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The Plant Journal : For Cell and... Nov 2023Crossovers (COs) are necessary for generating genetic diversity that breeders can select, but there are conserved mechanisms that regulate their frequency and...
Crossovers (COs) are necessary for generating genetic diversity that breeders can select, but there are conserved mechanisms that regulate their frequency and distribution. Increasing CO frequency may raise the efficiency of selection by increasing the chance of integrating more desirable traits. In this study, we characterize rice FANCM and explore its functions in meiotic CO control. FANCM mutations do not affect fertility in rice, but they cause a great boost in the overall frequency of COs in both inbred and hybrid rice, according to genetic analysis of the complete set of fancm zmm (hei10, ptd, shoc1, mer3, zip4, msh4, msh5, and heip1) mutants. Although the early homologous recombination events proceed normally in fancm, the meiotic extra COs are not marked with HEI10 and require MUS81 resolvase for resolution. FANCM depends on PAIR1, COM1, DMC1, and HUS1 to perform its functions. Simultaneous disruption of FANCM and MEICA1 synergistically increases CO frequency, but it is accompanied by nonhomologous chromosome associations and fragmentations. FANCM interacts with the MHF complex, and ablation of rice MHF1 or MHF2 could restore the formation of 12 bivalents in the absence of the ZMM gene ZIP4. Our data indicate that unleashing meiotic COs by mutating any member of the FANCM-MHF complex could be an effective procedure to accelerate the efficiency of rice breeding.
Topics: Oryza; DNA Helicases; Plant Breeding; Meiosis; Homologous Recombination; Crossing Over, Genetic
PubMed: 37632767
DOI: 10.1111/tpj.16399 -
Infection, Genetics and Evolution :... Jan 2018We review the sexual processes common in pathogenic microorganisms and assess the primary adaptive benefit of such processes. The pathogenic microorganisms considered... (Review)
Review
We review the sexual processes common in pathogenic microorganisms and assess the primary adaptive benefit of such processes. The pathogenic microorganisms considered include bacteria, microbial eukaryotes, and viruses. The sexual processes include bacterial transformation, eukaryotic meiotic sex and virus multiplicity reactivation. Recent evidence shows that sexual processes are common in microbial pathogens. A major general challenge to pathogen survival and infectivity is the need to overcome the hostile defenses of their target host. These defenses characteristically involve production of stresses, including oxidative stress, that can damage the pathogen's genome. Pathogens appear generally to possess enzyme systems that are central to sex and are also associated with a particular type of genomic repair process, recombinational repair. For some pathogens, it has been directly demonstrated that infectivity and virulence depend on sex. The evidence reviewed here supports the conclusion that the primary benefit of sex in pathogens is the repair of genomic damages that would otherwise be deleterious or lethal. This conclusion is in agreement with similar conclusions derived from non-pathogenic model species of bacteria, microbial eukaryotes and viruses. In several pathogenic species it has been shown that the two partner genomes that engage in sex are most often clonally related or closely related genetically. Thus, in pathogenic species, sexual interactions likely generate little or no genetic variation among progeny. However, infrequent outcrossing can occur in these sexual species and this may have important long term consequences.
Topics: Bacterial Physiological Phenomena; DNA Repair; Disease Susceptibility; Fungi; Host-Pathogen Interactions; Microbial Interactions; Microbiology; Recombination, Genetic; Transformation, Genetic; Virus Physiological Phenomena
PubMed: 29111273
DOI: 10.1016/j.meegid.2017.10.024 -
The EMBO Journal Aug 2023Meiotic recombination is initiated by the formation of DNA double-strand breaks (DSBs), essential for fertility and genetic diversity. In the mouse, DSBs are formed by...
Meiotic recombination is initiated by the formation of DNA double-strand breaks (DSBs), essential for fertility and genetic diversity. In the mouse, DSBs are formed by the catalytic TOPOVIL complex consisting of SPO11 and TOPOVIBL. To preserve genome integrity, the activity of the TOPOVIL complex is finely controlled by several meiotic factors including REC114, MEI4, and IHO1, but the underlying mechanism is poorly understood. Here, we report that mouse REC114 forms homodimers, that it associates with MEI4 as a 2:1 heterotrimer that further dimerizes, and that IHO1 forms coiled-coil-based tetramers. Using AlphaFold2 modeling combined with biochemical characterization, we uncovered the molecular details of these assemblies. Finally, we show that IHO1 directly interacts with the PH domain of REC114 by recognizing the same surface as TOPOVIBL and another meiotic factor ANKRD31. These results provide strong evidence for the existence of a ternary IHO1-REC114-MEI4 complex and suggest that REC114 could act as a potential regulatory platform mediating mutually exclusive interactions with several partners.
