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Biscotti MA, Barucca M, Canapa A. New insights into the genome repetitive fraction of the Antarctic bivalve Adamussium colbecki. PLoS One 2018; 13:e0194502. [PMID: 29590185 PMCID: PMC5874043 DOI: 10.1371/journal.pone.0194502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/05/2018] [Indexed: 11/29/2022] Open
Abstract
Repetitive DNA represents the major component of the genome in both plant and animal species. It includes transposable elements (TEs), which are dispersed throughout the genome, and satellite DNAs (satDNAs), which are tandemly organized in long arrays. The study of the structure and organization of repetitive DNA contributes to our understanding of genome architecture and the mechanisms leading to its evolution. Molluscs represent one of the largest groups of invertebrates and include organisms with a wide variety of morphologies and lifestyles. To increase our knowledge of bivalves at the genome level, we analysed the Antarctic scallop Adamussium colbecki. The screening of the genomic library evidenced the presence of two novel satDNA elements and the CvA transposon. The interspecific investigation performed in this study demonstrated that one of the two satDNAs isolated in A. colbecki is widespread in polar molluscan species, indicating a possible link between repetitive DNA and abiotic factors. Moreover, the transcriptional activity of CvA and its presence in long-diverged bivalves suggests a possible role for this ancient element in shaping the genome architecture of this clade.
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Affiliation(s)
- Maria Assunta Biscotti
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
| | - Marco Barucca
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
| | - Adriana Canapa
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
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Šatović E, Vojvoda Zeljko T, Plohl M. Characteristics and evolution of satellite DNA sequences in bivalve mollusks. THE EUROPEAN ZOOLOGICAL JOURNAL 2018. [DOI: 10.1080/24750263.2018.1443164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Affiliation(s)
- E. Šatović
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - T. Vojvoda Zeljko
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - M. Plohl
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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García-Souto D, Mravinac B, Šatović E, Plohl M, Morán P, Pasantes JJ. Methylation profile of a satellite DNA constituting the intercalary G+C-rich heterochromatin of the cut trough shell Spisula subtruncata (Bivalvia, Mactridae). Sci Rep 2017; 7:6930. [PMID: 28761142 PMCID: PMC5537241 DOI: 10.1038/s41598-017-07231-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/23/2017] [Indexed: 12/30/2022] Open
Abstract
Tandemly repeated DNAs usually constitute significant portions of eukaryotic genomes. In bivalves, however, repetitive DNAs are habitually not widespread. In our search for abundant repetitive DNAs in trough shells, we discovered a novel satellite DNA, SSUsat, which constitutes at least 1.3% of the genome of Spisula subtruncata. As foreseen by the satellite DNA library hypothesis, we confirmed that this satellite DNA is also present in two other Mactridae species, showing a highly conserved nucleotide sequence together with a dramatic diminution in the number of repeats. Predominantly located at the G + C-rich intercalary heterochromatin of S. subtruncata, SSUsat displays several DNA methylation peculiarities. The level of methylation of SSUsat is high (3.38%) in comparison with bivalve standards and triplicates the mean of the S. subtruncata genome (1.13%). Methylation affects not only the cytosines in CpG dinucleotides but also those in CHH and CHG trinucleotides, a feature common in plants but scarce and without any clear known relevance in animals. SSUsat segments enriched in methylated cytosines partly overlap those showing higher sequence conservation. The presence of a chromosome pair showing an accumulation of markedly under-methylated SSUsat monomers additionally indicates that the methylation processes that shape repetitive genome compartments are quite complex.
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Affiliation(s)
- Daniel García-Souto
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, E-36310, Vigo, Spain
| | - Brankica Mravinac
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Eva Šatović
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Miroslav Plohl
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Paloma Morán
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, E-36310, Vigo, Spain
| | - Juan J Pasantes
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, E-36310, Vigo, Spain.
