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Prunier J, Giguère I, Ryan N, Guy R, Soolanayakanahally R, Isabel N, MacKay J, Porth I. Gene copy number variations involved in balsam poplar (Populus balsamifera L.) adaptive variations. Mol Ecol 2018; 28:1476-1490. [PMID: 30270494 DOI: 10.1111/mec.14836] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/26/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022]
Abstract
Gene copy number variations (CNVs) involved in phenotypic variations have already been shown in plants, but genomewide testing of CNVs for adaptive variation was not doable until recent technological developments. Thus, reports of the genomic architecture of adaptation involving CNVs remain scarce to date. Here, we investigated F1 progenies of an intraprovenance cross (north-north cross, 58th parallel) and an interprovenances cross (north-south cross, 58th/49th parallels) for CNVs using comparative genomic hybridization on arrays of probes targeting gene sequences in balsam poplar (Populus balsamifera L.), a widespread North American forest tree. A total of 1,721 genes were found in varying copy numbers over the set of 19,823 tested genes. These gene CNVs presented an estimated average size of 8.3 kb and were distributed over poplar's 19 chromosomes including 22 hotspot regions. Gene CNVs number was higher for the interprovenance progeny in accordance with an expected higher genetic diversity related to the composite origin of this family. Regression analyses between gene CNVs and seven adaptive trait variations resulted in 23 significant links; among these adaptive gene CNVs, 30% were located in hotspots. One-to-five gene CNVs were found related to each of the measured adaptive traits and annotated for both biotic and abiotic stress responses. These annotations can be related to the occurrence of a higher pathogenic pressure in the southern parts of balsam poplar's distribution, and higher photosynthetic assimilation rates and water-use efficiency at high latitudes. Overall, our findings suggest that gene CNVs typically having higher mutation rates than SNPs may in fact represent efficient adaptive variations against fast-evolving pathogens.
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Affiliation(s)
- Julien Prunier
- Institute for System and Integrated Biology (IBIS), Université Laval, Québec, Québec, Canada.,Centre for Forest Research, Université Laval, Québec, Quebec, Canada
| | - Isabelle Giguère
- Institute for System and Integrated Biology (IBIS), Université Laval, Québec, Québec, Canada.,Centre for Forest Research, Université Laval, Québec, Quebec, Canada
| | - Natalie Ryan
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert Guy
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raju Soolanayakanahally
- Indian Head Research Farm, Agriculture and Agri-Food Canada, Indian Head, Saskatchewan, Canada
| | - Nathalie Isabel
- Laurentian Forest Centre, Canadian Forest Service, Natural Resources Canada, Québec, Quebec, Canada
| | - John MacKay
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Ilga Porth
- Institute for System and Integrated Biology (IBIS), Université Laval, Québec, Québec, Canada.,Centre for Forest Research, Université Laval, Québec, Quebec, Canada
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Lantieri F, Malacarne M, Gimelli S, Santamaria G, Coviello D, Ceccherini I. Custom Array Comparative Genomic Hybridization: the Importance of DNA Quality, an Expert Eye, and Variant Validation. Int J Mol Sci 2017; 18:E609. [PMID: 28287439 PMCID: PMC5372625 DOI: 10.3390/ijms18030609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/01/2017] [Accepted: 03/07/2017] [Indexed: 12/16/2022] Open
Abstract
The presence of false positive and false negative results in the Array Comparative Genomic Hybridization (aCGH) design is poorly addressed in literature reports. We took advantage of a custom aCGH recently carried out to analyze its design performance, the use of several Agilent aberrations detection algorithms, and the presence of false results. Our study provides a confirmation that the high density design does not generate more noise than standard designs and, might reach a good resolution. We noticed a not negligible presence of false negative and false positive results in the imbalances call performed by the Agilent software. The Aberration Detection Method 2 (ADM-2) algorithm with a threshold of 6 performed quite well, and the array design proved to be reliable, provided that some additional filters are applied, such as considering only intervals with average absolute log₂ratio above 0.3. We also propose an additional filter that takes into account the proportion of probes with log₂ratio exceeding suggestive values for gain or loss. In addition, the quality of samples was confirmed to be a crucial parameter. Finally, this work raises the importance of evaluating the samples profiles by eye and the necessity of validating the imbalances detected.
