1
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Clark FE, Greenberg NL, Silva DMZA, Trimm E, Skinner M, Walton RZ, Rosin LF, Lampson MA, Akera T. An egg-sabotaging mechanism drives non-Mendelian transmission in mice. Curr Biol 2024:S0960-9822(24)00901-1. [PMID: 39067449 DOI: 10.1016/j.cub.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/31/2024] [Accepted: 07/01/2024] [Indexed: 07/30/2024]
Abstract
Selfish genetic elements drive in meiosis to distort their transmission ratio and increase their representation in gametes, violating Mendel's law of segregation. The two established paradigms for meiotic drive, gamete killing and biased segregation, are fundamentally different. In gamete killing, typically observed with male meiosis, selfish elements sabotage gametes that do not contain them. By contrast, killing is predetermined in female meiosis, and selfish elements bias their segregation to the single surviving gamete (i.e., the egg in animal meiosis). Here, we show that a selfish element on mouse chromosome 2, Responder to drive 2 (R2d2), drives using a hybrid mechanism in female meiosis, incorporating elements of both killing and biased segregation. We propose that if R2d2 is destined for the polar body, it manipulates segregation to sabotage the egg by causing aneuploidy, which is subsequently lethal in the embryo, ensuring that surviving progeny preferentially contain R2d2. In heterozygous females, R2d2 orients randomly on the metaphase spindle but lags during anaphase and preferentially remains in the egg, regardless of its initial orientation. Thus, the egg genotype is either euploid with R2d2 or aneuploid with both homologs of chromosome 2, with only the former generating viable embryos. Consistent with this model, R2d2 heterozygous females produce eggs with increased aneuploidy for chromosome 2, increased embryonic lethality, and increased transmission of R2d2. In contrast to typical gamete killing of sisters produced as daughter cells in a single meiosis, R2d2 prevents production of any viable gametes from meiotic divisions in which it should have been excluded from the egg.
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Affiliation(s)
- Frances E Clark
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - Naomi L Greenberg
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - Duilio M Z A Silva
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - Emily Trimm
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Morgan Skinner
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - R Zaak Walton
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - Leah F Rosin
- Unit on Chromosome Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20894, USA
| | - Michael A Lampson
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Takashi Akera
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894, USA.
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Lacy KD, Hart T, Kronauer DJC. Co-inheritance of recombined chromatids maintains heterozygosity in a parthenogenetic ant. Nat Ecol Evol 2024:10.1038/s41559-024-02455-z. [PMID: 39014144 DOI: 10.1038/s41559-024-02455-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 05/30/2024] [Indexed: 07/18/2024]
Abstract
According to Mendel's second law, chromosomes segregate randomly in meiosis. Non-random segregation is primarily known for cases of selfish meiotic drive in females, in which particular alleles bias their own transmission into the oocyte. Here we report a rare example of unselfish meiotic drive for crossover inheritance in the clonal raider ant, Ooceraea biroi, in which both alleles are co-inherited at all loci across the entire genome. This species produces diploid offspring parthenogenetically via fusion of two haploid nuclei from the same meiosis. This process should cause rapid genotypic degeneration due to loss of heterozygosity, which results if crossover recombination is followed by random (Mendelian) segregation of chromosomes. However, by comparing whole genomes of mothers and daughters, we show that loss of heterozygosity is exceedingly rare, raising the possibility that crossovers are infrequent or absent in O. biroi meiosis. Using a combination of cytology and whole-genome sequencing, we show that crossover recombination is, in fact, common but that loss of heterozygosity is avoided because crossover products are faithfully co-inherited. This results from a programmed violation of Mendel's law of segregation, such that crossover products segregate together rather than randomly. This discovery highlights an extreme example of cellular 'memory' of crossovers, which could be a common yet cryptic feature of chromosomal segregation.
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Affiliation(s)
- Kip D Lacy
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA.
| | - Taylor Hart
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA.
- Howard Hughes Medical Institute, New York, NY, USA.
