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Tunjić-Cvitanić M, García-Souto D, Pasantes JJ, Šatović-Vukšić E. Dominance of transposable element-related satDNAs results in great complexity of "satDNA library" and invokes the extension towards "repetitive DNA library". MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:236-251. [PMID: 38827134 PMCID: PMC11136912 DOI: 10.1007/s42995-024-00218-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 02/26/2024] [Indexed: 06/04/2024]
Abstract
Research on bivalves is fast-growing, including genome-wide analyses and genome sequencing. Several characteristics qualify oysters as a valuable model to explore repetitive DNA sequences and their genome organization. Here we characterize the satellitomes of five species in the family Ostreidae (Crassostrea angulata, C. virginica, C. hongkongensis, C. ariakensis, Ostrea edulis), revealing a substantial number of satellite DNAs (satDNAs) per genome (ranging between 33 and 61) and peculiarities in the composition of their satellitomes. Numerous satDNAs were either associated to or derived from transposable elements, displaying a scarcity of transposable element-unrelated satDNAs in these genomes. Due to the non-conventional satellitome constitution and dominance of Helitron-associated satDNAs, comparative satellitomics demanded more in-depth analyses than standardly employed. Comparative analyses (including C. gigas, the first bivalve species with a defined satellitome) revealed that 13 satDNAs occur in all six oyster genomes, with Cg170/HindIII satDNA being the most abundant in all of them. Evaluating the "satDNA library model" highlighted the necessity to adjust this term when studying tandem repeat evolution in organisms with such satellitomes. When repetitive sequences with potential variation in the organizational form and repeat-type affiliation are examined across related species, the introduction of the terms "TE library" and "repetitive DNA library" becomes essential. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-024-00218-0.
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Affiliation(s)
| | - Daniel García-Souto
- Genomes and Disease, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain
- Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - Juan J. Pasantes
- Centro de Investigación Mariña, Dpto de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, 36310 Vigo, Spain
| | - Eva Šatović-Vukšić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
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2
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de Oliveira AM, Souza GM, Toma GA, Dos Santos N, Dos Santos RZ, Goes CAG, Deon GA, Setti PG, Porto-Foresti F, Utsunomia R, Gunski RJ, Del Valle Garnero A, Herculano Correa de Oliveira E, Kretschmer R, Cioffi MDB. Satellite DNAs, heterochromatin, and sex chromosomes of the wattled jacana (Charadriiformes; Jacanidae): a species with highly rearranged karyotype. Genome 2024; 67:109-118. [PMID: 38316150 DOI: 10.1139/gen-2023-0082] [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] [Indexed: 02/07/2024]
Abstract
Charadriiformes, which comprises shorebirds and their relatives, is one of the most diverse avian orders, with over 390 species showing a wide range of karyotypes. Here, we isolated and characterized the whole collection of satellite DNAs (satDNAs) at both molecular and cytogenetic levels of one of its representative species, named the wattled jacana (Jacana jacana), a species that contains a typical ZZ/ZW sex chromosome system and a highly rearranged karyotype. In addition, we also investigate the in situ location of telomeric and microsatellite repeats. A small catalog of 11 satDNAs was identified that typically accumulated on microchromosomes and on the W chromosome. The latter also showed a significant accumulation of telomeric signals, being (GA)10 the only microsatellite with positive hybridization signals among all the 16 tested ones. These current findings contribute to our understanding of the genomic organization of repetitive DNAs in a bird species with high degree of chromosomal reorganization contrary to the majority of bird species that have stable karyotypes.
