1
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Cavallini M, Lombardo G, Cantini C, Gerosa M, Binelli G. Genetic Insights into the Historical Attribution of Variety Names of Sweet Chestnut ( Castanea sativa Mill.) in Northern Italy. Genes (Basel) 2024; 15:866. [PMID: 39062645 PMCID: PMC11276188 DOI: 10.3390/genes15070866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 06/20/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
The sweet chestnut (Castanea sativa Mill.) is subject to the progressive disappearance of its traditional chestnut groves. In the northern part of Italy, where distribution of the sweet chestnut is fragmented, many local varieties continue to be identified mostly by oral tradition. We characterised by SSRs eleven historically recognised varieties of sweet chestnut in the area surrounding Lake Como, with the goal of giving a genetic basis to the traditional classification. We performed classical analysis about differentiation and used Bayesian approaches to detect population structure and to reconstruct demography. The results revealed that historical and genetic classifications are loosely linked when chestnut fruits are just "castagne", that is, normal fruits, but increasingly overlap where "marroni" (the most prized fruits) are concerned. Bayesian classification allowed us to identify a homogeneous gene cluster not recognised in the traditional assessment of the varieties and to reconstruct possible routes used for the propagation of sweet chestnut. We also reconstructed ancestral relationships between the different gene pools involved and dated ancestral lineages whose results fit with palynological data. We suggest that conservation strategies based on a genetic evaluation of the resource should also rely on traditional cultural heritage, which could reveal new sources of germplasm.
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Affiliation(s)
- Marta Cavallini
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, 21100 Varese, Italy; (M.C.); (G.L.)
| | - Gianluca Lombardo
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, 21100 Varese, Italy; (M.C.); (G.L.)
| | - Claudio Cantini
- Institute of Bioeconomy (IBE), Consiglio Nazionale Ricerche (CNR), 58022 Follonica, Italy;
| | - Mauro Gerosa
- Associazione Castanicoltori Lario Orientale, 23851 Sala al Barro, Italy;
| | - Giorgio Binelli
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, 21100 Varese, Italy; (M.C.); (G.L.)
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2
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Escudero M, Arroyo JM, Sánchez-Ramírez S, Jordano P. Founder events and subsequent genetic bottlenecks underlie karyotype evolution in the Ibero-North African endemic Carex helodes. ANNALS OF BOTANY 2024; 133:871-882. [PMID: 37400416 PMCID: PMC11082475 DOI: 10.1093/aob/mcad087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/29/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND AND AIMS Despite chromosomal evolution being one of the major drivers of diversification in plants, we do not yet have a clear view of how new chromosome rearrangements become fixed within populations, which is a crucial step forward for understanding chromosomal speciation. METHODS In this study, we test the role of genetic drift in the establishment of new chromosomal variants in the context of hybrid dysfunction models of chromosomal speciation. We genotyped 178 individuals from seven populations (plus 25 seeds from one population) across the geographical range of Carex helodes (Cyperaceae). We also characterized karyotype geographical patterns of the species across its distribution range. For one of the populations, we performed a detailed study of the fine-scale, local spatial distribution of its individuals and their genotypes and karyotypes. KEY RESULTS Synergistically, phylogeographical and karyotypic evidence revealed two main genetic groups: southwestern Iberian Peninsula vs. northwestern African populations; and within Europe our results suggest a west-to-east expansion with signals of genetic bottlenecks. Additionally, we inferred a pattern of descending dysploidy, plausibly as a result of a west-to-east process of post-glacial colonization in Europe. CONCLUSIONS Our results give experimental support to the role of geographical isolation, drift and inbreeding in the establishment of new karyotypes, which is key in the speciation models of hybrid dysfunction.
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Affiliation(s)
- Marcial Escudero
- Department of Plant Biology and Ecology, University of Seville, 41012 Seville, Spain
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
| | - Juan Miguel Arroyo
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
| | - Santiago Sánchez-Ramírez
- Department of Ecology and Evolutionary Biology, University of Toronto, M5S 3B2 Toronto, Ontario, Canada
| | - Pedro Jordano
- Department of Plant Biology and Ecology, University of Seville, 41012 Seville, Spain
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
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3
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van’t Hof AE, Whiteford S, Yung CJ, Yoshido A, Zrzavá M, de Jong MA, Tan KL, Zhu D, Monteiro A, Brakefield PM, Marec F, Saccheri IJ. Zygosity-based sex determination in a butterfly drives hypervariability of Masculinizer. SCIENCE ADVANCES 2024; 10:eadj6979. [PMID: 38701204 PMCID: PMC11067997 DOI: 10.1126/sciadv.adj6979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/03/2024] [Indexed: 05/05/2024]
Abstract
Nature has devised many ways of producing males and females. Here, we report on a previously undescribed mechanism for Lepidoptera that functions without a female-specific gene. The number of alleles or allele heterozygosity in a single Z-linked gene (BaMasc) is the primary sex-determining switch in Bicyclus anynana butterflies. Embryos carrying a single BaMasc allele develop into WZ (or Z0) females, those carrying two distinct alleles develop into ZZ males, while (ZZ) homozygotes initiate female development, have mismatched dosage compensation, and die as embryos. Consequently, selection against homozygotes has favored the evolution of spectacular allelic diversity: 205 different coding sequences of BaMasc were detected in a sample of 246 females. The structural similarity of a hypervariable region (HVR) in BaMasc to the HVR in Apis mellifera csd suggests molecular convergence between deeply diverged insect lineages. Our discovery of this primary switch highlights the fascinating diversity of sex-determining mechanisms and underlying evolutionary drivers.
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Affiliation(s)
- Arjen E. van’t Hof
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, 370 05 České Budějovice, Czech Republic
| | - Sam Whiteford
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
| | - Carl J. Yung
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
| | - Atsuo Yoshido
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, 370 05 České Budějovice, Czech Republic
| | - Magda Zrzavá
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, 370 05 České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
| | - Maaike A. de Jong
- Netherlands eScience Center, Science Park 402, 1098 XH Amsterdam, Netherlands
| | - Kian-Long Tan
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Dantong Zhu
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Antónia Monteiro
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | | | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, 370 05 České Budějovice, Czech Republic
| | - Ilik J. Saccheri
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
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4
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Dickson ZW, Golding GB. Evolution of Transcript Abundance is Influenced by Indels in Protein Low Complexity Regions. J Mol Evol 2024; 92:153-168. [PMID: 38485789 DOI: 10.1007/s00239-024-10158-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/24/2024] [Indexed: 04/02/2024]
Abstract
Protein Protein low complexity regions (LCRs) are compositionally biased amino acid sequences, many of which have significant evolutionary impacts on the proteins which contain them. They are mutationally unstable experiencing higher rates of indels and substitutions than higher complexity regions. LCRs also impact the expression of their proteins, likely through multiple effects along the path from gene transcription, through translation, and eventual protein degradation. It has been observed that proteins which contain LCRs are associated with elevated transcript abundance (TAb), despite having lower protein abundance. We have gathered and integrated human data to investigate the co-evolution of TAb and LCRs through ancestral reconstructions and model inference using an approximate Bayesian calculation based method. We observe that on short evolutionary timescales TAb evolution is significantly impacted by changes in LCR length, with insertions driving TAb down. But in contrast, the observed data is best explained by indel rates in LCRs which are unaffected by shifts in TAb. Our work demonstrates a coupling between LCR and TAb evolution, and the utility of incorporating multiple responses into evolutionary analyses.