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Affiliation(s)
- Francesca Lantieri
- Dipartimento di Scienzedella Salute, Sezione di Biostatistica, Università degli Studi di Genova, Via Pastore 1, 16132 Genoa, Italy.
| | - Michela Malacarne
- Struttura Complessa Laboratorio Genetica Umana, E.O. Ospedali Galliera, Via Volta 6, 16128 Genoa, Italy.
| | - Stefania Gimelli
- Department of Medical Genetic and Laboratories, University Hospitals of Geneva, Bâtiment de Base 8C-3-840.3, 4 Rue Gabrielle-Perret-Gentil, 1211 Geneva 14, Switzerland.
| | - Giuseppe Santamaria
- UOC Genetica Medica, Istituto Giannina Gaslini, L. go G. Gaslini 5, 16148 Genoa, Italy.
| | - Domenico Coviello
- Struttura Complessa Laboratorio Genetica Umana, E.O. Ospedali Galliera, Via Volta 6, 16128 Genoa, Italy.
| | - Isabella Ceccherini
- UOC Genetica Medica, Istituto Giannina Gaslini, L. go G. Gaslini 5, 16148 Genoa, Italy.
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Panova M, Johansson T, Canbäck B, Bentzer J, Rosenblad MA, Johannesson K, Tunlid A, André C. Species and gene divergence in Littorina snails detected by array comparative genomic hybridization. BMC Genomics 2014; 15:687. [PMID: 25135785 PMCID: PMC4148934 DOI: 10.1186/1471-2164-15-687] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 08/11/2014] [Indexed: 12/11/2022] Open
Abstract
Background Array comparative genomic hybridization (aCGH) is commonly used to screen different types of genetic variation in humans and model species. Here, we performed aCGH using an oligonucleotide gene-expression array for a non-model species, the intertidal snail Littorina saxatilis. First, we tested what types of genetic variation can be detected by this method using direct re-sequencing and comparison to the Littorina genome draft. Secondly, we performed a genome-wide comparison of four closely related Littorina species: L. fabalis, L. compressa, L. arcana and L. saxatilis and of populations of L. saxatilis found in Spain, Britain and Sweden. Finally, we tested whether we could identify genetic variation underlying “Crab” and “Wave” ecotypes of L. saxatilis. Results We could reliably detect copy number variations, deletions and high sequence divergence (i.e. above 3%), but not single nucleotide polymorphisms. The overall hybridization pattern and number of significantly diverged genes were in close agreement with earlier phylogenetic reconstructions based on single genes. The trichotomy of L. arcana, L. compressa and L. saxatilis could not be resolved and we argue that these divergence events have occurred recently and very close in time. We found evidence for high levels of segmental duplication in the Littorina genome (10% of the transcripts represented on the array and up to 23% of the analyzed genomic fragments); duplicated genes and regions were mostly the same in all analyzed species. Finally, this method discriminated geographically distant populations of L. saxatilis, but we did not detect any significant genome divergence associated with ecotypes of L. saxatilis. Conclusions The present study provides new information on the sensitivity and the potential use of oligonucleotide arrays for genotyping of non-model organisms. Applying this method to Littorina species yields insights into genome evolution following the recent species radiation and supports earlier single-gene based phylogenies. Genetic differentiation of L. saxatilis ecotypes was not detected in this study, despite pronounced innate phenotypic differences. The reason may be that these differences are due to single-nucleotide polymorphisms. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-687) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marina Panova
- Department of Biological and Environmental Sciences - Tjärnö, Gothenburg University, Gothenburg, Sweden.