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3
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Gil J, Rosin LF, Navarrete E, Chowdhury N, Abraham S, Cornilleau G, Lei EP, Mozziconacci J, Mirny LA, Muller H, Drinnenberg IA. Unique territorial and compartmental organization of chromosomes in the holocentric silkmoth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.14.557757. [PMID: 37745315 PMCID: PMC10515926 DOI: 10.1101/2023.09.14.557757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The hallmarks of chromosome organization in multicellular eukaryotes are chromosome territories (CT), chromatin compartments, and insulated domains, including topologically associated domains (TADs). Yet, most of these elements of chromosome organization are derived from analyses of a limited set of model organisms, while large eukaryotic groups, including insects, remain mostly unexplored. Here we combine Hi-C, biophysical modeling, and microscopy to characterize the 3D genome architecture of the silkworm, Bombyx mori. In contrast to other eukaryotes, B. mori chromosomes form highly separated territories. Similar to other eukaryotes, B. mori chromosomes segregate into active A and inactive B compartments, yet unlike in vertebrate systems, contacts between euchromatic A regions appear to be a strong driver of compartmentalization. Remarkably, we also identify a third compartment, called secluded S, with a unique contact pattern. Each S region shows prominent short-range self-contacts and is remarkably devoid of contacts with the rest of the chromosome, including other S regions. Compartment S hosts a unique combination of genetic and epigenetic features, localizes towards the periphery of CTs, and shows developmental plasticity. Biophysical modeling reveals that the formation of such secluded domains requires highly localized loop extrusion within them, along with a low level of extrusion in A and B. Our Hi-C data supports predicted genome-wide and localized extrusion. Such a broad, non-uniform distribution of extruders has not been seen in other organisms. Overall, our analyses support loop extrusion in insects and highlight the evolutionary plasticity of 3D genome organization, driven by a new combination of known processes.
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4
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Hockens C, Lorenzi H, Wang TT, Lei EP, Rosin LF. Chromosome segregation during spermatogenesis occurs through a unique center-kinetic mechanism in holocentric moth species. PLoS Genet 2024; 20:e1011329. [PMID: 38913752 PMCID: PMC11226059 DOI: 10.1371/journal.pgen.1011329] [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: 10/13/2023] [Revised: 07/05/2024] [Accepted: 06/03/2024] [Indexed: 06/26/2024] Open
Abstract
Precise regulation of chromosome dynamics in the germline is essential for reproductive success across species. Yet, the mechanisms underlying meiotic chromosomal events such as homolog pairing and chromosome segregation are not fully understood in many species. Here, we employ Oligopaint DNA FISH to investigate mechanisms of meiotic homolog pairing and chromosome segregation in the holocentric pantry moth, Plodia interpunctella, and compare our findings to new and previous studies in the silkworm moth, Bombyx mori, which diverged from P. interpunctella over 100 million years ago. We find that pairing in both Bombyx and Plodia spermatogenesis is initiated at gene-rich chromosome ends. Additionally, both species form rod shaped cruciform-like bivalents at metaphase I. However, unlike the telomere-oriented chromosome segregation mechanism observed in Bombyx, Plodia can orient bivalents in multiple different ways at metaphase I. Surprisingly, in both species we find that kinetochores consistently assemble at non-telomeric loci toward the center of chromosomes regardless of where chromosome centers are located in the bivalent. Additionally, sister kinetochores do not seem to be paired in these species. Instead, four distinct kinetochores are easily observed at metaphase I. Despite this, we find clear end-on microtubule attachments and not lateral microtubule attachments co-orienting these separated kinetochores. These findings challenge the classical view of segregation where paired, poleward-facing kinetochores are required for accurate homolog separation in meiosis I. Our studies here highlight the importance of exploring fundamental processes in non-model systems, as employing novel organisms can lead to the discovery of novel biology.