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Graziano S, Gullì M, Marmiroli N. Development and validation of a SYBR-Green I Real-Time PCR test to detect bivalves includingMytilusspecies in foods. Int J Food Sci Technol 2017. [DOI: 10.1111/ijfs.13429] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sara Graziano
- Dipartimento di Bioscienze; Università degli Studi di Parma; Parco Area delle Scienze 11a Parma 43124 Italy
| | - Mariolina Gullì
- Dipartimento di Bioscienze; Università degli Studi di Parma; Parco Area delle Scienze 11a Parma 43124 Italy
- Centro Interdipartimentale SITEIA.PARMA; Università degli Studi di Parma; Parco Area delle Scienze 181/A Parma 43124 Italy
| | - Nelson Marmiroli
- Dipartimento di Bioscienze; Università degli Studi di Parma; Parco Area delle Scienze 11a Parma 43124 Italy
- Centro Interdipartimentale SITEIA.PARMA; Università degli Studi di Parma; Parco Area delle Scienze 181/A Parma 43124 Italy
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A novel satellite DNA isolated in Pecten jacobaeus shows high sequence similarity among molluscs. Mol Genet Genomics 2015; 290:1717-25. [PMID: 25832354 DOI: 10.1007/s00438-015-1036-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/24/2015] [Indexed: 12/25/2022]
Abstract
The aim of this work is to investigate the sequence conservation and the evolution of repeated DNA in related species. Satellite DNA is a component of eukaryotic genomes and is made up of tandemly repeated sequences. These sequences are affected by high rates of mutation that lead to the occurrence of species-specific satellite DNAs, which are different in terms of both quantity and quality. In this work, a novel repetitive DNA family, named PjHhaI sat, is described in Pecten jacobaeus. The quantitative analyses revealed a different abundance of this element in the molluscan species investigated in agreement with the "library hypothesis" even if, in this case, at a high taxonomic level. In addition, the qualitative analysis demonstrated an astonishing sequence conservation not only among scallops but also in six other molluscan species belonging to three classes. These findings suggest that the PjHhaI sat may be considered as the most ancients of DNA described so far, which remained "frozen" during molluscan evolution. The widespread distribution of this sat DNA in molluscs as well as its long evolutionary preservation open up questions on the functional role of this element. A future challenge might be the identification of proteins or molecules which interact with the PjHhaI sat.
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Biscotti MA, Canapa A, Capriglione T, Forconi M, Odierna G, Olmo E, Petraccioli A, Barucca M. Novel repeated DNAs in the antarctic polyplacophoran Nuttallochiton mirandus (Thiele, 1906). Cytogenet Genome Res 2015; 144:212-9. [PMID: 25592394 DOI: 10.1159/000370054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2014] [Indexed: 11/19/2022] Open
Abstract
Within the scope of a project on the characterization of satellite DNAs in polar mollusks, the Antarctic chiton Nuttallochitonmirandus (Thiele, 1906) was analyzed. Two novel families of tandemly repeated DNAs, namely NmH and NmP, are described in their structure and chromosomal localization, and, furthermore, their presence was analyzed in related species. Data reported here display a particular variability in the structural organization of DNA satellites within this species. Processes driving satellite evolution, which are likely responsible for the intriguing variability of the identified satellite DNAs, are discussed.
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Affiliation(s)
- Maria A Biscotti
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
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López-Flores I, Ruiz-Rejón C, Cross I, Rebordinos L, Robles F, Navajas-Pérez R, de la Herrán R. Molecular characterization and evolution of an interspersed repetitive DNA family of oysters. Genetica 2010; 138:1211-9. [PMID: 21072565 DOI: 10.1007/s10709-010-9517-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 10/26/2010] [Indexed: 10/18/2022]
Abstract
When genomic DNA from the European flat oyster Ostrea edulis L. was digested by BclI enzyme, a band of about 150 bp was observed in agarose gel. After cloning and sequencing this band and analysing their molecular characteristics and genomic organization by means of Southern blot, in situ hybridisation, and polymerase chain reaction (PCR) protocols, we concluded that this band is an interspersed highly repeated DNA element, which is related in sequence to the flanking regions of (CT)-microsatellite loci of the species O. edulis and Crassostrea gigas. Furthermore, we determined that this element forms part of a longer repetitive unit of 268 bp in length that, at least in some loci, is present in more than one copy. By Southern blot hybridisation and PCR amplifications-using primers designed for conserved regions of the 150-bp BclI clones of O. edulis-we determined that this repetitive DNA family is conserved in five other oyster species (O. stentina, C. angulata, C. gigas, C. ariakensis, and C. sikamea) while it is apparently absent in C. gasar. Finally, based on the analysis of the repetitive units in these oyster species, we discuss the slow degree of concerted evolution in this interspersed repetitive DNA family and its use for phylogenetic analysis.