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Ogata T, Niihori T, Tanaka N, Kawai M, Nagashima T, Funayama R, Nakayama K, Nakashima S, Kato F, Fukami M, Aoki Y, Matsubara Y. TBX1 mutation identified by exome sequencing in a Japanese family with 22q11.2 deletion syndrome-like craniofacial features and hypocalcemia. PLoS One 2014; 9:e91598. [PMID: 24637876 PMCID: PMC3956758 DOI: 10.1371/journal.pone.0091598] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/12/2014] [Indexed: 11/18/2022] Open
Abstract
Background Although TBX1 mutations have been identified in patients with 22q11.2 deletion syndrome (22q11.2DS)-like phenotypes including characteristic craniofacial features, cardiovascular anomalies, hypoparathyroidism, and thymic hypoplasia, the frequency of TBX1 mutations remains rare in deletion-negative patients. Thus, it would be reasonable to perform a comprehensive genetic analysis in deletion-negative patients with 22q11.2DS-like phenotypes. Methodology/Principal Findings We studied three subjects with craniofacial features and hypocalcemia (group 1), two subjects with craniofacial features alone (group 2), and three subjects with normal phenotype within a single Japanese family. Fluorescence in situ hybridization analysis excluded chromosome 22q11.2 deletion, and genomewide array comparative genomic hybridization analysis revealed no copy number change specific to group 1 or groups 1+2. However, exome sequencing identified a heterozygous TBX1 frameshift mutation (c.1253delA, p.Y418fsX459) specific to groups 1+2, as well as six missense variants and two in-frame microdeletions specific to groups 1+2 and two missense variants specific to group 1. The TBX1 mutation resided at exon 9C and was predicted to produce a non-functional truncated protein missing the nuclear localization signal and most of the transactivation domain. Conclusions/Significance Clinical features in groups 1+2 are well explained by the TBX1 mutation, while the clinical effects of the remaining variants are largely unknown. Thus, the results exemplify the usefulness of exome sequencing in the identification of disease-causing mutations in familial disorders. Furthermore, the results, in conjunction with the previous data, imply that TBX1 isoform C is the biologically essential variant and that TBX1 mutations are associated with a wide phenotypic spectrum, including most of 22q11.2DS phenotypes.
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Affiliation(s)
- Tsutomu Ogata
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
- * E-mail:
| | - Tetsuya Niihori
- Department of Medical Genetics, Tohoku University School of Medicine, Sendai, Japan
| | - Noriko Tanaka
- Department of Pediatrics, Kurashiki Central Hospital, Kurashiki, Japan
| | - Masahiko Kawai
- Department of Pediatrics, Kyoto University School of Medicine, Kyoto, Japan
| | - Takeshi Nagashima
- Division of Cell Proliferation, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryo Funayama
- Division of Cell Proliferation, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Keiko Nakayama
- Division of Cell Proliferation, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shinichi Nakashima
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Fumiko Kato
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Maki Fukami
- National Research Institute for Child Health and Development, Tokyo, Japan
| | - Yoko Aoki
- Department of Medical Genetics, Tohoku University School of Medicine, Sendai, Japan
| | - Yoichi Matsubara
- Department of Medical Genetics, Tohoku University School of Medicine, Sendai, Japan
- National Research Institute for Child Health and Development, Tokyo, Japan
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Abstract
The field of cytogenetics has focused on studying the number, structure, function and origin of chromosomal abnormalities and the evolution of chromosomes. The development of fluorescent molecules that either directly or via an intermediate molecule bind to DNA has led to the development of fluorescent in situ hybridization (FISH), a technology linking cytogenetics to molecular genetics. This technique has a wide range of applications that increased the dimension of chromosome analysis. The field of cytogenetics is particularly important for medical diagnostics and research as well as for gene ordering and mapping. Furthermore, the increased application of molecular biology techniques, such as array-based technologies, has led to improved resolution, extending the recognized range of microdeletion/microduplication syndromes and genomic disorders. In adopting these newly expanded methods, cytogeneticists have used a range of technologies to study the association between visible chromosome rearrangements and defects at the single nucleotide level. Overall, molecular cytogenetic techniques offer a remarkable number of potential applications, ranging from physical mapping to clinical and evolutionary studies, making a powerful and informative complement to other molecular and genomic approaches. This manuscript does not present a detailed history of the development of molecular cytogenetics; however, references to historical reviews and experiments have been provided whenever possible. Herein, the basic principles of molecular cytogenetics, the technologies used to identify chromosomal rearrangements and copy number changes, and the applications for cytogenetics in biomedical diagnosis and research are presented and discussed.
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Affiliation(s)
- Mariluce Riegel
- Serviço de Genética Médica, Hospital de Clínicas, Porto Alegre, RS, Brazil . ; Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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