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Affiliation(s)
| | - G Brian Golding
- Department of Biology, McMaster University, Hamilton, ON, Canada
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5
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Verbiest M, Maksimov M, Jin Y, Anisimova M, Gymrek M, Bilgin Sonay T. Mutation and selection processes regulating short tandem repeats give rise to genetic and phenotypic diversity across species. J Evol Biol 2023; 36:321-336. [PMID: 36289560 PMCID: PMC9990875 DOI: 10.1111/jeb.14106] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/29/2022] [Accepted: 08/01/2022] [Indexed: 02/03/2023]
Abstract
Short tandem repeats (STRs) are units of 1-6 bp that repeat in a tandem fashion in DNA. Along with single nucleotide polymorphisms and large structural variations, they are among the major genomic variants underlying genetic, and likely phenotypic, divergence. STRs experience mutation rates that are orders of magnitude higher than other well-studied genotypic variants. Frequent copy number changes result in a wide range of alleles, and provide unique opportunities for modulating complex phenotypes through variation in repeat length. While classical studies have identified key roles of individual STR loci, the advent of improved sequencing technology, high-quality genome assemblies for diverse species, and bioinformatics methods for genome-wide STR analysis now enable more systematic study of STR variation across wide evolutionary ranges. In this review, we explore mutation and selection processes that affect STR copy number evolution, and how these processes give rise to varying STR patterns both within and across species. Finally, we review recent examples of functional and adaptive changes linked to STRs.
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Affiliation(s)
- Max Verbiest
- Institute of Computational Life Sciences, School of Life Sciences and Facility ManagementZürich University of Applied SciencesWädenswilSwitzerland
- Department of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
| | - Mikhail Maksimov
- Department of Computer Science & EngineeringUniversity of California San DiegoLa JollaCaliforniaUSA
- Department of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Ye Jin
- Department of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
- Department of BioengineeringUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Maria Anisimova
- Institute of Computational Life Sciences, School of Life Sciences and Facility ManagementZürich University of Applied SciencesWädenswilSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
| | - Melissa Gymrek
- Department of Computer Science & EngineeringUniversity of California San DiegoLa JollaCaliforniaUSA
- Department of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Tugce Bilgin Sonay
- Institute of Ecology, Evolution and Environmental BiologyColumbia UniversityNew YorkNew YorkUSA
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6
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Song X, Yang T, Zhang X, Yuan Y, Yan X, Wei Y, Zhang J, Zhou C. Comparison of the Microsatellite Distribution Patterns in the Genomes of Euarchontoglires at the Taxonomic Level. Front Genet 2021; 12:622724. [PMID: 33719337 PMCID: PMC7953163 DOI: 10.3389/fgene.2021.622724] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/05/2021] [Indexed: 02/05/2023] Open
Abstract
Microsatellite or simple sequence repeat (SSR) instability within genes can induce genetic variation. The SSR signatures remain largely unknown in different clades within Euarchontoglires, one of the most successful mammalian radiations. Here, we conducted a genome-wide characterization of microsatellite distribution patterns at different taxonomic levels in 153 Euarchontoglires genomes. Our results showed that the abundance and density of the SSRs were significantly positively correlated with primate genome size, but no significant relationship with the genome size of rodents was found. Furthermore, a higher level of complexity for perfect SSR (P-SSR) attributes was observed in rodents than in primates. The most frequent type of P-SSR was the mononucleotide P-SSR in the genomes of primates, tree shrews, and colugos, while mononucleotide or dinucleotide motif types were dominant in the genomes of rodents and lagomorphs. Furthermore, (A)n was the most abundant motif in primate genomes, but (A)n, (AC)n, or (AG)n was the most abundant motif in rodent genomes which even varied within the same genus. The GC content and the repeat copy numbers of P-SSRs varied in different species when compared at different taxonomic levels, reflecting underlying differences in SSR mutation processes. Notably, the CDSs containing P-SSRs were categorized by functions and pathways using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes annotations, highlighting their roles in transcription regulation. Generally, this work will aid future studies of the functional roles of the taxonomic features of microsatellites during the evolution of mammals in Euarchontoglires.
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Affiliation(s)
- Xuhao Song
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Institute of Ecology, China West Normal University, Nanchong, China
| | - Tingbang Yang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Institute of Ecology, China West Normal University, Nanchong, China
| | - Xinyi Zhang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China
| | - Ying Yuan
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China
| | - Xianghui Yan
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China
| | - Yi Wei
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Institute of Ecology, China West Normal University, Nanchong, China
| | - Jun Zhang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Institute of Ecology, China West Normal University, Nanchong, China
| | - Caiquan Zhou
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China.,Institute of Ecology, China West Normal University, Nanchong, China
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7
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Guevara EK, Palo JU, Översti S, King JL, Seidel M, Stoljarova M, Wendt FR, Bus MM, Guengerich A, Church WB, Guillén S, Roewer L, Budowle B, Sajantila A. Genetic assessment reveals no population substructure and divergent regional and sex-specific histories in the Chachapoyas from northeast Peru. PLoS One 2020; 15:e0244497. [PMID: 33382772 PMCID: PMC7774974 DOI: 10.1371/journal.pone.0244497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 12/10/2020] [Indexed: 12/31/2022] Open
Abstract
Many native populations in South America have been severely impacted by two relatively recent historical events, the Inca and the Spanish conquest. However decisive these disruptive events may have been, the populations and their gene pools have been shaped markedly also by the history prior to the conquests. This study focuses mainly on the Chachapoya peoples that inhabit the montane forests on the eastern slopes of the northern Peruvian Andes, but also includes three distinct neighboring populations (the Jívaro, the Huancas and the Cajamarca). By assessing mitochondrial, Y-chromosomal and autosomal diversity in the region, we explore questions that have emerged from archaeological and historical studies of the regional culture (s). These studies have shown, among others, that Chachapoyas was a crossroads for Coast-Andes-Amazon interactions since very early times. In this study, we examine the following questions: 1) was there pre-Hispanic genetic population substructure in the Chachapoyas sample? 2) did the Spanish conquest cause a more severe population decline on Chachapoyan males than on females? 3) can we detect different patterns of European gene flow in the Chachapoyas region? and, 4) did the demographic history in the Chachapoyas resemble the one from the Andean area? Despite cultural differences within the Chachapoyas region as shown by archaeological and ethnohistorical research, genetic markers show no significant evidence for past or current population substructure, although an Amazonian gene flow dynamic in the northern part of this territory is suggested. The data also indicates a bottleneck c. 25 generations ago that was more severe among males than females, as well as divergent population histories for populations in the Andean and Amazonian regions. In line with previous studies, we observe high genetic diversity in the Chachapoyas, despite the documented dramatic population declines. The diverse topography and great biodiversity of the northeastern Peruvian montane forests are potential contributing agents in shaping and maintaining the high genetic diversity in the Chachapoyas region.
