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Wang J, Wang W, Li J, Zhang Y, Luo K, Han L, Xiang C, Chai M, Luo Z, Zhao R, Liu S. Formation of the synaptonemal complex in a gynogenetic allodiploid hybrid fish. Front Genet 2023; 14:998775. [PMID: 36923790 PMCID: PMC10009232 DOI: 10.3389/fgene.2023.998775] [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: 07/20/2022] [Accepted: 02/17/2023] [Indexed: 03/03/2023] Open
Abstract
Introduction: The correct pairing and separation of homologous chromosomes during meiosis is crucial to ensure both genetic stability and genetic diversity within species. In allodiploid organisms, synapsis often fails, leading to sterility. However, a gynogenetic allodiploid hybrid clone line (GDH), derived by crossing red crucian carp (Carassius auratus ♀) and common carp (Cyprinus carpio ♂), stably produces diploid eggs. Because the GDH line carries 100 chromosomes with 50 chromosomes from the red crucian carp (RCC; ♀, 2n = 2x = 100) and 50 chromosomes from the common carp (CC; C. carpio L., ♂, 2n = 2x = 100), it is interesting to study the mechanisms of homologous chromosome pairing during meiosis in GDH individuals. Methods: By using fluorescence in situ hybridization (FISH) with a probe specific to the red crucian carp to label homologous chromosomes, we identified the synaptonemal complex via immunofluorescence assay of synaptonemal complex protein 3 (SCP3). Results: FISH results indicated that, during early ovarian development, the GDH oogonium had two sets of chromosomes with only one set from Carassius auratus, leading to the failure formation of normal bivalents and the subsequently blocking of meiosis. This inhibition lasted at least 5 months. After this long period of inhibition, pairs of germ cells fused, doubling the chromosomes such that the oocyte contained two sets of chromosomes from each parent. After chromosome doubling at 10 months old, homologous chromosomes and the synaptonemal complex were identified. Discussion: Causally, meiosis proceeded normally and eventually formed diploid germ cells. These results further clarify the mechanisms by which meiosis proceeds in hybrids.
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Affiliation(s)
- Jing Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Wen Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Jihong Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yirui Zhang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Kaikun Luo
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Linmei Han
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Caixia Xiang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Mingli Chai
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Ziye Luo
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Rurong Zhao
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
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2
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Chmielewska M, Kaźmierczak M, Rozenblut-Kościsty B, Kolenda K, Dudzik A, Dedukh D, Ogielska M. Genome elimination from the germline cells in diploid and triploid male water frogs Pelophylax esculentus. Front Cell Dev Biol 2022; 10:1008506. [PMID: 36313575 PMCID: PMC9615423 DOI: 10.3389/fcell.2022.1008506] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
Hybridogenesis is a hemiclonal reproductive strategy in diploid and triploid hybrids. Our study model is a frog P. esculentus (diploid RL and triploids RLL and RRL), a natural hybrid between P. lessonae (LL) and P. ridibundus (RR). Hybridogenesis relies on elimination of one genome (L or R) from gonocytes (G) in tadpole gonads during prespermatogenesis, but not from spermatogonial stem cells (SSCs) in adults. Here we provide the first comprehensive study of testis morphology combined with chromosome composition in the full spectrum of spermatogenic cells. Using genomic in situ hybridization (GISH) and FISH we determined genomes in metaphase plates and interphase nuclei in Gs and SSCs. We traced genomic composition of SSCs, spermatocytes and spermatozoa in individual adult males that were crossed with females of the parental species and gave progeny. Degenerating gonocytes (24%–39%) and SSCs (18%–20%) led to partial sterility of juvenile and adult gonads. We conclude that elimination and endoreplication not properly completed during prespermatogenesis may be halted when gonocytes become dormant in juveniles. After resumption of mitotic divisions by SSCs in adults, these 20% of cells with successful genome elimination and endoreplication continue spermatogenesis, while in about 80% spermatogenesis is deficient. Majority of abnormal cells are eliminated by cell death, however some of them give rise to aneuploid spermatocytes and spermatozoa which shows that hybridogenesis is a wasteful process.