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Affiliation(s)
- Alan Moura de Oliveira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Guilherme Mota Souza
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Gustavo Akira Toma
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | | | | | - Geize Aparecida Deon
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Princia Grejo Setti
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | | | | | | | | | - Rafael Kretschmer
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
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Xu M, Guo H, Wang Y, Zhou B. Identification of chromosomes by fluorescence in situ hybridization in Gossypium hirsutum via developing oligonucleotide probes. Genome 2024; 67:64-77. [PMID: 37922519 DOI: 10.1139/gen-2023-0051] [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] [Indexed: 11/05/2023]
Abstract
Discrimination of chromosome is essential for chromosome manipulation or visual chromosome characterization. Oligonucleotide probes can be employed to simplify the procedures of chromosome identification in molecular cytogenetics due to its simplicity, fastness, cost-effectiveness, and high efficiency. So far, however, visual identification of cotton chromosomes remains unsolved. Here, we developed 16 oligonucleotide probes for rapid and accurate identification of chromosomes in Gossypium hirsutum: 9 probes, of which each is able to distinguish individually one pair of chromosomes, and seven probes, of which each distinguishes multiple pairs of chromosomes. Besides the identification of Chrs. A09 and D09, we first find Chr. D08, which carries both 45S and 5S rDNA sequences. Interestingly, we also find Chr. A07 has a small 45S rDNA size, suggesting that the size of this site on Chr. A07 may have reduced during evolution. By the combination of 45S and 5S rDNA sequences and oligonucleotide probes developed, 10 chromosomes (Chrs. 3-7, and 9-13) in A subgenome and 7 (Chrs. 1-2, 4-5, and 7-9) in D subgenome of cotton are able to be recognized. This study establishes cotton oligonucleotide fluorescence in situ hybridization technology for discrimination of chromosomes, which supports and guides for sequence assembling, particularly, for tandem repeat sequences in cotton.
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Affiliation(s)
- Min Xu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production co-sponsored by Jiangsu Province and Ministry of Education, Cotton Germplasm Enhancement and Application Engineering Research Center (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Haiyue Guo
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production co-sponsored by Jiangsu Province and Ministry of Education, Cotton Germplasm Enhancement and Application Engineering Research Center (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Yingying Wang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production co-sponsored by Jiangsu Province and Ministry of Education, Cotton Germplasm Enhancement and Application Engineering Research Center (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Baoliang Zhou
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production co-sponsored by Jiangsu Province and Ministry of Education, Cotton Germplasm Enhancement and Application Engineering Research Center (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
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Šatović-Vukšić E, Plohl M. Satellite DNAs-From Localized to Highly Dispersed Genome Components. Genes (Basel) 2023; 14:genes14030742. [PMID: 36981013 PMCID: PMC10048060 DOI: 10.3390/genes14030742] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
According to the established classical view, satellite DNAs are defined as abundant non-coding DNA sequences repeated in tandem that build long arrays located in heterochromatin. Advances in sequencing methodologies and development of specialized bioinformatics tools enabled defining a collection of all repetitive DNAs and satellite DNAs in a genome, the repeatome and the satellitome, respectively, as well as their reliable annotation on sequenced genomes. Supported by various non-model species included in recent studies, the patterns of satellite DNAs and satellitomes as a whole showed much more diversity and complexity than initially thought. Differences are not only in number and abundance of satellite DNAs but also in their distribution across the genome, array length, interspersion patterns, association with transposable elements, localization in heterochromatin and/or in euchromatin. In this review, we compare characteristic organizational features of satellite DNAs and satellitomes across different animal and plant species in order to summarize organizational forms and evolutionary processes that may lead to satellitomes' diversity and revisit some basic notions regarding repetitive DNA landscapes in genomes.
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Affiliation(s)
- Eva Šatović-Vukšić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Miroslav Plohl
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
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Tunjić-Cvitanić M, Pasantes JJ, García-Souto D, Cvitanić T, Plohl M, Šatović-Vukšić E. Satellitome Analysis of the Pacific Oyster Crassostrea gigas Reveals New Pattern of Satellite DNA Organization, Highly Scattered across the Genome. Int J Mol Sci 2021; 22:ijms22136798. [PMID: 34202698 PMCID: PMC8268682 DOI: 10.3390/ijms22136798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/22/2022] Open
Abstract
Several features already qualified the invasive bivalve species Crassostrea gigas as a valuable non-standard model organism in genome research. C. gigas is characterized by the low contribution of satellite DNAs (satDNAs) vs. mobile elements and has an extremely low amount of heterochromatin, predominantly built of DNA transposons. In this work, we have identified 52 satDNAs composing the satellitome of C. gigas and constituting about 6.33% of the genome. Satellitome analysis reveals unusual, highly scattered organization of relatively short satDNA arrays across the whole genome. However, peculiar chromosomal distribution and densities are specific for each satDNA. The inspection of the organizational forms of the 11 most abundant satDNAs shows association with constitutive parts of Helitron mobile elements. Nine of the inspected satDNAs are dominantly found in mobile element-associated form, two mostly appear standalone, and only one is present exclusively as Helitron-associated sequence. The Helitron-related satDNAs appear in more chromosomes than other satDNAs, indicating that these mobile elements could be leading satDNA propagation in C. gigas. No significant accumulation of satDNAs on certain chromosomal positions was detected in C. gigas, thus establishing a novel pattern of satDNA organization on the genome level.
