecedented resolution, this method has resulted in the generation of high-resolution recombination maps in wild-type and meiotic mutants. These studies have provided novel insights into the mechanism of meiotic recombination. In this review, we discuss the methodology, challenges, insights and future prospects of using NGS-based methods for whole genome analysis of meiotic recombination. The objective is to facilitate the use of these high through-put sequencing methods for the analysis of meiotic recombination given their power to provide significant new insights into the process. © 2018 The Authors. IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 70(8):743-752, 2018.
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Affiliation(s)
- Parijat Chakraborty
- School of BiologyIndian Institute of Science Education and ResearchThiruvananthapuramTrivandrumIndia
| | - Ajith V. Pankajam
- School of BiologyIndian Institute of Science Education and ResearchThiruvananthapuramTrivandrumIndia
| | - Abhishek Dutta
- School of BiologyIndian Institute of Science Education and ResearchThiruvananthapuramTrivandrumIndia
| | - Koodali T. Nishant
- School of BiologyIndian Institute of Science Education and ResearchThiruvananthapuramTrivandrumIndia
- Centre for Computation Modelling and SimulationIndian Institute of Science Education and ResearchThiruvananthapuramTrivandrumIndia
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