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Affiliation(s)
- Evelyn K. Guevara
- Department of Forensic Medicine, University of Helsinki, Helsinki, Finland
- * E-mail: (EKG); (AS)
| | - Jukka U. Palo
- Department of Forensic Medicine, University of Helsinki, Helsinki, Finland
- Forensic Genetics Unit, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Sanni Översti
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jonathan L. King
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Maria Seidel
- Department of Forensic Genetics, Institute of Legal Medicine and Forensic Sciences, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Monika Stoljarova
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Frank R. Wendt
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- Department of Psychiatry, Yale University School of Medicine and VA Connecticut Healthcare System, West Haven, Connecticut, United States of America
- Department of Microbiology, Immunology and Genetics, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Magdalena M. Bus
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- Department of Microbiology, Immunology and Genetics, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Anna Guengerich
- Eckerd College, Saint Petersburg, Florida, United States of America
| | - Warren B. Church
- Department of Earth and Space Sciences, Columbus State University, Columbus, Georgia, United States of America
| | | | - Lutz Roewer
- Department of Forensic Genetics, Institute of Legal Medicine and Forensic Sciences, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Bruce Budowle
- Center for Human Identification, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
- Department of Microbiology, Immunology and Genetics, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, United States of America
| | - Antti Sajantila
- Department of Forensic Medicine, University of Helsinki, Helsinki, Finland
- Forensic Medicine Unit, Finnish Institute for Health and Welfare, Helsinki, Finland
- * E-mail: (EKG); (AS)
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8
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Chung J, Maruvka YE, Sudhaman S, Kelly J, Haradhvala NJ, Bianchi V, Edwards M, Forster VJ, Nunes NM, Galati MA, Komosa M, Deshmukh S, Cabric V, Davidson S, Zatzman M, Light N, Hayes R, Brunga L, Anderson ND, Ho B, Hodel KP, Siddaway R, Morrissy AS, Bowers DC, Larouche V, Bronsema A, Osborn M, Cole KA, Opocher E, Mason G, Thomas GA, George B, Ziegler DS, Lindhorst S, Vanan M, Yalon-Oren M, Reddy AT, Massimino M, Tomboc P, Van Damme A, Lossos A, Durno C, Aronson M, Morgenstern DA, Bouffet E, Huang A, Taylor MD, Villani A, Malkin D, Hawkins CE, Pursell ZF, Shlien A, Kunkel TA, Getz G, Tabori U. DNA Polymerase and Mismatch Repair Exert Distinct Microsatellite Instability Signatures in Normal and Malignant Human Cells. Cancer Discov 2020; 11:1176-1191. [PMID: 33355208 DOI: 10.1158/2159-8290.cd-20-0790] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/23/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022]
Abstract
Although replication repair deficiency, either by mismatch repair deficiency (MMRD) and/or loss of DNA polymerase proofreading, can cause hypermutation in cancer, microsatellite instability (MSI) is considered a hallmark of MMRD alone. By genome-wide analysis of tumors with germline and somatic deficiencies in replication repair, we reveal a novel association between loss of polymerase proofreading and MSI, especially when both components are lost. Analysis of indels in microsatellites (MS-indels) identified five distinct signatures (MS-sigs). MMRD MS-sigs are dominated by multibase losses, whereas mutant-polymerase MS-sigs contain primarily single-base gains. MS deletions in MMRD tumors depend on the original size of the MS and converge to a preferred length, providing mechanistic insight. Finally, we demonstrate that MS-sigs can be a powerful clinical tool for managing individuals with germline MMRD and replication repair-deficient cancers, as they can detect the replication repair deficiency in normal cells and predict their response to immunotherapy. SIGNIFICANCE: Exome- and genome-wide MSI analysis reveals novel signatures that are uniquely attributed to mismatch repair and DNA polymerase. This provides new mechanistic insight into MS maintenance and can be applied clinically for diagnosis of replication repair deficiency and immunotherapy response prediction.This article is highlighted in the In This Issue feature, p. 995.
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Affiliation(s)
- Jiil Chung
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yosef E Maruvka
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts
| | - Sumedha Sudhaman
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jacalyn Kelly
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nicholas J Haradhvala
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts.,Harvard Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts
| | - Vanessa Bianchi
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa Edwards
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Victoria J Forster
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nuno M Nunes
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melissa A Galati
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Martin Komosa
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shriya Deshmukh
- Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,The Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Vanja Cabric
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Scott Davidson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Matthew Zatzman
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Nicholas Light
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Reid Hayes
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ledia Brunga
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nathaniel D Anderson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ben Ho
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University of Medicine, New Orleans, Louisiana
| | - Robert Siddaway
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - A Sorana Morrissy
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Charbonneau Cancer Institute and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Daniel C Bowers
- Department of Pediatrics and Harold C. Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center, Dallas, Texas.,Pauline Allen Gill Center for Cancer and Blood Disorders, Children's Health, Dallas, Texas
| | - Valérie Larouche
- Department of Pediatrics, Centre Mere-enfant Soleil du CHU de Quebec, CRCHU de Quebec, Universite Laval, Quebec City, Quebec, Canada
| | - Annika Bronsema
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Osborn
- Department of Haematology and Oncology, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Kristina A Cole
- Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Enrico Opocher
- Pediatric Oncology and Hematology, Azienda Ospedaliera-Universita' degli Studi di Padova, Padova, Italy
| | - Gary Mason
- Department of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania
| | - Gregory A Thomas
- Division of Pediatric Hematology-Oncology, Oregon Health and Science University, Portland, Oregon
| | - Ben George
- Division of Hematology and Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - David S Ziegler
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, New South Wales, Australia.,Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales, Australia
| | - Scott Lindhorst
- Neuro-Oncology, Department of Neurosurgery, and Department of Medicine, Division of Hematology/Medical Oncology, Medical University of South Carolina Charleston, South Carolina
| | - Magimairajan Vanan
- Department of Pediatric Hematology-Oncology, Cancer Care Manitoba; Research Institute in Oncology and Hematology (RIOH), University of Manitoba, Winnipeg, Manitoba, Canada
| | - Michal Yalon-Oren
- Pediatric Hemato-Oncology, Edmond and Lilly Safra Children's Hospital and Cancer Research Center, Sheba Medical Center, Tel Hashomer Affiliated to the Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Alyssa T Reddy
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Maura Massimino
- Pediatric Unit, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), Milano, Italy
| | - Patrick Tomboc
- Department of Pediatrics Section of Hematology-Oncology, WVU Medicine Children's, Morgantown, West Virginia
| | - An Van Damme
- Division of Hematology and Oncology, Department of Pediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Alexander Lossos
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Carol Durno
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada.,Division of Gastroenterology, Hepatology and Nutrition, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melyssa Aronson
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Daniel A Morgenstern
- Department of Paediatrics, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Eric Bouffet
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Annie Huang
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael D Taylor
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anita Villani
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - David Malkin
- Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cynthia E Hawkins
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Program in Cell Biology, The Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University of Medicine, New Orleans, Louisiana
| | - Adam Shlien
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Thomas A Kunkel
- Genome Integrity Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Durham, North Carolina
| | - Gad Getz
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts. .,Broad Institute of Harvard and MIT, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts
| | - Uri Tabori
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada. .,The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Hematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
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9
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Krajka A, Panasiuk I, Misiura A, Wójcik GM. On the mutation model used in the fingerprinting DNA. BIO-ALGORITHMS AND MED-SYSTEMS 2020. [DOI: 10.1515/bams-2020-0057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractObjectivesThe most common technique of determining biological paternity or another relationship among people are the investigations of DNA polymorphism called Fingerprinting DNA. The key concept of these investigations is the statistical analysis, which leads to obtain the likelihood ratio (LR), sometimes called the paternity index.MethodsAmong the different assumptions stated in these computations is a mutation model (this model is used for all the computations).Results and conclusionsAlthough its influence on LR is usually negligible, there are some situations (when the mother–child mutation arises) when it is crucial.