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Affiliation(s)
- Inmaculada López-Flores
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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Rasmussen RS, Morrissey MT. Application of DNA-Based Methods to Identify Fish and Seafood Substitution on the Commercial Market. Compr Rev Food Sci Food Saf 2009. [DOI: 10.1111/j.1541-4337.2009.00073.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Venier P, De Pittà C, Bernante F, Varotto L, De Nardi B, Bovo G, Roch P, Novoa B, Figueras A, Pallavicini A, Lanfranchi G. MytiBase: a knowledgebase of mussel (M. galloprovincialis) transcribed sequences. BMC Genomics 2009; 10:72. [PMID: 19203376 PMCID: PMC2657158 DOI: 10.1186/1471-2164-10-72] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 02/09/2009] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although bivalves are among the most studied marine organisms due to their ecological role, economic importance and use in pollution biomonitoring, very little information is available on the genome sequences of mussels. This study reports the functional analysis of a large-scale Expressed Sequence Tag (EST) sequencing from different tissues of Mytilus galloprovincialis (the Mediterranean mussel) challenged with toxic pollutants, temperature and potentially pathogenic bacteria. RESULTS We have constructed and sequenced seventeen cDNA libraries from different Mediterranean mussel tissues: gills, digestive gland, foot, anterior and posterior adductor muscle, mantle and haemocytes. A total of 24,939 clones were sequenced from these libraries generating 18,788 high-quality ESTs which were assembled into 2,446 overlapping clusters and 4,666 singletons resulting in a total of 7,112 non-redundant sequences. In particular, a high-quality normalized cDNA library (Nor01) was constructed as determined by the high rate of gene discovery (65.6%). Bioinformatic screening of the non-redundant M. galloprovincialis sequences identified 159 microsatellite-containing ESTs. Clusters, consensuses, related similarities and gene ontology searches have been organized in a dedicated, searchable database http://mussel.cribi.unipd.it. CONCLUSION We defined the first species-specific catalogue of M. galloprovincialis ESTs including 7,112 unique transcribed sequences. Putative microsatellite markers were identified. This annotated catalogue represents a valuable platform for expression studies, marker validation and genetic linkage analysis for investigations in the biology of Mediterranean mussels.
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Affiliation(s)
- Paola Venier
- Department of Biology, University of Padova, Via U Bassi 58/B, Padova, Italy.
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Biscotti MA, Barucca M, Capriglione T, Odierna G, Olmo E, Canapa A. Molecular and cytogenetic characterization of repetitive DNA in the Antarctic polyplacophoran Nuttallochiton mirandus. Chromosome Res 2008; 16:907-16. [PMID: 18679814 DOI: 10.1007/s10577-008-1248-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 06/09/2008] [Accepted: 06/09/2008] [Indexed: 01/11/2023]
Abstract
Two highly repeated DNAs, designated NmE1/NmE2 and NmE5, were identified by EcoRV digestion in the chiton Nuttallochiton mirandus (Mollusca: Polyplacophora). The comparison of the sequences obtained showed high similarity in 5' and 3' regions and the NmE5 sequence displayed an inserted sequence that might arise from a transposable element. Southern blotting analyses suggested a tandem organization of both satellite DNA families identified. Moreover, dot blot analyses, performed on several molluscan species, revealed a different degree of conservation of the repeated DNAs. Fluorescence in-situ hybridizations (FISH) on metaphase chromosomes showed that both satellite DNAs are located at centromeric regions.