Topics: Animals; Mice; Cell Cycle Proteins; DNA; Homologous Recombination; Meiosis
PubMed: 37431931
DOI: 10.15252/embj.2023113866 -
Genome Biology Nov 2021Intermixing of genomes through meiotic reassortment and recombination of homologous chromosomes is a unifying theme of sexual reproduction in eukaryotic organisms and is...
BACKGROUND
Intermixing of genomes through meiotic reassortment and recombination of homologous chromosomes is a unifying theme of sexual reproduction in eukaryotic organisms and is considered crucial for their adaptive evolution. Previous studies of the budding yeast species Saccharomycodes ludwigii suggested that meiotic crossing over might be absent from its sexual life cycle, which is predominated by fertilization within the meiotic tetrad.
RESULTS
We demonstrate that recombination is extremely suppressed during meiosis in Sd. ludwigii. DNA double-strand break formation by the conserved transesterase Spo11, processing and repair involving interhomolog interactions are required for normal meiosis but do not lead to crossing over. Although the species has retained an intact meiotic gene repertoire, genetic and population analyses suggest the exceptionally rare occurrence of meiotic crossovers in its genome. A strong AT bias of spontaneous mutations and the absence of recombination are likely responsible for its unusually low genomic GC level.
CONCLUSIONS
Sd. ludwigii has followed a unique evolutionary trajectory that possibly derives fitness benefits from the combination of frequent mating between products of the same meiotic event with the extreme suppression of meiotic recombination. This life style ensures preservation of heterozygosity throughout its genome and may enable the species to adapt to its environment and survive with only minimal levels of rare meiotic recombination. We propose Sd. ludwigii as an excellent natural forum for the study of genome evolution and recombination rates.
Topics: Chromosome Segregation; Crossing Over, Genetic; Evolution, Molecular; Genome, Fungal; Loss of Heterozygosity; Meiosis; Mitosis; Mutation Rate; Recombination, Genetic; Saccharomycetales
PubMed: 34732243
DOI: 10.1186/s13059-021-02521-w -
TAG. Theoretical and Applied Genetics.... Mar 2019The crossovers (COs) that occur during meiotic recombination lead to genetic diversity upon which natural and artificial selection can act. The potential of tinkering... (Review)
Review
The crossovers (COs) that occur during meiotic recombination lead to genetic diversity upon which natural and artificial selection can act. The potential of tinkering with the mechanisms of meiotic recombination to increase the amount of genetic diversity accessible for breeders has been under the research spotlight for years. A wide variety of approaches have been proposed to increase CO frequency, alter CO distribution and induce COs between non-homologous chromosomal regions. For most of these approaches, translational biology will be crucial for demonstrating how these strategies can be of practical use in plant breeding. In this review, we describe how tinkering with meiotic recombination could benefit plant breeding and give concrete examples of how these strategies could be implemented into breeding programs.
Topics: Chromosomes, Plant; Crossing Over, Genetic; Homologous Recombination; Meiosis; Plant Breeding; Plants
PubMed: 30483818
DOI: 10.1007/s00122-018-3240-1 -
IUBMB Life Aug 2018Diploid organisms undergo meiosis to produce haploid germ cells. Crossover events during meiosis promote genetic diversity and facilitate accurate chromosome... (Review)
Review
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.
Topics: Chromosome Segregation; Genome, Fungal; High-Throughput Nucleotide Sequencing; Meiosis; Polymorphism, Single Nucleotide; Recombination, Genetic; Saccharomyces cerevisiae
PubMed: 29934971
DOI: 10.1002/iub.1877 -
DNA Research : An International Journal... Dec 2017Traditional plant breeding relies on meiotic recombination for mixing of parental alleles to create novel allele combinations. Detailed analysis of recombination...
Traditional plant breeding relies on meiotic recombination for mixing of parental alleles to create novel allele combinations. Detailed analysis of recombination patterns in model organisms shows that recombination is tightly regulated within the genome, but frequencies vary extensively along chromosomes. Despite being a model organism for fruit developmental studies, high-resolution recombination patterns are lacking in tomato. In this study, we developed a novel methodology to use low-coverage resequencing to identify genome-wide recombination patterns and applied this methodology on 60 tomato Recombinant Inbred Lines (RILs). Our methodology identifies polymorphic markers from the low-coverage resequencing population data and utilizes the same data to locate the recombination breakpoints in individuals by using a variable sliding window. We identified 1,445 recombination sites comprising 112 recombination prone regions enriched for AT-rich DNA motifs. Furthermore, the recombination prone regions in tomato preferably occurred in gene promoters over intergenic regions, an observation consistent with Arabidopsis thaliana, Zea mays and Mimulus guttatus. Overall, our cost effective method and findings enhance the understanding of meiotic recombination in tomato and suggest evolutionarily conserved recombination associated genomic features.