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Affiliation(s)
- Andrzej Krajka
- Chair of Intelligent Systems , Maria Curie-Sklodowska University , Lublin , Poland
| | - Ireneusz Panasiuk
- Chair of Neuroinformatics and Biomedical Engineering , Maria Curie-Sklodowska University , Lublin , Poland
| | - Adam Misiura
- Chair of Neuroinformatics and Biomedical Engineering , Maria Curie-Sklodowska University , Lublin , Poland
| | - Grzegorz M. Wójcik
- Chair of Neuroinformatics and Biomedical Engineering , Maria Curie-Sklodowska University , Lublin , Poland
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10
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Silver‐Gorges I, Koval J, Rodriguez‐Zarate CJ, Paladino FV, Jordan M. Large-scale connectivity, cryptic population structure, and relatedness in Eastern Pacific Olive ridley sea turtles ( Lepidochelys olivacea). Ecol Evol 2020; 10:8688-8704. [PMID: 32884651 PMCID: PMC7452818 DOI: 10.1002/ece3.6564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 06/04/2020] [Accepted: 06/15/2020] [Indexed: 12/29/2022] Open
Abstract
Endangered species are grouped into genetically discrete populations to direct conservation efforts. Mitochondrial control region (mtCR) haplotypes are used to elucidate deep divergences between populations, as compared to nuclear microsatellites that can detect recent structuring. When prior populations are unknown, it is useful to subject microsatellite data to clustering and/or ordination population inference. Olive ridley sea turtles (Lepidochelys olivacea) are the most abundant sea turtle, yet few studies have characterized olive ridley population structure. Recently, clustering results of olive ridleys in the Eastern Tropical Pacific Ocean suggested weak structuring (F ST = 0.02) between Mexico and Central America. We analyzed mtCR haplotypes, new microsatellite genotypes from Costa Rica, and preexisting microsatellite genotypes from olive ridleys across the Eastern Tropical Pacific, to further explore population structuring in this region. We subjected inferred populations to multiple analyses to explore the mechanisms behind their structuring. We found 10 mtCR haplotypes from 60 turtles nesting at three sites in Costa Rica, but did not detect divergence between Costa Rican sites, or between Central America and Mexico. In Costa Rica, clustering suggested one population with no structuring, but ordination suggested four cryptic clusters with moderate structuring (F ST = 0.08, p < .001). Across the Eastern Tropical Pacific, ordination suggested nine cryptic clusters with moderate structuring (F ST = 0.103, p < .001) that largely corresponded to Mexican and Central American populations. All ordination clusters displayed significant internal relatedness relative to global relatedness (p < .001) and contained numerous sibling pairs. This suggests that broadly dispersed family lineages have proliferated in Eastern Tropical Pacific olive ridleys and corroborates previous work showing basin-wide connectivity and shallow population structure in this region. The existence of broadly dispersed kin in Eastern Tropical Pacific olive ridleys has implications for management of olive ridleys in this region, and adds to our understanding of sea turtle ecology and life history, particularly in light of the natal-homing paradigm.
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Affiliation(s)
- Ian Silver‐Gorges
- Department of BiologyCenter for Marine Conservation and BiologyPurdue University‐Fort WayneFort WayneINUSA
| | - Julianne Koval
- Department of BiologyCenter for Marine Conservation and BiologyPurdue University‐Fort WayneFort WayneINUSA
| | - Clara J. Rodriguez‐Zarate
- Marine Turtle Conservation ProgrammeEmirates Nature in Association with World Wide Fund for Nature (WWF)DubaiUnited Arab Emirates
| | - Frank V. Paladino
- Department of BiologyCenter for Marine Conservation and BiologyPurdue University‐Fort WayneFort WayneINUSA
| | - Mark Jordan
- Department of BiologyCenter for Marine Conservation and BiologyPurdue University‐Fort WayneFort WayneINUSA
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11
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Andersen MM, Caliebe A, Kirkeby K, Knudsen M, Vihrs N, Curran JM. Estimation of Y haplotype frequencies with lower order dependencies. Forensic Sci Int Genet 2020; 46:102214. [DOI: 10.1016/j.fsigen.2019.102214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/05/2019] [Accepted: 11/29/2019] [Indexed: 12/01/2022]
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12
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Pelassa I, Cibelli M, Villeri V, Lilliu E, Vaglietti S, Olocco F, Ghirardi M, Montarolo PG, Corà D, Fiumara F. Compound Dynamics and Combinatorial Patterns of Amino Acid Repeats Encode a System of Evolutionary and Developmental Markers. Genome Biol Evol 2020; 11:3159-3178. [PMID: 31589292 PMCID: PMC6839033 DOI: 10.1093/gbe/evz216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2019] [Indexed: 01/05/2023] Open
Abstract
Homopolymeric amino acid repeats (AARs) like polyalanine (polyA) and polyglutamine (polyQ) in some developmental proteins (DPs) regulate certain aspects of organismal morphology and behavior, suggesting an evolutionary role for AARs as developmental "tuning knobs." It is still unclear, however, whether these are occasional protein-specific phenomena or hints at the existence of a whole AAR-based regulatory system in DPs. Using novel approaches to trace their functional and evolutionary history, we find quantitative evidence supporting a generalized, combinatorial role of AARs in developmental processes with evolutionary implications. We observe nonrandom AAR distributions and combinations in HOX and other DPs, as well as in their interactomes, defining elements of a proteome-wide combinatorial functional code whereby different AARs and their combinations appear preferentially in proteins involved in the development of specific organs/systems. Such functional associations can be either static or display detectable evolutionary dynamics. These findings suggest that progressive changes in AAR occurrence/combination, by altering embryonic development, may have contributed to taxonomic divergence, leaving detectable traces in the evolutionary history of proteomes. Consistent with this hypothesis, we find that the evolutionary trajectories of the 20 AARs in eukaryotic proteomes are highly interrelated and their individual or compound dynamics can sharply mark taxonomic boundaries, or display clock-like trends, carrying overall a strong phylogenetic signal. These findings provide quantitative evidence and an interpretive framework outlining a combinatorial system of AARs whose compound dynamics mark at the same time DP functions and evolutionary transitions.