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Affiliation(s)
- Maria Assunta Biscotti
- Istituto di Biologia e Genetica, Facoltà di Scienze, Università Politecnica delle Marche, via Brecce Bianche, I-60131, Ancona, Italy
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12
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Zhang L, Chen C, Cheng J, Wang S, Hu X, Hu J, Bao Z. Initial analysis of tandemly repetitive sequences in the genome of Zhikong scallop (Chlamys farreri Jones et Preston). DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2007; 19:195-205. [PMID: 17852361 DOI: 10.1080/10425170701462316] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Tandemly repetitive sequences are widespread in all eukaryotic genomes, but data on tandem repeats are limited in Zhikong scallop (Chlamys farreri). In the present study, paired-end sequencing of 2016 individual fosmid clones resulted in 3646 sequences. A total of 2,286,986 bp of genomic sequences were generated, representing approximately 1.84 per thousand of the Zhikong scallop genome. Using tandem repeats finder (TRF) software, a total of 2500 tandem repeats were found, including 313 satellites, 1816 minisatellites and 371 microsatellites. The cumulative length of tandem repeats was 552,558 bp, accounting for 24.16% of total length. Specifically, the length of microsatellites, minisatellites and satellites was 9425, 336,001 and 207,132 bp, accounting for 1.71, 60.81 and 37.49% of the length of tandem repeats, and 0.41, 14.69 and 9.06% of total length, respectively. The detailed information on the characteristic of all repeat units was also represented, which will provide a useful resource for physical mapping and better utilization of the existing genomic information in Zhikong scallop.
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Affiliation(s)
- Lingling Zhang
- Division of Life Science and Technology, Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao, People's Republic of China.
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13
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Biscotti MA, Canapa A, Olmo E, Barucca M, Teo CH, Schwarzacher T, Dennerlein S, Richter R, Heslop-Harrison JSP. Repetitive DNA, molecular cytogenetics and genome organization in the King scallop (Pecten maximus). Gene 2007; 406:91-8. [PMID: 17706376 DOI: 10.1016/j.gene.2007.06.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 06/15/2007] [Accepted: 06/25/2007] [Indexed: 11/26/2022]
Abstract
We studied the structure, organization and relationship of repetitive DNA sequences in the genome of the scallop, Pecten maximus, a bivalve that is important both commercially and in marine ecology. Recombinant DNA libraries were constructed after partial digestion of genomic DNA from scallop with PstI and ApaI restriction enzymes. Clones containing repetitive DNA were selected by hybridisation to labelled DNA from scallop, oyster and mussel; colonies showing strong hybridisation only to scallop were selected for analysis and sequencing. Six non-homologous tandemly repeated sequences were identified in the sequences, and Southern hybridisation with all repeat families to genomic DNA digests showed characteristic ladders of hybridised bands. Three families had monomer lengths around 40 bp while three had repeats characteristic of the length wrapping around one (170 bp), or two (326 bp) nucleosomes. In situ hybridisation to interphase nuclei showed each family had characteristic numbers of clusters indicating contrasting arrangements. Two of the repeats had unusual repetitions of bases within their sequence, which may relate to the nature of microsatellites reported in bivalves. The study of these rapidly evolving sequences is valuable to understand an important source of genomic diversity, has the potential to provide useful markers for population studies and gives a route to identify mechanisms of DNA sequence evolution.
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14
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Rodakis GC, Cao L, Mizi A, Kenchington ELR, Zouros E. Nucleotide Content Gradients in Maternally and Paternally Inherited Mitochondrial Genomes of the Mussel Mytilus. J Mol Evol 2007; 65:124-36. [PMID: 17632681 DOI: 10.1007/s00239-005-0298-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Accepted: 07/26/2006] [Indexed: 10/23/2022]
Abstract
Several studies have shown that in vertebrate mtDNAs the nucleotide content at fourfold degenerate sites is well correlated with the site's time of exposure to the single-strand state, as predicted from the asymmetrical model of mtDNA replication. Here we examine whether the same explanation may hold for the regional variation in nucleotide content in the maternal and paternal mtDNAs of the mussel Mytilus galloprovincialis. The origin of replication of the heavy strand (O(H)) of these genomes has been previously established. A systematic search of the two genomes for sequences that are likely to act as the origin of replication of the light strand (O(L)) suggested that the most probable site lies within the ND3 gene. By adopting this O(L) position we calculated times of exposure for 0(FD) (nondegenerate), 2(FD) (twofold degenerate), and 4(FD) (fourfold degenerate) sites of the protein-coding part of the genome and for the rRNA, tRNA and noncoding parts. The presence of thymine and absence of guanine at 4(FD) sites was highly correlated with the presumed time of exposure. Such an effect was not found for the 2(FD) sites, the rRNA, the tRNA, or the noncoding parts. There was a trend for a small increase in cytosine at 0(FD) sites with exposure time, which is explicable as the result of biased usage of 4(FD) codons. The same analysis was applied to a recently sequenced mitochondrial genome of Mytilus trossulus and produced similar results. These results are consistent with the asymmetrical model of replication and suggest that guanine oxidation due to single-strand exposure is the main cause of regional variation of nucleotide content in Mytilus mitochondrial genomes.