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Affiliation(s)
- Monika Tunjić-Cvitanić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia; (M.T.-C.); (M.P.)
| | - Juan J. Pasantes
- Centro de Investigación Mariña, Universidade de Vigo, Dpto de Bioquímica, Xenética e Inmunoloxía, 36310 Vigo, Spain;
| | - Daniel García-Souto
- Genomes and Disease, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain;
- Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - Tonči Cvitanić
- Rimac Automobili d.o.o., Ljubljanska ulica 7, 10431 Sveta Nedelja, Croatia;
| | - Miroslav Plohl
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia; (M.T.-C.); (M.P.)
| | - Eva Šatović-Vukšić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia; (M.T.-C.); (M.P.)
- Correspondence:
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Zhang Y, Fan C, Chen Y, Wang RRC, Zhang X, Han F, Hu Z. Genome evolution during bread wheat formation unveiled by the distribution dynamics of SSR sequences on chromosomes using FISH. BMC Genomics 2021; 22:55. [PMID: 33446108 PMCID: PMC7809806 DOI: 10.1186/s12864-020-07364-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND During the bread wheat speciation by polyploidization, a series of genome rearrangement and sequence recombination occurred. Simple sequence repeat (SSR) sequences, predominately located in heterochromatic regions of chromosomes, are the effective marker for tracing the genomic DNA sequence variations. However, to date the distribution dynamics of SSRs on chromosomes of bread wheat and its donors, including diploid and tetraploid Triticum urartu, Aegilops speltoides, Aegilops tauschii, Triticum turgidum ssp. dicocoides, reflecting the genome evolution events during bread wheat formation had not been comprehensively investigated. RESULTS The genome evolution was studied by comprehensively comparing the distribution patterns of (AAC)n, (AAG)n, (AGC)n and (AG)n in bread wheat Triticum aestivum var. Chinese Spring and its progenitors T. urartu, A. speltoides, Ae. tauschii, wild tetroploid emmer wheat T. dicocoides, and cultivated emmer wheat T. dicoccum. Results indicated that there are specific distribution patterns in different chromosomes from different species for each SSRs. They provided efficient visible markers for identification of some individual chromosomes and SSR sequence evolution tracing from the diploid progenitors to hexaploid wheat. During wheat speciation, the SSR sequence expansion occurred predominately in the centromeric and pericentromeric regions of B genome chromosomes accompanied by little expansion and elimination on other chromosomes. This result indicated that the B genome might be more sensitive to the "genome shock" and more changeable during wheat polyplodization. CONCLUSIONS During the bread wheat evolution, SSRs including (AAC)n, (AAG)n, (AGC)n and (AG)n in B genome displayed the greatest changes (sequence expansion) especially in centromeric and pericentromeric regions during the polyploidization from Ae. speltoides S genome, the most likely donor of B genome. This work would enable a better understanding of the wheat genome formation and evolution and reinforce the viewpoint that B genome was originated from S genome.
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Affiliation(s)
- Yingxin Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.,College of Agriculture, Yangtze University, Jingzhou, 434000, Hubei, China
| | - Chengming Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yuhong Chen
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Richard R-C Wang
- United States Department of Agriculture, Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT, 84322-6300, USA
| | - Xiangqi Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zanmin Hu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China. .,College of Agriculture, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Satellite DNA-like repeats are dispersed throughout the genome of the Pacific oyster Crassostrea gigas carried by Helentron non-autonomous mobile elements. Sci Rep 2020; 10:15107. [PMID: 32934255 PMCID: PMC7492417 DOI: 10.1038/s41598-020-71886-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/11/2020] [Indexed: 01/31/2023] Open
Abstract
Satellite DNAs (satDNAs) are long arrays of tandem repeats typically located in heterochromatin and span the centromeres of eukaryotic chromosomes. Despite the wealth of knowledge about satDNAs, little is known about a fraction of short, satDNA-like arrays dispersed throughout the genome. Our survey of the Pacific oyster Crassostrea gigas sequenced genome revealed genome assembly replete with satDNA-like tandem repeats. We focused on the most abundant arrays, grouped according to sequence similarity into 13 clusters, and explored their flanking sequences. Structural analysis showed that arrays of all 13 clusters represent central repeats of 11 non-autonomous elements named Cg_HINE, which are classified into the Helentron superfamily of DNA transposons. Each of the described elements is formed by a unique combination of flanking sequences and satDNA-like central repeats, coming from one, exceptionally two clusters in a consecutive order. While some of the detected Cg_HINE elements are related according to sequence similarities in flanking and repetitive modules, others evidently arose in independent events. In addition, some of the Cg_HINE's central repeats are related to the classical C. gigas satDNA, interconnecting mobile elements and satDNAs. Genome-wide distribution of Cg_HINE implies non-autonomous Helentrons as a dynamic system prone to efficiently propagate tandem repeats in the C. gigas genome.