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Affiliation(s)
- Ilaria Pelassa
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Marica Cibelli
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Veronica Villeri
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Elena Lilliu
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Serena Vaglietti
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Federica Olocco
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Mirella Ghirardi
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
| | - Pier Giorgio Montarolo
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
| | - Davide Corà
- Department of Translational Medicine, Piemonte Orientale University, Novara, Italy.,Center for Translational Research on Autoimmune and Allergic Disease (CAAD), Novara, Italy
| | - Ferdinando Fiumara
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
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13
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Sanín MJ, Zapata P, Pintaud JC, Galeano G, Bohórquez A, Tohme J, Hansen MM. Up and Down the Blind Alley: Population Divergence with Scant Gene Flow in an Endangered Tropical Lineage of Andean Palms (Ceroxylon quindiuense Clade: Ceroxyloideae). J Hered 2020; 108:288-298. [PMID: 28186241 DOI: 10.1093/jhered/esx006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/25/2017] [Indexed: 11/14/2022] Open
Abstract
Given the geographical complexity of the Andes, species distributions hold interesting information regarding the history of isolation and gene flow across geographic barriers and ecological gradients. Moreover, current threats to the region's enormous plant diversity pose an additional challenge to the understanding of these patterns. We explored the geographic structure of genetic diversity within the Ceroxylon quindiuense species complex (wax palms) at a regional scale, using a model-based approach to disentangle the historical mechanisms by which these species have dispersed over a range encompassing 17° of latitude in the tropical Andes. A total of 10 microsatellite loci were cross-amplified in 8 populations of the 3 species comprising the C. quindiuense complex. Analyses performed include estimates of molecular diversity and genetic structure, testing for genetic bottlenecks and an evaluation of the colonization scenario under approximate Bayesian computation. We showed that there was a geographical diversity gradient reflecting the orogenetic pattern of the northern Andes and its end at the cordilleras facing the Caribbean Sea. A general pattern of diversity suggests that the cordilleras of Colombia have served as historical recipients of gene flow occurring only scantly along the northern Andes. We provided evidence of important isolation between the largest populations of this complex, suggesting that both historical constraints to dispersal but also current anthropogenic effects might explain the high levels of population structuring. We provide a list of advisable measures for conservation stakeholders.
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Affiliation(s)
- María José Sanín
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Patricia Zapata
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Jean-Christophe Pintaud
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Gloria Galeano
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Adriana Bohórquez
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Joseph Tohme
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
| | - Michael Møller Hansen
- From the Universidad CES, Calle 10 A No. 22 - 04Medellín, Colombia (Sanín); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (Galeano); Agrobiodiversity Research Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia (Zapata, Bohórquez, and Tohme); Institut de Recherche pour le Développement IRD-CIRAD, TA A51/PS2, Montpellier cedex 5, France (Pintaud); and Department of Bioscience, Aarhus University, Aarhus, Denmark (Hansen)
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14
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Isolation and Molecular Typing of Leishmania infantum from Phlebotomus perfiliewi in a Re-Emerging Focus of Leishmaniasis, Northeastern Italy. Microorganisms 2019; 7:microorganisms7120644. [PMID: 31816970 PMCID: PMC6955719 DOI: 10.3390/microorganisms7120644] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/29/2019] [Accepted: 12/02/2019] [Indexed: 11/21/2022] Open
Abstract
Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies collected in a re-emerging focus of VL in the Bologna province. During the summer of 2016, 6114 sand flies were collected, identified, and tested for Leishmania detection. Of the identified sand flies, 96.5% were Phlebotomus (P.) perfiliewi and 3.5% were P. perniciosus. Detected parasites were characterized by biomolecular methods (multilocus microsatellite typing and characterization of repetitive region on chromosome 31), and quantified by real-time PCR. The prevalence of Leishmania infection in individually-tested P. perfiliewi sand flies varied from 6% to 10% with an increasing trend during the season. Promastigotes of L. infantum were isolated by dissection in one P. perfiliewi female; the isolated strain (Lein-pw) were closely related to Leishmania parasites from VL cases in northeastern Italy, but differed from strains isolated in dogs from the same area. Our findings strongly support the vector status of P. perfiliewi for human VL in the study area.
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15
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Estimates of mutation rates from incompatibilities are misleading - guidelines for publication and retrieval of mutation data urgently needed. FORENSIC SCIENCE INTERNATIONAL GENETICS SUPPLEMENT SERIES 2019. [DOI: 10.1016/j.fsigss.2019.10.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Gundlach S, Junge O, Wienbrandt L, Krawczak M, Caliebe A. Comparison of Markov Chain Monte Carlo Software for the Evolutionary Analysis of Y-Chromosomal Microsatellite Data. Comput Struct Biotechnol J 2019; 17:1082-1090. [PMID: 31452861 PMCID: PMC6700485 DOI: 10.1016/j.csbj.2019.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 06/17/2019] [Accepted: 07/25/2019] [Indexed: 11/28/2022] Open
Abstract
The evolutionary analysis of genetic data is an important subject of modern bioscience, with practical applications in diverse fields. Parameters of interest in this context include effective population sizes, mutation rates, population growth rates and the times to most recent common ancestors. Studying Y-chromosomal microsatellite data, in particular, has proven useful to unravel the recent patrilineal history of Homo sapiens populations. We compared the individual analysis options and technical details of four software tools that are widely used for this purpose, namely BATWING, BEAST, IMa2 and LAMARC, all of which use Bayesian coalescent-based Markov chain Monte Carlo (MCMC) methods for parameter estimation. More specifically, we simulated datasets for either eight or 20 hypothetical Y-chromosomal microsatellites, assuming a mutation rate of 0.0030 per generation and a constant or exponentially increasing population size, and used these data to evaluate the parameter estimation capacity of each tool. The datasets comprised between 100 and 1000 samples. In addition to runtime, the practical utility of the tools of interest can also be expected to depend critically upon the convergence behavior of the actual MCMC implementation. In fact, we found that runtime increased, and convergence rate decreased, with increasing sample size as expected. BATWING performed best with respect to runtime and convergence behavior, but only supports simple evolutionary models. As regards the spectrum of evolutionary models covered, and also in terms of cross-platform usability, BEAST provided the greatest flexibility. Finally, IMa2 and LAMARC turned out best to incorporate elaborate migration models in the analysis process.