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Affiliation(s)
- Magdalena Chmielewska
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
- *Correspondence: Magdalena Chmielewska,
| | - Mikołaj Kaźmierczak
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
- Department of Medicine Biology, The Cardinal Wyszyński National Institute of Cardiology, Warsaw, Poland
| | - Beata Rozenblut-Kościsty
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
| | - Krzysztof Kolenda
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
| | - Anna Dudzik
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
| | - Dmitrij Dedukh
- Laboratory of Non-Mendelian Evolution, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Maria Ogielska
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Wrocław, Poland
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Matson MEH, Liang Q, Lonardi S, Judelson HS. Karyotype variation, spontaneous genome rearrangements affecting chemical insensitivity, and expression level polymorphisms in the plant pathogen Phytophthora infestans revealed using its first chromosome-scale assembly. PLoS Pathog 2022; 18:e1010869. [PMID: 36215336 PMCID: PMC9584435 DOI: 10.1371/journal.ppat.1010869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/20/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Natural isolates of the potato and tomato pathogen Phytophthora infestans exhibit substantial variation in virulence, chemical sensitivity, ploidy, and other traits. A chromosome-scale assembly was developed to expand genomic resources for this oomyceteous microbe, and used to explore the basis of variation. Using PacBio and Illumina data, a long-range linking library, and an optical map, an assembly was created and coalesced into 15 pseudochromosomes spanning 219 Mb using SNP-based genetic linkage data. De novo gene prediction combined with transcript evidence identified 19,981 protein-coding genes, plus about eight thousand tRNA genes. The chromosomes were comprised of a mosaic of gene-rich and gene-sparse regions plus very long centromeres. Genes exhibited a biased distribution across chromosomes, especially members of families encoding RXLR and CRN effectors which clustered on certain chromosomes. Strikingly, half of F1 progeny of diploid parents were polyploid or aneuploid. Substantial expression level polymorphisms between strains were identified, much of which could be attributed to differences in chromosome dosage, transposable element insertions, and adjacency to repetitive DNA. QTL analysis identified a locus on the right arm of chromosome 3 governing sensitivity to the crop protection chemical metalaxyl. Strains heterozygous for resistance often experienced megabase-sized deletions of that part of the chromosome when cultured on metalaxyl, increasing resistance due to loss of the sensitive allele. This study sheds light on diverse phenomena affecting variation in P. infestans and relatives, helps explain the prevalence of polyploidy in natural populations, and provides a new foundation for biologic and genetic investigations.
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Affiliation(s)
- Michael E. H. Matson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, United States of America
| | - Qihua Liang
- Department of Computer Science and Engineering, University of California, Riverside, California, United States of America
| | - Stefano Lonardi
- Department of Computer Science and Engineering, University of California, Riverside, California, United States of America
| | - Howard S. Judelson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, United States of America
- * E-mail:
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Tichopád T, Franěk R, Doležálková-Kaštánková M, Dedukh D, Marta A, Halačka K, Steinbach C, Janko K, Pšenička M. Clonal gametogenesis is triggered by intrinsic stimuli in the hybrid's germ cells but is dependent on sex differentiation. Biol Reprod 2022; 107:446-457. [PMID: 35416937 DOI: 10.1093/biolre/ioac074] [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: 12/08/2021] [Revised: 03/08/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Interspecific hybridization may trigger the transition from sexual reproduction to asexuality, but mechanistic reasons for such a change in a hybrid's reproduction are poorly understood. Gametogenesis of many asexual hybrids involves a stage of premeiotic endoreduplication (PMER), when gonial cells duplicate chromosomes and subsequent meiotic divisions involve bivalents between identical copies, leading to production of clonal gametes. Here, we investigated the triggers of PMER and whether its induction is linked to intrinsic stimuli within a hybrid's gonial cells or whether it is regulated by the surrounding gonadal tissue. We investigated gametogenesis in the Cobitis taenia hybrid complex, which involves sexually reproducing species (Cobitis elongatoides and C. taenia) as well as their hybrids, where females reproduce clonally via PMER while males are sterile. We transplanted spermatogonial stem cells (SSCs) from C. elongatoides and triploid hybrid males into embryos of sexual species and of asexual hybrid females, respectively, and observed their development in an allospecific gonadal environment. Sexual SSCs underwent regular meiosis and produced normally reduced gametes when transplanted into clonal females. On the other hand, the hybrid's SSCs lead to sterility when transplanted into sexual males, but maintained their ability to undergo asexual development (PMER) and production of clonal eggs, when transplanted into sexual females. This suggests that asexual gametogenesis is under complex control when somatic gonadal tissue indirectly affects the execution of asexual development by determining the sexual differentiation of stem cells and once such cells develop to female phenotypes, hybrid germ cells trigger the PMER from their intrinsic signals.