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Tunjić Cvitanić M, Vojvoda Zeljko T, Pasantes JJ, García-Souto D, Gržan T, Despot-Slade E, Plohl M, Šatović E. Sequence Composition Underlying Centromeric and Heterochromatic Genome Compartments of the Pacific Oyster Crassostrea gigas. Genes (Basel) 2020; 11:genes11060695. [PMID: 32599860 PMCID: PMC7348941 DOI: 10.3390/genes11060695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/10/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023] Open
Abstract
Segments of the genome enriched in repetitive sequences still present a challenge and are omitted in genome assemblies. For that reason, the exact composition of DNA sequences underlying the heterochromatic regions and the active centromeres are still unexplored for many organisms. The centromere is a crucial region of eukaryotic chromosomes responsible for the accurate segregation of genetic material. The typical landmark of centromere chromatin is the rapidly-evolving variant of the histone H3, CenH3, while DNA sequences packed in constitutive heterochromatin are associated with H3K9me3-modified histones. In the Pacific oyster Crassostrea gigas we identified its centromere histone variant, Cg-CenH3, that shows stage-specific distribution in gonadal cells. In order to investigate the DNA composition of genomic regions associated with the two specific chromatin types, we employed chromatin immunoprecipitation followed by high-throughput next-generation sequencing of the Cg-CenH3- and H3K9me3-associated sequences. CenH3-associated sequences were assigned to six groups of repetitive elements, while H3K9me3-associated-ones were assigned only to three. Those associated with CenH3 indicate the lack of uniformity in the chromosomal distribution of sequences building the centromeres, being also in the same time dispersed throughout the genome. The heterochromatin of C. gigas exhibited general paucity and limited chromosomal localization as predicted, with H3K9me3-associated sequences being predominantly constituted of DNA transposons.
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Affiliation(s)
- Monika Tunjić Cvitanić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
| | - Tanja Vojvoda Zeljko
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
| | - Juan J. Pasantes
- Departamento de Bioquímica, Xenética e Inmunoloxía, Centro de Investigación Mariña (CIM), Universidade de Vigo, 36310 Vigo, Spain; (J.J.P.); (D.G.-S.)
| | - Daniel García-Souto
- Departamento de Bioquímica, Xenética e Inmunoloxía, Centro de Investigación Mariña (CIM), Universidade de Vigo, 36310 Vigo, Spain; (J.J.P.); (D.G.-S.)
- Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, Praza do Obradoiro, 0, 15705 Santiago de Compostela, Spain
- Cancer, Ageing and Somatic Mutation, Wellcome Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Tena Gržan
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
| | - Evelin Despot-Slade
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
| | - Miroslav Plohl
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
- Correspondence: (M.P.); (E.Š.)
| | - Eva Šatović
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; (M.T.C.); (T.V.Z.); (T.G.); (E.D.-S.)
- Correspondence: (M.P.); (E.Š.)