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Affiliation(s)
- Sven Gundlach
- Institute of Medical Informatics and Statistics, Kiel University, University Hospital Schleswig-Holstein, Brunswiker Strasse 10, 24105 Kiel, Germany
| | - Olaf Junge
- Institute of Medical Informatics and Statistics, Kiel University, University Hospital Schleswig-Holstein, Brunswiker Strasse 10, 24105 Kiel, Germany
| | - Lars Wienbrandt
- Institute of Clinical Molecular Biology, Kiel University, University Hospital Schleswig-Holstein, Rosalind-Franklin-Strasse 12, 24105 Kiel, Germany
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Kiel University, University Hospital Schleswig-Holstein, Brunswiker Strasse 10, 24105 Kiel, Germany
| | - Amke Caliebe
- Institute of Medical Informatics and Statistics, Kiel University, University Hospital Schleswig-Holstein, Brunswiker Strasse 10, 24105 Kiel, Germany
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17
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Biogeographical origin and timing of the founder ichthyosis TGM1 c.1187G > A mutation in an isolated Ecuadorian population. Sci Rep 2019; 9:7175. [PMID: 31073126 PMCID: PMC6509209 DOI: 10.1038/s41598-019-43133-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 04/11/2019] [Indexed: 11/22/2022] Open
Abstract
An unusually high frequency of the lamellar ichthyosis TGM1 mutation, c.1187G > A, has been observed in the Ecuadorian province of Manabí. Recently, the same mutation has been detected in a Galician patient (Northwest of Spain). By analyzing patterns of genetic variation around this mutation in Ecuadorian patients and population matched controls, we were able to estimate the age of c.1187G > A and the time to their most recent common ancestor (TMRCA) of c.1187G > A Ecuadorian carriers. While the estimated mutation age is 41 generations ago (~1,025 years ago [ya]), the TMRCA of Ecuadorian c.1187G > A carrier haplotypes dates to just 17 generations (~425 ya). Probabilistic-based inferences of local ancestry allowed us to infer a most likely European origin of a few (16% to 30%) Ecuadorian haplotypes carrying this mutation. In addition, inferences on demographic historical changes based on c.1187G > A Ecuadorian carrier haplotypes estimated an exponential population growth starting ~20 generations, compatible with a recent founder effect occurring in Manabí. Two main hypotheses can be considered for the origin of c.1187G > A: (i) the mutation could have arisen in Spain >1,000 ya (being Galicia the possible homeland) and then carried to Ecuador by Spaniards in colonial times ~400 ya, and (ii) two independent mutational events originated this mutation in Ecuador and Galicia. The geographic and cultural characteristics of Manabí could have favored a founder effect that explains the high prevalence of TGM1 c.1187G > A in this region.
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18
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Bouckaert R, Vaughan TG, Barido-Sottani J, Duchêne S, Fourment M, Gavryushkina A, Heled J, Jones G, Kühnert D, De Maio N, Matschiner M, Mendes FK, Müller NF, Ogilvie HA, du Plessis L, Popinga A, Rambaut A, Rasmussen D, Siveroni I, Suchard MA, Wu CH, Xie D, Zhang C, Stadler T, Drummond AJ. BEAST 2.5: An advanced software platform for Bayesian evolutionary analysis. PLoS Comput Biol 2019; 15:e1006650. [PMID: 30958812 PMCID: PMC6472827 DOI: 10.1371/journal.pcbi.1006650] [Citation(s) in RCA: 1610] [Impact Index Per Article: 322.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/18/2019] [Accepted: 02/04/2019] [Indexed: 11/18/2022] Open
Abstract
Elaboration of Bayesian phylogenetic inference methods has continued at pace in recent years with major new advances in nearly all aspects of the joint modelling of evolutionary data. It is increasingly appreciated that some evolutionary questions can only be adequately answered by combining evidence from multiple independent sources of data, including genome sequences, sampling dates, phenotypic data, radiocarbon dates, fossil occurrences, and biogeographic range information among others. Including all relevant data into a single joint model is very challenging both conceptually and computationally. Advanced computational software packages that allow robust development of compatible (sub-)models which can be composed into a full model hierarchy have played a key role in these developments. Developing such software frameworks is increasingly a major scientific activity in its own right, and comes with specific challenges, from practical software design, development and engineering challenges to statistical and conceptual modelling challenges. BEAST 2 is one such computational software platform, and was first announced over 4 years ago. Here we describe a series of major new developments in the BEAST 2 core platform and model hierarchy that have occurred since the first release of the software, culminating in the recent 2.5 release.
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Affiliation(s)
- Remco Bouckaert
- Centre of Computational Evolution, University of Auckland, Auckland, New Zealand
- Max Planck Institute for the Science of Human History, Jena, Germany
| | - Timothy G. Vaughan
- ETH Zürich, Department of Biosystems Science and Engineering, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Joëlle Barido-Sottani
- ETH Zürich, Department of Biosystems Science and Engineering, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Sebastián Duchêne
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Mathieu Fourment
- ithree institute, University of Technology Sydney, Sydney, Australia
| | | | | | - Graham Jones
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE 405 30 Göteborg, Sweden
| | - Denise Kühnert
- Max Planck Institute for the Science of Human History, Jena, Germany
| | - Nicola De Maio
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridgeshire, UK
| | - Michael Matschiner
- Department of Environmental Sciences, University of Basel, 4051 Basel, Switzerland
| | - Fábio K. Mendes
- Centre of Computational Evolution, University of Auckland, Auckland, New Zealand
| | - Nicola F. Müller
- ETH Zürich, Department of Biosystems Science and Engineering, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Huw A. Ogilvie
- Department of Computer Science, Rice University, Houston, TX 77005-1892, USA
| | - Louis du Plessis
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Alex Popinga
- Centre of Computational Evolution, University of Auckland, Auckland, New Zealand
| | - Andrew Rambaut
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, EH9 3FL UK
| | - David Rasmussen
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA
| | - Igor Siveroni
- Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, W2 1PG, UK
| | - Marc A. Suchard
- Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Chieh-Hsi Wu
- Department of Statistics, University of Oxford, OX1 3LB, UK
| | - Dong Xie
- Centre of Computational Evolution, University of Auckland, Auckland, New Zealand
| | - Chi Zhang
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Tanja Stadler
- ETH Zürich, Department of Biosystems Science and Engineering, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Alexei J. Drummond
- Centre of Computational Evolution, University of Auckland, Auckland, New Zealand
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19
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Rugna G, Carra E, Bergamini F, Calzolari M, Salvatore D, Corpus F, Gennari W, Baldelli R, Fabbi M, Natalini S, Vitale F, Varani S, Merialdi G. Multilocus microsatellite typing (MLMT) reveals host-related population structure in Leishmania infantum from northeastern Italy. PLoS Negl Trop Dis 2018; 12:e0006595. [PMID: 29975697 PMCID: PMC6057669 DOI: 10.1371/journal.pntd.0006595] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 07/24/2018] [Accepted: 06/08/2018] [Indexed: 11/28/2022] Open
Abstract