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Affiliation(s)
- Clio Hockens
- Unit on Chromosome Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hernan Lorenzi
- TriLab Bioinformatics Group, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tricia T. Wang
- Unit on Chromosome Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Elissa P. Lei
- Nuclear Organization and Gene Expression Section; Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Leah F. Rosin
- Unit on Chromosome Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
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5
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Boman J, Wiklund C, Vila R, Backström N. Meiotic drive against chromosome fusions in butterfly hybrids. Chromosome Res 2024; 32:7. [PMID: 38702576 PMCID: PMC11068667 DOI: 10.1007/s10577-024-09752-0] [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: 02/02/2024] [Revised: 04/21/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Species frequently differ in the number and structure of chromosomes they harbor, but individuals that are heterozygous for chromosomal rearrangements may suffer from reduced fitness. Chromosomal rearrangements like fissions and fusions can hence serve as a mechanism for speciation between incipient lineages, but their evolution poses a paradox. How can rearrangements get fixed between populations if heterozygotes have reduced fitness? One solution is that this process predominantly occurs in small and isolated populations, where genetic drift can override natural selection. However, fixation is also more likely if a novel rearrangement is favored by a transmission bias, such as meiotic drive. Here, we investigate chromosomal transmission distortion in hybrids between two wood white (Leptidea sinapis) butterfly populations with extensive karyotype differences. Using data from two different crossing experiments, we uncover that there is a transmission bias favoring the ancestral chromosomal state for derived fusions, a result that shows that chromosome fusions actually can fix in populations despite being counteracted by meiotic drive. This means that meiotic drive not only can promote runaway chromosome number evolution and speciation, but also that it can be a conservative force acting against karyotypic change and the evolution of reproductive isolation. Based on our results, we suggest a mechanistic model for why chromosome fusion mutations may be opposed by meiotic drive and discuss factors contributing to karyotype evolution in Lepidoptera.
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Affiliation(s)
- Jesper Boman
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden.
| | - Christer Wiklund
- Department of Zoology: Division of Ecology, Stockholm University, Stockholm, Sweden
| | - Roger Vila
- Institut de Biologia Evolutiva (CSIC-Univ. Pompeu Fabra), Passeig Marítim de La Barceloneta 37-49, 08003, Barcelona, Spain
| | - Niclas Backström
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
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Clark FE, Greenberg NL, Silva DM, Trimm E, Skinner M, Walton RZ, Rosin LF, Lampson MA, Akera T. An egg sabotaging mechanism drives non-Mendelian transmission in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.22.581453. [PMID: 38903120 PMCID: PMC11188085 DOI: 10.1101/2024.02.22.581453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
During meiosis, homologous chromosomes segregate so that alleles are transmitted equally to haploid gametes, following Mendel's Law of Segregation. However, some selfish genetic elements drive in meiosis to distort the transmission ratio and increase their representation in gametes. The established paradigms for drive are fundamentally different for female vs male meiosis. In male meiosis, selfish elements typically kill gametes that do not contain them. In female meiosis, killing is predetermined, and selfish elements bias their segregation to the single surviving gamete (i.e., the egg in animal meiosis). Here we show that a selfish element on mouse chromosome 2, R2d2, drives using a hybrid mechanism in female meiosis, incorporating elements of both male and female drivers. If R2d2 is destined for the polar body, it manipulates segregation to sabotage the egg by causing aneuploidy that is subsequently lethal in the embryo, so that surviving progeny preferentially contain R2d2. In heterozygous females, R2d2 orients randomly on the metaphase spindle but lags during anaphase and preferentially remains in the egg, regardless of its initial orientation. Thus, the egg genotype is either euploid with R2d2 or aneuploid with both homologs of chromosome 2, with only the former generating viable embryos. Consistent with this model, R2d2 heterozygous females produce eggs with increased aneuploidy for chromosome 2, increased embryonic lethality, and increased transmission of R2d2. In contrast to a male meiotic driver, which kills its sister gametes produced as daughter cells in the same meiosis, R2d2 eliminates "cousins" produced from meioses in which it should have been excluded from the egg.