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Cross I, Portela-Bens S, García-Angulo A, Merlo MA, Rodríguez ME, Liehr T, Rebordinos L. A preliminary integrated genetic map distinguishes every chromosome pair and locates essential genes related to abiotic adaptation of Crassostrea angulata/gigas. BMC Genet 2018; 19:104. [PMID: 30442092 PMCID: PMC6238303 DOI: 10.1186/s12863-018-0689-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 10/30/2018] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The re-sequencing of C. angulata has revealed many polymorphisms in candidate genes related to adaptation to abiotic stress that are not present in C. gigas; these genes, therefore, are probably related to the ability of this oyster to retain high concentrations of toxic heavy metals. There is, in addition, an unresolved controversy as to whether or not C. angulata and C. gigas are the same species or subspecies. Both oysters have 20 metacentric chromosomes of similar size that are morphologically indistinguishable. From a genomic perspective, as a result of the great variation and selection for heterozygotes in C. gigas, the assembly of its draft genome was difficult: it is fragmented in more than seven thousand scaffolds. RESULTS In this work sixty BAC sequences of C. gigas downloaded from NCBI were assembled in BAC-contigs and assigned to BACs that were used as probes for mFISH in C. angulata and C. gigas. In addition, probes of H3, H4 histone, 18S and 5S rDNA genes were also used. Hence we obtained markers identifying 8 out the 10 chromosomes constituting the karyotype. Chromosomes 1 and 9 can be distinguished morphologically. The bioinformatic analysis carried out with the BAC-contigs annotated 88 genes. As a result, genes associated with abiotic adaptation, such as metallothioneins, have been positioned in the genome. The gene ontology analysis has also shown many molecular functions related to metal ion binding, a phenomenon associated with detoxification processes that are characteristic in oysters. Hence the provisional integrated map obtained in this study is a useful complementary tool for the study of oyster genomes. CONCLUSIONS In this study 8 out of 10 chromosome pairs of Crassostrea angulata/gigas were identified using BAC clones as probes. As a result all chromosomes can now be distinguished. Moreover, FISH showed that H3 and H4 co-localized in two pairs of chromosomes different that those previously escribed. 88 genes were annotated in the BAC-contigs most of them related with Molecular Functions of protein binding, related to the resistance of the species to abiotic stress. An integrated genetic map anchored to the genome has been obtained in which the BAC-contigs structure were not concordant with the gene structure of the C. gigas scaffolds displayed in the Genomicus database.
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Affiliation(s)
- Ismael Cross
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - Silvia Portela-Bens
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - Aglaya García-Angulo
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - Manuel A. Merlo
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - María E. Rodríguez
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - Thomas Liehr
- Institut für Humangenetik, Universitätsklinikum Jena, 07743 Jena, Germany
| | - Laureana Rebordinos
- Area de Genética. Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. Polígono Río San Pedro, 11510 Puerto Real, Cádiz, Spain
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Zheng JS, Sun CZ, Zhang SN, Hou XL, Bonnema G. Cytogenetic Diversity of Simple Sequences Repeats in Morphotypes of Brassica rapa ssp. chinensis. FRONTIERS IN PLANT SCIENCE 2016; 7:1049. [PMID: 27507974 PMCID: PMC4961004 DOI: 10.3389/fpls.2016.01049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 07/04/2016] [Indexed: 05/29/2023]
Abstract
A significant fraction of the nuclear DNA of all eukaryotes is comprised of simple sequence repeats (SSRs). Although these sequences are widely used for studying genetic variation, linkage mapping and evolution, little attention had been paid to the chromosomal distribution and cytogenetic diversity of these sequences. In this paper, we report the distribution characterization of mono-, di-, and tri-nucleotide SSRs in Brassica rapa ssp. chinensis. Fluorescence in situ hybridization was used to characterize the cytogenetic diversity of SSRs among morphotypes of B. rapa ssp. chinensis. The proportion of different SSR motifs varied among morphotypes of B. rapa ssp. chinensis, with tri-nucleotide SSRs being more prevalent in the genome of B. rapa ssp. chinensis. We determined the chromosomal locations of mono-, di-, and tri-nucleotide repeat loci. The results showed that the chromosomal distribution of SSRs in the different morphotypes is non-random and motif-dependent, and allowed us to characterize the relative variability in terms of SSR numbers and similar chromosomal distributions in centromeric/peri-centromeric heterochromatin. The differences between SSR repeats with respect to abundance and distribution indicate that SSRs are a driving force in the genomic evolution of B. rapa species. Our results provide a comprehensive view of the SSR sequence distribution and evolution for comparison among morphotypes B. rapa ssp. chinensis.
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Affiliation(s)
- Jin-shuang Zheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Horticulture, Nanjing Agricultural University, NanjingChina
- Hebei Normal University of Science and Technology, QinhuangdaoChina
| | - Cheng-zhen Sun
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Horticulture, Nanjing Agricultural University, NanjingChina
- Hebei Normal University of Science and Technology, QinhuangdaoChina
| | - Shu-ning Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Horticulture, Nanjing Agricultural University, NanjingChina
| | - Xi-lin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Horticulture, Nanjing Agricultural University, NanjingChina
| | - Guusje Bonnema
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, WageningenNetherlands
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