Background Visceral leishmaniasis (VL) caused by Leishmania infantum is an ongoing health problem in southern Europe, where dogs are considered the main reservoirs of the disease. Current data point to a northward spread of VL and canine leishmaniasis (CanL) in Italy, with new foci in northern regions previously regarded as non-endemic. Methodology/Principal findings Multilocus microsatellite typing (MLMT) was performed to investigate genetic diversity and population structure of L. infantum on 55 samples from infected humans, dogs and sand flies of the E-R region between 2013 and 2017. E-R samples were compared with 10 L. infantum samples from VL cases in other Italian regions (extra E-R) and with 52 strains within the L. donovani complex. Data displayed significant microsatellite polymorphisms with low allelic heterozygosity. Forty-one unique and eight repeated MLMT profiles were recognized among the L. infantum samples from E-R, and ten unique MLMT profiles were assigned to the extra E-R samples. Bayesian analysis assigned E-R samples to two distinct populations, with further sub-structuring within each of them; all CanL samples belonged to one population, genetically related to Mediterranean MON-1 strains, while all but one VL cases as well as the isolate from the sand fly Phlebotomus perfiliewi fell under the second population. Conversely, VL samples from other Italian regions proved to be genetically similar to strains circulating in dogs. Conclusions/Significance A peculiar epidemiological situation was observed in northeastern Italy, with the co-circulation of two distinct populations of L. infantum; one population mainly detected in dogs and the other population detected in humans and in a sand fly. While the classical cycle of CanL in Italy fits well into the data obtained for the first population, the population found in infected humans exhibits a different cycle, probably not involving a canine reservoir. This study can contribute to a better understanding of the population structure of L. infantum circulating in northeastern Italy, thus providing useful epidemiologic information for public health authorities. Visceral leishmaniasis is a sand fly-borne disease caused by protozoan parasites of the genus Leishmania. Leishmania infantum is the only parasitic species circulating in Italy and dogs are considered the main reservoirs of the disease. In this study, 55 L. infantum strains obtained from humans, dogs and sand flies from the Emiliana-Romagna (E-R) region, northeastern Italy, were assessed using multilocus microsatellite typing, a tool applied for population genetic studies. Results were compared with those obtained from 10 samples of visceral leishmaniasis cases occurring in other Italian regions and with 52 strains of the L. donovani complex from other foci of leishmaniasis. Our genetic analysis revealed that canine and human L. infantum strains from the E-R region were separated in two distinct populations; all samples obtained from dogs belonged to one population, while all but one human samples as well as a sand fly sample fell under another population. Samples from patients with visceral leishmaniasis from other Italian regions proved to be genetically similar to strains circulating in dogs. Our findings raise questions on the role of dogs as main reservoirs for human visceral leishmaniasis in the investigated area of northeastern Italy.
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Affiliation(s)
- Gianluca Rugna
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
- * E-mail:
| | - Elena Carra
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
| | - Federica Bergamini
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
| | - Mattia Calzolari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
| | - Daniela Salvatore
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Italy
| | - Francesco Corpus
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
| | - William Gennari
- Dipartimento Integrati Interaziendali Medicina di Laboratorio e Anatomia Patologica, Azienda Ospedaliero-Universitaria, Policlinico di Modena, Italy
| | - Raffaella Baldelli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Italy
| | - Massimo Fabbi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
| | - Silvano Natalini
- Department of Animal Health, Azienda Unità Sanitaria Locale, Bologna, Italy
| | - Fabrizio Vitale
- National Reference Center for Leishmaniasis (C.Re.Na.L.), Istituto Zooprofilattico Sperimentale della Sicilia, Palermo, Italy
| | - Stefania Varani
- Unit of Clinical Microbiology, Regional Reference Centre for Microbiological Emergencies (CRREM), St. Orsola-Malpighi University Hospital, Bologna, Italy
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Italy
| | - Giuseppe Merialdi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, Brescia, Italy
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Fungtammasan A, Tomaszkiewicz M, Campos-Sánchez R, Eckert KA, DeGiorgio M, Makova KD. Reverse Transcription Errors and RNA-DNA Differences at Short Tandem Repeats. Mol Biol Evol 2016; 33:2744-58. [PMID: 27413049 PMCID: PMC5026258 DOI: 10.1093/molbev/msw139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Transcript variation has important implications for organismal function in health and disease. Most transcriptome studies focus on assessing variation in gene expression levels and isoform representation. Variation at the level of transcript sequence is caused by RNA editing and transcription errors, and leads to nongenetically encoded transcript variants, or RNA–DNA differences (RDDs). Such variation has been understudied, in part because its detection is obscured by reverse transcription (RT) and sequencing errors. It has only been evaluated for intertranscript base substitution differences. Here, we investigated transcript sequence variation for short tandem repeats (STRs). We developed the first maximum-likelihood estimator (MLE) to infer RT error and RDD rates, taking next generation sequencing error rates into account. Using the MLE, we empirically evaluated RT error and RDD rates for STRs in a large-scale DNA and RNA replicated sequencing experiment conducted in a primate species. The RT error rates increased exponentially with STR length and were biased toward expansions. The RDD rates were approximately 1 order of magnitude lower than the RT error rates. The RT error rates estimated with the MLE from a primate data set were concordant with those estimated with an independent method, barcoded RNA sequencing, from a Caenorhabditis elegans data set. Our results have important implications for medical genomics, as STR allelic variation is associated with >40 diseases. STR nonallelic transcript variation can also contribute to disease phenotype. The MLE and empirical rates presented here can be used to evaluate the probability of disease-associated transcripts arising due to RDD.
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Affiliation(s)
- Arkarachai Fungtammasan
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Huck Institute of Genome Sciences, Pennsylvania State University
| | - Marta Tomaszkiewicz
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University
| | - Rebeca Campos-Sánchez
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University
| | - Kristin A Eckert
- Center for Medical Genomics, Pennsylvania State University Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, The Pennsylvania State University College of Medicine
| | - Michael DeGiorgio
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Institute for CyberScience, Pennsylvania State University
| | - Kateryna D Makova
- Department of Biology, Pennsylvania State University Center for Medical Genomics, Pennsylvania State University Huck Institute of Genome Sciences, Pennsylvania State University
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Willems T, Gymrek M, Poznik G, Tyler-Smith C, Erlich Y, Erlich Y. Population-Scale Sequencing Data Enable Precise Estimates of Y-STR Mutation Rates. Am J Hum Genet 2016; 98:919-933. [PMID: 27126583 DOI: 10.1016/j.ajhg.2016.04.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 04/01/2016] [Indexed: 01/23/2023] Open
Abstract
Short tandem repeats (STRs) are mutation-prone loci that span nearly 1% of the human genome. Previous studies have estimated the mutation rates of highly polymorphic STRs by using capillary electrophoresis and pedigree-based designs. Although this work has provided insights into the mutational dynamics of highly mutable STRs, the mutation rates of most others remain unknown. Here, we harnessed whole-genome sequencing data to estimate the mutation rates of Y chromosome STRs (Y-STRs) with 2-6 bp repeat units that are accessible to Illumina sequencing. We genotyped 4,500 Y-STRs by using data from the 1000 Genomes Project and the Simons Genome Diversity Project. Next, we developed MUTEA, an algorithm that infers STR mutation rates from population-scale data by using a high-resolution SNP-based phylogeny. After extensive intrinsic and extrinsic validations, we harnessed MUTEA to derive mutation-rate estimates for 702 polymorphic STRs by tracing each locus over 222,000 meioses, resulting in the largest collection of Y-STR mutation rates to date. Using our estimates, we identified determinants of STR mutation rates and built a model to predict rates for STRs across the genome. These predictions indicate that the load of de novo STR mutations is at least 75 mutations per generation, rivaling the load of all other known variant types. Finally, we identified Y-STRs with potential applications in forensics and genetic genealogy, assessed the ability to differentiate between the Y chromosomes of father-son pairs, and imputed Y-STR genotypes.