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Affiliation(s)
- Tomáš Tichopád
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25 Vodňany, Czech Republic
| | - Roman Franěk
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25 Vodňany, Czech Republic
| | - Marie Doležálková-Kaštánková
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic
| | - Dmitrij Dedukh
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic
| | - Anatolie Marta
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.,Department of Zoology, Faculty of Science, Charles University in Prague, 128 00 Prague, Czech Republic.,Institute of Zoology, Academy of Science of Moldova, MD-2028, Academiei 1, 2001 Chisinau, Moldova
| | - Karel Halačka
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.,Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Květná 8, 603 65 Brno, Czech Republic
| | - Christoph Steinbach
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25 Vodňany, Czech Republic
| | - Karel Janko
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.,Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Martin Pšenička
- University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25 Vodňany, Czech Republic
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5
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Zadesenets KS, Jetybayev IY, Schärer L, Rubtsov NB. Genome and Karyotype Reorganization after Whole Genome Duplication in Free-Living Flatworms of the Genus Macrostomum. Int J Mol Sci 2020; 21:E680. [PMID: 31968653 PMCID: PMC7013459 DOI: 10.3390/ijms21020680] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/09/2020] [Indexed: 01/31/2023] Open
Abstract
The genus Macrostomum represents a diverse group of rhabditophoran flatworms with >200 species occurring around the world. Earlier we uncovered karyotype instability linked to hidden polyploidy in both M. lignano (2n = 8) and its sibling species M. janickei (2n = 10), prompting interest in the karyotype organization of close relatives. In this study, we investigated chromosome organization in two recently described and closely related Macrostomum species, M. mirumnovem and M. cliftonensis, and explored karyotype instability in laboratory lines and cultures of M. lignano (DV1/10, 2n = 10) and M. janickei in more detail. We revealed that three of the four studied species are characterized by karyotype instability, while M. cliftonensis showed a stable 2n = 6 karyotype. Next, we performed comparative cytogenetics of these species using fluorescent in situ hybridization (FISH) with a set of DNA probes (including microdissected DNA probes generated from M. lignano chromosomes, rDNA, and telomeric DNA). To explore the chromosome organization of the unusual 2n = 9 karyotype discovered in M. mirumnovem, we then generated chromosome-specific DNA probes for all chromosomes of this species. Similar to M. lignano and M. janickei, our findings suggest that M. mirumnovem arose via whole genome duplication (WGD) followed by considerable chromosome reshuffling. We discuss possible evolutionary scenarios for the emergence and reorganization of the karyotypes of these Macrostomum species and consider their suitability as promising animal models for studying the mechanisms and regularities of karyotype and genome evolution after a recent WGD.
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Affiliation(s)
- Kira S. Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave. 10, 630090 Novosibirsk, Russia;
| | - Ilyas Y. Jetybayev
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave. 10, 630090 Novosibirsk, Russia;
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, CH-4051 Basel, Switzerland;
| | - Nikolay B. Rubtsov
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave. 10, 630090 Novosibirsk, Russia;
- Department of Cytology and Genetics, Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk, Russia
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6
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Establishment and application of distant hybridization technology in fish. SCIENCE CHINA-LIFE SCIENCES 2018; 62:22-45. [DOI: 10.1007/s11427-018-9408-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022]
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7
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Zhou R, Shang R, Gong D, Xu X, Liu S. Characterization of H3 methylation in regulating oocyte development in cyprinid fish. SCIENCE CHINA-LIFE SCIENCES 2018; 62:829-837. [PMID: 30443860 DOI: 10.1007/s11427-018-9346-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/22/2018] [Indexed: 12/13/2022]
Abstract
Histone post-modifications are important epigenetic markers involved in multiple cellular processes via regulation of gene transcription or remodeling of chromatin structure. Oocyte development is a critical process under rigorous control to prevent the generation of aberrant gametes. However, the regulatory mechanism of oocyte early development is not well-understood due to the tiny size and poor distinguishability of the gonad in juvenile stages. Here, two cyprinid hybrid fishes, a sterile allotriploid fish and a gynogenetic hybrid fish with delayed oocyte development, provided research models to investigate the mechanisms involved. We used cytogenetic and molecular methods to confirm the pachytene arrest of oocytes in allotriploid fish and gynogenetic hybrid fish. On the basis of these developmental differences, we screened 21 different histone H3 modifications by ELISA and found that four modifications (H3K4me3, H3K9me3, H3K79me, and H3K79me3) differed significantly in the two cyprinid hybrid fishes. Changes in histone methylation at the three residues (H3K4, K9, K79) were caused by specific methyltransferases and demethylases. Our results provide new insights into the epigenetic regulation of oocyte early development in fish, a process critical for understanding of reproductive biology and with practical applications in the aquacultural breeding industry.