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Affiliation(s)
- Frances E. Clark
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
| | - Naomi L. Greenberg
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
| | - Duilio M.Z.A. Silva
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
| | - Emily Trimm
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Morgan Skinner
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
| | - R Zaak Walton
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
| | - Leah F. Rosin
- Unit on Chromosome Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20894 USA
| | - Michael A. Lampson
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Takashi Akera
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health; Bethesda, Maryland 20894, USA
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7
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Lacy KD, Hart T, Kronauer DJ. Unselfish meiotic drive maintains heterozygosity in a parthenogenetic ant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579553. [PMID: 38405725 PMCID: PMC10888755 DOI: 10.1101/2024.02.09.579553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
According to Mendel's second law, chromosomes segregate randomly in meiosis. Nonrandom segregation is primarily known for cases of selfish meiotic drive in females, in which particular alleles bias their own transmission into the oocyte1,2. Here, we report a rare example of unselfish meiotic drive for crossover inheritance in the clonal raider ant, Ooceraea biroi. This species produces diploid offspring parthenogenetically via fusion of two haploid nuclei from the same meiosis3. This process should cause rapid genotypic degeneration due to loss of heterozygosity, which results if crossover recombination is followed by random (Mendelian) segregation of chromosomes4,5. However, by comparing whole genomes of mothers and daughters, we show that loss of heterozygosity is exceedingly rare, raising the possibility that crossovers are infrequent or absent in O. biroi meiosis. Using a combination of cytology and whole genome sequencing, we show that crossover recombination is, in fact, common, but that loss of heterozygosity is avoided because crossover products are faithfully co-inherited. This results from a programmed violation of Mendel's law of segregation, such that crossover products segregate together rather than randomly. This discovery highlights an extreme example of cellular "memory" of crossovers, which could be a common yet cryptic feature of chromosomal segregation.
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Affiliation(s)
- Kip D. Lacy
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA
| | - Taylor Hart
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA
| | - Daniel J.C. Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, New York, NY, USA
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8
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Dias S, de Oliveira Bustamante F, do Vale Martins L, da Costa VA, Montenegro C, Oliveira ARDS, de Lima GS, Braz GT, Jiang J, da Costa AF, Benko-Iseppon AM, Brasileiro-Vidal AC. Translocations and inversions: major chromosomal rearrangements during Vigna (Leguminosae) evolution. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2024; 137:29. [PMID: 38261028 DOI: 10.1007/s00122-024-04546-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024]
Abstract
KEY MESSAGE Inversions and translocations are the major chromosomal rearrangements involved in Vigna subgenera evolution, being Vigna vexillata the most divergent species. Centromeric repositioning seems to be frequent within the genus. Oligonucleotide-based fluorescence in situ hybridization (Oligo-FISH) provides a powerful chromosome identification system for inferring plant chromosomal evolution. Aiming to understand macrosynteny, chromosomal diversity, and the evolution of bean species from five Vigna subgenera, we constructed cytogenetic maps for eight taxa using oligo-FISH-based chromosome identification. We used oligopainting probes from chromosomes 2 and 3 of Phaseolus vulgaris L. and two barcode probes designed from V. unguiculata (L.) Walp. genome. Additionally, we analyzed genomic blocks among the Ancestral Phaseoleae Karyotype (APK), two V. unguiculata subspecies (V. subg. Vigna), and V. angularis (Willd.) Ohwi & Ohashi (V. subg. Ceratotropis). We observed macrosynteny for chromosomes 2, 3, 4, 6, 7, 8, 9, and 10 in all investigated taxa except for V. vexillata (L.) A. Rich (V. subg. Plectrotropis), in which only chromosomes 4, 7, and 9 were unambiguously identified. Collinearity breaks involved with chromosomes 2 and 3 were revealed. We identified minor differences in the painting pattern among the subgenera, in addition to multiple intra- and interblock inversions and intrachromosomal translocations. Other rearrangements included a pericentric inversion in chromosome 4 (V. subg. Vigna), a reciprocal translocation between chromosomes 1 and 5 (V. subg. Ceratotropis), a potential deletion in chromosome 11 of V. radiata (L.) Wilczek, as well as multiple intrablock inversions and centromere repositioning via genomic blocks. Our study allowed the visualization of karyotypic patterns in each subgenus, revealing important information for understanding intrageneric karyotypic evolution, and suggesting V. vexillata as the most karyotypically divergent species.