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Affiliation(s)
- George C Rodakis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15701 Athens, Greece
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Kourtidis A, Drosopoulou E, Pantzartzi CN, Chintiroglou CC, Scouras ZG. Three new satellite sequences and a mobile element found inside HSP70 introns of the Mediterranean mussel (Mytilus galloprovincialis). Genome 2007; 49:1451-8. [PMID: 17426760 DOI: 10.1139/g06-111] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report the characterization of 3 new repetitive sequences from the bivalve mollusc Mytilus galloprovincialis, designated Mg1, Mg2, and Mg3, with monomer lengths of 169, 260, and 70 bp, respectively. The 3 repeats together constitute approximately 7.8% of the M. galloprovincialis genome and were found, together with ApaI-type 2 repeats, inside the introns of 2 genes of the HSP70 family, hsc70 and hsc71. Both the monomer length and the genomic content of the repeats indicate satellite sequences. The Mg1 repetitive region and its flanking sequences exhibit significant homology to CvE, a member of the Pearl family of mobile elements found in the eastern oyster (Crassostrea virginica). Thus, the whole homologous region is designated MgE, the first putative transposable element characterized in M. galloprovincialis. The ApaI, Mg2, and Mg3 repeats are continuously arranged inside the introns of both the hsc70 and hsc71 genes. The presence of perfect inverted repeats flanking the ApaI-Mg2-Mg3 repetitive region, as well as a sequence analysis of the repeats, indicates a transposition-like insertion of this region. The genes of the HSP70 family are highly conserved, and the presence of repetitive DNA or of mobile elements inside their introns is reported here for the first time.
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Affiliation(s)
- Antonis Kourtidis
- Department of Genetics, Development, and Molecular Biology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki (AUTh), GR-54124, Thessaloniki, Greece.
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Petrović V, Plohl M. Sequence divergence and conservation in organizationally distinct subfamilies of Donax trunculus satellite DNA. Gene 2005; 362:37-43. [PMID: 16216450 DOI: 10.1016/j.gene.2005.06.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 06/03/2005] [Indexed: 10/25/2022]
Abstract
Characterization of a low-copy number DTF1 satellite DNA detected in the bivalve mollusk Donax trunculus revealed extensive grouping of monomer sequence variants into subfamilies identified by distinctive combinations of diagnostic nucleotides. It can be anticipated that a large number of subfamilies exists in the genome. In addition to the tandem organization of 169 bp long monomers, at least one subfamily was created through amplification of adjacent repeats in a higher order register. This complex satellite unit consists of two distinctive monomer variants that differ both in specific nucleotide changes and in a deleted segment partially substituted with a short unrelated sequence element. Most of the nucleotide substitutions differing between subfamilies are highly homogenized within a corresponding group of monomer variants, and intra-subfamily variability in general is low. Nucleotide diversity analysis of all sequenced variants of DTF1 satellite revealed the presence of two conserved segments, while the rest of the monomer sequence shows uniform and considerably higher level of variability. The persistence of conserved segments stands in contrast to the sequence and organizational divergence of monomer variant groups, and may indicate constraints in the evolution of DTF1 satellite repeats.