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Affiliation(s)
- Rong Zhou
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410008, China
| | - Rujie Shang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410008, China
| | - Dingbin Gong
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410008, China
| | - Xiujuan Xu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410008, China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410008, China.
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Ren L, Cui J, Wang J, Tan H, Li W, Tang C, Qin Q, Liu S. Analyzing homoeolog expression provides insights into the rediploidization event in gynogenetic hybrids of Carassius auratus red var. × Cyprinus carpio. Sci Rep 2017; 7:13679. [PMID: 29057976 PMCID: PMC5651915 DOI: 10.1038/s41598-017-14084-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 09/18/2017] [Indexed: 11/28/2022] Open
Abstract
Rediploidization is considered to be a part of the evolutionary history of allotetraploids, and resulted in the emergence of novel epigenetic regulatory activities. To study the changing patterns of gene expression following the reduction of a genome by 50%, we used RNA-seq and quantitative real-time PCR (qPCR) to investigate total gene expression and homoeolog expression in three hybrids of a C. auratus red var. (2n = 100, ♀) (R) and C. carpio (2n = 100, ♂) (C) (i.e., F1, F18, and G4) and their original parents. A comparison of homoeolog expression between G4 and F18 identified 7 genes (0.22%) that exhibited novel R/C homoeolog expression patterns in G4, while 4 genes (0.12%) were affected by R/C homoeolog silencing. We determined the direction and extent of the homoeolog expression bias (HEB). The C-HEB genes (i.e., nrp1a and igf1) and R-HEB genes (i.e., fgf23 and esm1) provided insights into the effects of the dominance of one parental homoeolog expression on growth regulation. This dominance may contribute to the rapid growth of G4 fish. Our findings may be relevant for clarifying the relationship between growth heterosis and differences in homoeolog expression patterns.
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Affiliation(s)
- Li Ren
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Jialin Cui
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Jing Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Hui Tan
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Wuhui Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Chenchen Tang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Qinbo Qin
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Shaojun Liu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, Hunan, China.
- College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China.
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Zadesenets KS, Schärer L, Rubtsov NB. New insights into the karyotype evolution of the free-living flatworm Macrostomum lignano (Platyhelminthes, Turbellaria). Sci Rep 2017; 7:6066. [PMID: 28729552 PMCID: PMC5519732 DOI: 10.1038/s41598-017-06498-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/13/2017] [Indexed: 01/02/2023] Open
Abstract
The free-living flatworm Macrostomum lignano is a model organism for evolutionary and developmental biology studies. Recently, an unusual karyotypic diversity was revealed in this species. Specifically, worms are either ‘normal’ 2n = 8, or they are aneuploid with one or two additional large chromosome(s) (i.e. 2n = 9 or 2n = 10, respectively). Aneuploid worms did not show visible behavioral or morphological abnormalities and were successful in reproduction. In this study, we generated microdissected DNA probes from chromosome 1 (further called MLI1), chromosome 2 (MLI2), and a pair of similar-sized smaller chromosomes (MLI3, MLI4). FISH using these probes revealed that MLI1 consists of contiguous regions homologous to MLI2-MLI4, suggesting that MLI1 arose due to the whole genome duplication and subsequent fusion of one full chromosome set into one large metacentric chromosome. Therefore, one presumably full haploid genome was packed into MLI1, leading to hidden tetraploidy in the M. lignano genome. The study of Macrostomum sp. 8 — a sibling species of M. lignano — revealed that it usually has one additional pair of large chromosomes (2n = 10) showing a high homology to MLI1, thus suggesting hidden hexaploidy in its genome. Possible evolutionary scenarios for the emergence of the M. lignano and Macrostomum sp. 8 genomes are discussed.
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Affiliation(s)
- Kira S Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave., 10, Novosibirsk, 630090, Russian Federation.
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, CH-4051, Switzerland
| | - Nikolay B Rubtsov
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave., 10, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Pirogova str., 2, Novosibirsk, 630090, Russian Federation
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