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Affiliation(s)
- Sibelle Dias
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Fernanda de Oliveira Bustamante
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, PE, Brazil
- Universidade do Estado de Minas Gerais, Unidade Divinópolis, Divinópolis, MG, Brazil
| | - Lívia do Vale Martins
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, PE, Brazil
- Universidade Federal do Piauí, Floriano, PI, Brazil
| | | | - Claudio Montenegro
- Departamento de Botânica, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | | | - Geyse Santos de Lima
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Guilherme Tomaz Braz
- Departamento de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil
- Department of Plant Biology, Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
| | - Jiming Jiang
- Department of Plant Biology, Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
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Xiang Y, Tsuchiya D, Yu Z, Zhao X, McKinney S, Unruh J, Slaughter B, Lake CM, Hawley RS. Multiple reorganizations of the lateral elements of the synaptonemal complex facilitate homolog segregation in Bombyx mori oocytes. Curr Biol 2024; 34:352-360.e4. [PMID: 38176417 DOI: 10.1016/j.cub.2023.12.018] [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: 10/03/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 01/06/2024]
Abstract
Although Lepidopteran females build a synaptonemal complex (SC) in pachytene, homologs do not crossover, necessitating an alternative method of homolog conjunction. In Bombyx mori oocytes, the SC breaks down at the end of pachytene, and homolog associations are maintained by a large oocyte-specific structure, which we call the bivalent bridge (BB), connecting paired homologs. The BB is derived from at least some components of the SC lateral elements (LEs). It contains the HORMAD protein HOP1 and the LE protein SYCP2 and is formed by the fusion of the two LE derivatives. As diplotene progresses, the BB increases in width and acquires a layered structure with a thick band of HOP1 separating two layers of SYCP2. The HOP1 interacting protein, PCH2, joins the BB in mid-diplotene, and by late-diplotene, it lies in the middle of the HOP1 filament. This structure is maintained through metaphase I. SYCP2 and PCH2 are lost at anaphase I, and the BB no longer connects the separating homologs. However, a key component of the BB, HOP1, remains at the metaphase I plate. These changes in organization of the BB occur simultaneously with the movement of the kinetochore protein, DSN1, from within the BB at mid-diplotene to the edge of the homologs facing the poles by metaphase I. We view these data in context of models in which SC components and regulators can be repurposed to achieve different functions, a fascinating example of evolution achieving homolog conjunction in an alternative way with recycling of SC proteins.
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Affiliation(s)
- Youbin Xiang
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Dai Tsuchiya
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Zulin Yu
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Xia Zhao
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Sean McKinney
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Jay Unruh
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Brian Slaughter
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - Cathleen M Lake
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - R Scott Hawley
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, MO 66160, USA.