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Affiliation(s)
- Vlatka Petrović
- Ruder Bosković Institute, Department of Molecular Biology, Bijenicka 54, HR-10002, Zagreb, Croatia
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17
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Martínez-Lage A, Rodríguez-Fariña F, González-Tizón A, Méndez J. Origin and evolution of Mytilus mussel satellite DNAs. Genome 2005; 48:247-56. [PMID: 15838547 DOI: 10.1139/g04-115] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A phylogenetic reconstruction based on the amplification of 3 satellite DNAs (stDNAs) was carried out in 1 crustacean species and 15 bivalve species of the subclass Pteriomorphia (10, subfamily Mytilinae; 1, subfamily Litophaginae; 1, subfamily Modiolinae, all belonging to family Mytilidae; 1, family Arcidae; and 2, family Pectinidae). The sequences obtained showed motifs with high similarity to those of A and B boxes of tRNA promoter regions. Dot-blot hybridizations revealed that the 3 stDNAs are present mainly in high copy numbers for each species of the genus Mytilus, whereas for the other species they appear in low copy numbers. Maximum-parsimony trees evidenced a tendency to group Mytilus clones together, and species containing these sequences as a single copy were distributed among the different mytilids. Finally, the possible origin and evolution of these stDNAs is discussed.
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Affiliation(s)
- A Martínez-Lage
- Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidade da Coruña, Spain.
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Riginos C, Cunningham CW. INVITED REVIEW: Local adaptation and species segregation in two mussel (Mytilus edulis × Mytilus trossulus) hybrid zones. Mol Ecol 2004; 14:381-400. [PMID: 15660932 DOI: 10.1111/j.1365-294x.2004.02379.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Few marine hybrid zones have been studied extensively, the major exception being the hybrid zone between the mussels Mytilus edulis and Mytilus galloprovincialis in southwestern Europe. Here, we focus on two less studied hybrid zones that also involve Mytilus spp.; Mytilus edulis and Mytilus trossulus are sympatric and hybridize on both western and eastern coasts of the Atlantic Ocean. We review the dynamics of hybridization in these two hybrid zones and evaluate the role of local adaptation for maintaining species boundaries. In Scandinavia, hybridization and gene introgression is so extensive that no individuals with pure M. trossulus genotypes have been found. However, M. trossulus alleles are maintained at high frequencies in the extremely low salinity Baltic Sea for some allozyme genes. A synthesis of reciprocal transplantation experiments between different salinity regimes shows that unlinked Gpi and Pgm alleles change frequency following transplantation, such that post-transplantation allelic composition resembles native populations found in the same salinity. These experiments provide strong evidence for salinity adaptation at Gpi and Pgm (or genes linked to them). In the Canadian Maritimes, pure M. edulis and M. trossulus individuals are abundant, and limited data suggest that M. edulis predominates in low salinity and sheltered conditions, whereas M. trossulus are more abundant on the wave-exposed open coasts. We suggest that these conflicting patterns of species segregation are, in part, caused by local adaptation of Scandinavian M. trossulus to the extremely low salinity Baltic Sea environment.
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Affiliation(s)
- C Riginos
- Department of Biology, Box 90338, Duke University, Durham, NC 27708, USA
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López-Flores I, de la Herrán R, Garrido-Ramos MA, Boudry P, Ruiz-Rejón C, Ruiz-Rejón M. The molecular phylogeny of oysters based on a satellite DNA related to transposons. Gene 2004; 339:181-8. [PMID: 15363858 DOI: 10.1016/j.gene.2004.06.049] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 05/21/2004] [Accepted: 06/29/2004] [Indexed: 11/17/2022]
Abstract
We have analysed a centromeric satellite DNA family that is conserved in several commercial and non-commercial oyster species (Ostrea edulis, O. stentina, Crassostrea angulata, C. gigas, C. gasar, C. ariakensis, C. virginica and C. sikamea). This satellite DNA family is composed of AT-rich repeat sequences of 166+/-2 bp and presents a 9-bp motif similar to the mammalian CENP-B box. The homology of oyster HindIII satellite DNA with satellite DNAs from other bivalves and its relation to a part of a mobile element suggest the existence of an ancient transposable element as a generating unit of satellite DNA in bivalve molluscs. Taking advantage of its degree of conservation in oyster species, we have used this element as a taxonomic marker. This marker clearly supports a high degree of differentiation between O. edulis and O. stentina, and, conversely, upholds the contention that C. gigas and C. angulata are the same species. Finally, we have used HindIII satellite DNA as a phylogenetic marker between these species, revealing two clades, one formed by Asiatic species (C. angulata, C. gigas and C. ariakensis) and another by the European, American and African species (O. edulis, C. virginica and C. gasar, respectively).
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Affiliation(s)
- Inmaculada López-Flores
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
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