Topics: Genome, Plant; High-Throughput Nucleotide Sequencing; Solanum lycopersicum; Meiosis; Nucleotide Motifs; Polymorphism, Single Nucleotide; Recombination, Genetic; Sequence Analysis, DNA
PubMed: 28605512
DOI: 10.1093/dnares/dsx024 -
The American Naturalist Feb 2020Sex differences in overall recombination rates are well known, but little theoretical or empirical attention has been given to how and why sexes differ in their...
Sex differences in overall recombination rates are well known, but little theoretical or empirical attention has been given to how and why sexes differ in their recombination landscapes: the patterns of recombination along chromosomes. In the first scientific review of this phenomenon, we find that recombination is biased toward telomeres in males and more uniformly distributed in females in most vertebrates and many other eukaryotes. Notable exceptions to this pattern exist, however. Fine-scale recombination patterns also frequently differ between males and females. The molecular mechanisms responsible for sex differences remain unclear, but chromatin landscapes play a role. Why these sex differences evolve also is unclear. Hypotheses suggest that they may result from sexually antagonistic selection acting on coding genes and their regulatory elements, meiotic drive in females, selection during the haploid phase of the life cycle, selection against aneuploidy, or mechanistic constraints. No single hypothesis, however, can adequately explain the evolution of sex differences in all cases. Sex-specific recombination landscapes have important consequences for population differentiation and sex chromosome evolution.
Topics: Animals; Biological Evolution; Chromosomes; Crossing Over, Genetic; Epigenesis, Genetic; Female; Humans; Male; Meiosis; Plants; Recombination, Genetic; Sex Characteristics
PubMed: 32017625
DOI: 10.1086/704943 -
DNA Repair Apr 2019There are several DNA helicases involved in seemingly overlapping aspects of homologous and homoeologous recombination. Mutations of many of these helicases are directly... (Review)
Review
There are several DNA helicases involved in seemingly overlapping aspects of homologous and homoeologous recombination. Mutations of many of these helicases are directly implicated in genetic diseases including cancer, rapid aging, and infertility. MCM8/9 are recent additions to the catalog of helicases involved in recombination, and so far, the evidence is sparse, making assignment of function difficult. Mutations in MCM8/9 correlate principally with primary ovarian failure/insufficiency (POF/POI) and infertility indicating a meiotic defect. However, they also act when replication forks collapse/break shuttling products into mitotic recombination and several mutations are found in various somatic cancers. This review puts MCM8/9 in context with other replication and recombination helicases to narrow down its genomic maintenance role. We discuss the known structure/function relationship, the mutational spectrum, and dissect the available cellular and organismal data to better define its role in recombination.
Topics: Animals; DNA Replication; Genome; Humans; Infertility; Meiosis; Minichromosome Maintenance Proteins; Recombination, Genetic
PubMed: 30743181
DOI: 10.1016/j.dnarep.2019.02.003 -
The FEBS Journal Jul 2015During prophase of meiosis I, homologous chromosomes interact and undergo recombination. Successful completion of these processes is required in order for the homologous... (Review)
Review
During prophase of meiosis I, homologous chromosomes interact and undergo recombination. Successful completion of these processes is required in order for the homologous chromosomes to mount the meiotic spindle as a pair. The organization of the chromosomes into pairs ensures orderly segregation to opposite poles of the dividing cell, such that each gamete receives one copy of each chromosome. Chiasmata, the cytological manifestation of crossover products of recombination, physically connect the homologs in pairs, providing a linkage that facilitates their segregation. Consequently, mutations that reduce the level of recombination are invariably associated with increased errors in meiotic chromosome segregation. In this review, we focus on recent biochemical and genetic advances in elucidating the mechanisms of meiotic DNA strand exchange catalyzed by the Dmc1 protein. We also discuss the mode by which two recombination mediators, Hop2 and Mnd1, facilitate rate-limiting steps of DNA strand exchange catalyzed by Dmc1.
Topics: Animals; Cell Cycle Proteins; DNA Breaks, Double-Stranded; DNA Repair; DNA-Binding Proteins; Humans; Meiosis; Nuclear Proteins; Rad51 Recombinase; Recombination, Genetic; Trans-Activators
PubMed: 25953379
DOI: 10.1111/febs.13317