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10
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Poisson W, Bastien A, Gilbert I, Carrier A, Prunier J, Robert C. Cytogenetic screening of a Canadian swine breeding nucleus using a newly developed karyotyping method named oligo-banding. Genet Sel Evol 2023; 55:47. [PMID: 37430194 DOI: 10.1186/s12711-023-00819-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND The frequency of chromosomal rearrangements in Canadian breeding boars has been estimated at 0.91 to 1.64%. These abnormalities are widely recognized as a potential cause of subfertility in livestock production. Since artificial insemination is practiced in almost all intensive pig production systems, the use of elite boars carrying cytogenetic defects that have an impact on fertility can lead to major economic losses. To avoid keeping subfertile boars in artificial insemination centres and spreading chromosomal defects within populations, cytogenetic screening of boars is crucial. Different techniques are used for this purpose, but several issues are frequently encountered, i.e. environmental factors can influence the quality of results, the lack of genomic information outputted by these techniques, and the need for prior cytogenetic skills. The aim of this study was to develop a new pig karyotyping method based on fluorescent banding patterns. RESULTS The use of 207,847 specific oligonucleotides generated 96 fluorescent bands that are distributed across the 18 autosomes and the sex chromosomes. Tested alongside conventional G-banding, this oligo-banding method allowed us to identify four chromosomal translocations and a rare unbalanced chromosomal rearrangement that was not detected by conventional banding. In addition, this method allowed us to investigate chromosomal imbalance in spermatozoa. CONCLUSIONS The use of oligo-banding was found to be appropriate for detecting chromosomal aberrations in a Canadian pig nucleus and its convenient design and use make it an interesting tool for livestock karyotyping and cytogenetic studies.
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Affiliation(s)
- William Poisson
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de recherche en reproduction, développement et santé intergénérationnelle, Québec, QC, Canada
| | - Alexandre Bastien
- Plateforme d'imagerie et microscopie, Institut de biologie intégrative et des systèmes, Université Laval, Québec, QC, Canada
| | - Isabelle Gilbert
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de recherche en reproduction, développement et santé intergénérationnelle, Québec, QC, Canada
| | - Alexandra Carrier
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de recherche en reproduction, développement et santé intergénérationnelle, Québec, QC, Canada
| | - Julien Prunier
- Département de médecine moléculaire, Faculté de médecine, Université Laval, Québec, QC, Canada
| | - Claude Robert
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada.
- Centre de recherche en reproduction, développement et santé intergénérationnelle, Québec, QC, Canada.
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Gong T, McNally FJ. Caenorhabditis elegans spermatocytes can segregate achiasmate homologous chromosomes apart at higher than random frequency during meiosis I. Genetics 2023; 223:iyad021. [PMID: 36792551 PMCID: PMC10319977 DOI: 10.1093/genetics/iyad021] [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: 12/19/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Chromosome segregation errors during meiosis are the leading cause of aneuploidy. Faithful chromosome segregation during meiosis in most eukaryotes requires a crossover which provides a physical attachment holding homologs together in a "bivalent." Crossovers are critical for homologs to be properly aligned and partitioned in the first meiotic division. Without a crossover, individual homologs (univalents) might segregate randomly, resulting in aneuploid progeny. However, Caenorhabditis elegans zim-2 mutants, which have crossover defects on chromosome V, have fewer dead embryos than that expected from random segregation. This deviation from random segregation is more pronounced in zim-2 males than that in females. We found three phenomena that can explain this apparent discrepancy. First, we detected crossovers on chromosome V in both zim-2(tm574) oocytes and spermatocytes, suggesting a redundant mechanism to make up for the ZIM-2 loss. Second, after accounting for the background crossover frequency, spermatocytes produced significantly more euploid gametes than what would be expected from random segregation. Lastly, trisomy of chromosome V is viable and fertile. Together, these three phenomena allow zim-2(tm574) mutants with reduced crossovers on chromosome V to have more viable progeny. Furthermore, live imaging of meiosis in spo-11(me44) oocytes and spermatocytes, which exhibit crossover failure on all 6 chromosomes, showed 12 univalents segregating apart in roughly equal masses in a homology-independent manner, supporting the existence of a mechanism that segregates any 2 chromosomes apart.
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Affiliation(s)
- Ting Gong
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Francis J McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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12
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Poisson W, Prunier J, Carrier A, Gilbert I, Mastromonaco G, Albert V, Taillon J, Bourret V, Droit A, Côté SD, Robert C. Chromosome-level assembly of the Rangifer tarandus genome and validation of cervid and bovid evolution insights. BMC Genomics 2023; 24:142. [PMID: 36959567 PMCID: PMC10037892 DOI: 10.1186/s12864-023-09189-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 02/14/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Genome assembly into chromosomes facilitates several analyses including cytogenetics, genomics and phylogenetics. Despite rapid development in bioinformatics, however, assembly beyond scaffolds remains challenging, especially in species without closely related well-assembled and available reference genomes. So far, four draft genomes of Rangifer tarandus (caribou or reindeer, a circumpolar distributed cervid species) have been published, but none with chromosome-level assembly. This emblematic northern species is of high interest in ecological studies and conservation since most populations are declining. RESULTS We have designed specific probes based on Oligopaint FISH technology to upgrade the latest published reindeer and caribou chromosome-level genomes. Using this oligonucleotide-based method, we found six mis-assembled scaffolds and physically mapped 68 of the largest scaffolds representing 78% of the most recent R. tarandus genome assembly. Combining physical mapping and comparative genomics, it was possible to document chromosomal evolution among Cervidae and closely related bovids. CONCLUSIONS Our results provide validation for the current chromosome-level genome assembly as well as resources to use chromosome banding in studies of Rangifer tarandus.
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Affiliation(s)
- William Poisson
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle, Québec, QC, Canada
- Réseau Québécois en reproduction, QC, Saint-Hyacinthe, Canada
| | - Julien Prunier
- Département de biochimie, microbiologie et bio-informatique, Faculté des sciences et de génie, Université Laval, Québec, QC, Canada
| | - Alexandra Carrier
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle, Québec, QC, Canada
- Réseau Québécois en reproduction, QC, Saint-Hyacinthe, Canada
| | - Isabelle Gilbert
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada
- Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle, Québec, QC, Canada
- Réseau Québécois en reproduction, QC, Saint-Hyacinthe, Canada
| | | | - Vicky Albert
- Ministère des Forêts, de la Faune et des Parcs du Québec (MFFP), Québec, QC, Canada
| | - Joëlle Taillon
- Ministère des Forêts, de la Faune et des Parcs du Québec (MFFP), Québec, QC, Canada
| | - Vincent Bourret
- Ministère des Forêts, de la Faune et des Parcs du Québec (MFFP), Québec, QC, Canada
| | - Arnaud Droit
- Département de médecine moléculaire, Faculté de médecine, Université Laval, Québec, QC, Canada
| | - Steeve D Côté
- Caribou Ungava, Département de biologie and Centre d'études nordiques, Faculté des sciences et de génie, Université Laval, Québec, QC, Canada
| | - Claude Robert
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, QC, Canada.
- Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle, Québec, QC, Canada.
- Réseau Québécois en reproduction, QC, Saint-Hyacinthe, Canada.
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Munro C, Cadis H, Pagnotta S, Houliston E, Huynh JR. Conserved meiotic mechanisms in the cnidarian Clytia hemisphaerica revealed by Spo11 knockout. SCIENCE ADVANCES 2023; 9:eadd2873. [PMID: 36706182 PMCID: PMC9882977 DOI: 10.1126/sciadv.add2873] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
During meiosis, DNA recombination allows the shuffling of genetic information between the maternal and paternal chromosomes. Recombination is initiated by double-strand breaks (DSBs) catalyzed by the conserved enzyme Spo11. How this crucial event is connected to other meiotic processes is unexpectedly variable depending on the species. Here, we knocked down Spo11 by CRISPR in the jellyfish Clytia hemisphaerica. Germ cells in Clytia Spo11 mutants fail to assemble synaptonemal complexes and chiasmata, and in consequence, homologous chromosome pairs in females remain unassociated during oocyte growth and meiotic divisions, creating aneuploid but fertilizable eggs that develop into viable larvae. Clytia thus shares an ancient eukaryotic dependence of synapsis and chromosome segregation on Spo11-generated DSBs. Phylogenetically, Clytia belongs to Cnidaria, the sister clade to Bilateria where classical animal model species are found, so these results provide fresh evolutionary perspectives on meiosis regulation.
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Affiliation(s)
- Catriona Munro
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-Mer 06230, France
| | - Hugo Cadis
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-Mer 06230, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée, Université Nice Côte d’Azur, Parc Valrose, Nice 06108, France
| | - Evelyn Houliston
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Villefranche-sur-Mer 06230, France
| | - Jean-René Huynh
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
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Dosage compensation in Bombyx mori is achieved by partial repression of both Z chromosomes in males. Proc Natl Acad Sci U S A 2022; 119:e2113374119. [PMID: 35239439 PMCID: PMC8915793 DOI: 10.1073/pnas.2113374119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Genes on sex chromosomes (i.e. human chX) are regulated differently in males and females to balance gene expression levels between sexes (XY vs. XX). This sex-specific regulation is called dosage compensation (DC). DC is achieved by altering the shape and compaction of sex chromosomes specifically in one sex. In this study, we use Oligopaints to examine DC in silkworms. This study visualizes this phenomenon in a species with ZW sex chromosomes, which evolved independently of XY. Our data support a long-standing model for how DC mechanisms evolved across species, and we show potential similarity between DC in silkworms and nematodes, suggesting that this type of DC may have emerged multiple independent times throughout evolution. Interphase chromatin is organized precisely to facilitate accurate gene expression. The structure–function relationship of chromatin is epitomized in sex chromosome dosage compensation (DC), where sex-linked gene expression is balanced between males and females via sex-specific alterations to three-dimensional chromatin structure. Studies in ZW-bearing species suggest that DC is absent or incomplete in most lineages except butterflies and moths, where male (ZZ) Z chromosome (chZ) expression is reduced by half to equal females (ZW). However, whether one chZ is inactivated (as in mammals) or both are partially repressed (as in Caenorhabditis elegans) is unclear. Using Oligopaints in the silkworm, Bombyx mori, we visualize autosomes and chZ in somatic cells from both sexes. We find that B. mori chromosomes are highly compact relative to Drosophila. We show that in B. mori males, both chZs are similar in size and shape and are more compact than autosomes or the female chZ after DC establishment, suggesting both male chZs are partially and equally downregulated. We also find that in the early stages of DC in females, chZ chromatin becomes more accessible and Z-linked expression increases. Concomitant with these changes, the female chZ repositions toward the nuclear center, revealing nonsequencing-based support for Ohno’s hypothesis. These studies visualizing interphase genome organization and chZ structure in Lepidoptera uncover intriguing similarities between DC in B. mori and C. elegans, despite these lineages harboring evolutionarily distinct sex chromosomes (ZW/XY), suggesting a possible role for holocentricity in DC mechanisms.
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Mohanta TK, Mishra AK, Al-Harrasi A. The 3D Genome: From Structure to Function. Int J Mol Sci 2021; 22:11585. [PMID: 34769016 PMCID: PMC8584255 DOI: 10.3390/ijms222111585] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 01/09/2023] Open
Abstract
The genome is the most functional part of a cell, and genomic contents are organized in a compact three-dimensional (3D) structure. The genome contains millions of nucleotide bases organized in its proper frame. Rapid development in genome sequencing and advanced microscopy techniques have enabled us to understand the 3D spatial organization of the genome. Chromosome capture methods using a ligation approach and the visualization tool of a 3D genome browser have facilitated detailed exploration of the genome. Topologically associated domains (TADs), lamin-associated domains, CCCTC-binding factor domains, cohesin, and chromatin structures are the prominent identified components that encode the 3D structure of the genome. Although TADs are the major contributors to 3D genome organization, they are absent in Arabidopsis. However, a few research groups have reported the presence of TAD-like structures in the plant kingdom.
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Affiliation(s)
- Tapan Kumar Mohanta
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Oman
| | - Awdhesh Kumar Mishra
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; or
| | - Ahmed Al-Harrasi
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Oman
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