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Affiliation(s)
| | | | | | | | | | - Yaniv Erlich
- New York Genome Center, New York, NY 10013, USA; Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02139, USA; Department of Computer Science, Fu Foundation School of Engineering, Columbia University, New York, NY 10027, USA; Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA.
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Kitavi M, Downing T, Lorenzen J, Karamura D, Onyango M, Nyine M, Ferguson M, Spillane C. The triploid East African Highland Banana (EAHB) genepool is genetically uniform arising from a single ancestral clone that underwent population expansion by vegetative propagation. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2016; 129:547-61. [PMID: 26743524 DOI: 10.1007/s00122-015-2647-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/30/2015] [Indexed: 05/04/2023]
Abstract
All East African Highland Banana varieties are genetically uniform having arisen from a single clone introduced to Africa. East African Highland bananas (EAHBs) are a subgroup of triploid (AAA genome) bananas of importance to food security in the Great Lakes region of Africa. Little is known about their genetic variation, population structure and evolutionary history. Ninety phenotypically diverse EAHB cultivars were genotyped at 100 SSR microsatellite markers to investigate population genetic diversity, the correlation of genetic variability with morphological classes, and evolutionary origins since introduction to Africa. Population-level statistics were compared to those for plantain (AAB) and dessert (AAA) cultivars representing other M. acuminata subgroups. EAHBs displayed minimal genetic variation and are largely genetically uniform, irrespective of whether they were derived from the distinct Ugandan or Kenyan germplasm collections. No association was observed between EAHB genetic diversity and currently employed morphological taxonomic systems for EAHB germplasm. Population size dynamics indicated that triploid EAHBs arose as a single hybridization event, which generated a genetic bottleneck during foundation of the EAHB genepool. As EAHB triploids are sterile, subsequent asexual vegetative propagation of EAHBs allowed a recent rapid expansion in population size. This provided a basis for emergence of genetically near-isogenic somatic mutants selected across farmers and environments in East Africa over the past 2000 years since EAHBs were first introduced to the African continent.
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Affiliation(s)
- Mercy Kitavi
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), School of Natural Sciences, C306 Aras de Brun, National University of Ireland Galway, University Road, Galway, Ireland
- International Institute for Tropical Agriculture (IITA), Biosciences Eastern and Central Africa (BecA-ILRI), P.O. Box 30709-00100, Nairobi, Kenya
| | - Tim Downing
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, University Road, Galway, Ireland
| | - Jim Lorenzen
- International Institute for Tropical Agriculture (IITA), Biosciences Eastern and Central Africa (BecA-ILRI), P.O. Box 30709-00100, Nairobi, Kenya
- Bill and Melinda Gates Foundation, 500 5th Ave N, Seattle, WA, 98102, USA
| | - Deborah Karamura
- Bioversity International, PLOT 106, Katalima Road, P.O. Box 24384, Kampala, Uganda
| | - Margaret Onyango
- Kenya Agricultural Research Institute (KARI), KARI, Kisii Centre, P.O. Box 523-40200, Kisii, Kenya
| | - Moses Nyine
- International Institute for Tropical Agriculture (IITA), Biosciences Eastern and Central Africa (BecA-ILRI), P.O. Box 30709-00100, Nairobi, Kenya
| | - Morag Ferguson
- International Institute for Tropical Agriculture (IITA), Biosciences Eastern and Central Africa (BecA-ILRI), P.O. Box 30709-00100, Nairobi, Kenya
| | - Charles Spillane
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), School of Natural Sciences, C306 Aras de Brun, National University of Ireland Galway, University Road, Galway, Ireland.
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23
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Chenet SM, Taylor JE, Blair S, Zuluaga L, Escalante AA. Longitudinal analysis of Plasmodium falciparum genetic variation in Turbo, Colombia: implications for malaria control and elimination. Malar J 2015; 14:363. [PMID: 26395166 PMCID: PMC4578328 DOI: 10.1186/s12936-015-0887-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/02/2015] [Indexed: 11/15/2022] Open
Abstract
Background Malaria programmes estimate changes in prevalence to evaluate their efficacy. In this study, parasite genetic data was used to explore how the demography of the parasite population can inform about the processes driving variation in prevalence. In particular, how changes in treatment and population movement have affected malaria prevalence in an area with seasonal malaria. Methods Samples of Plasmodium falciparum collected over 8 years from a population in Turbo, Colombia were genotyped at nine microsatellite loci and three drug-resistance loci. These data were analysed using several population genetic methods to detect changes in parasite genetic diversity and population structure. In addition, a coalescent-based method was used to estimate substitution rates at the microsatellite loci. Results The estimated mean microsatellite substitution rates varied between 5.35 × 10−3 and 3.77 × 10−2 substitutions/locus/month. Cluster analysis identified six distinct parasite clusters, five of which persisted for the full duration of the study. However, the frequencies of the clusters varied significantly between years, consistent with a small effective population size. Conclusions Malaria control programmes can detect re-introductions and changes in transmission using rapidly evolving microsatellite loci. In this population, the steadily decreasing diversity and the relatively constant effective population size suggest that an increase in malaria prevalence from 2004 to 2007 was primarily driven by local rather than imported cases. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0887-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stella M Chenet
- School of Life Sciences, Arizona State University, Tempe, AZ, USA.
| | - Jesse E Taylor
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, USA.
| | - Silvia Blair
- Malaria Group, Universidad de Antioquia, Medellín, Colombia.
| | - Lina Zuluaga
- Malaria Group, Universidad de Antioquia, Medellín, Colombia.
| | - Ananias A Escalante
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, USA.
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24
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Furman BLS, Scheffers BR, Taylor M, Davis C, Paszkowski CA. Limited genetic structure in a wood frog (Lithobates sylvaticus) population in an urban landscape inhabiting natural and constructed wetlands. CONSERV GENET 2015. [DOI: 10.1007/s10592-015-0757-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Kwong M, Pemberton TJ. Sequence differences at orthologous microsatellites inflate estimates of human-chimpanzee differentiation. BMC Genomics 2014; 15:990. [PMID: 25407736 PMCID: PMC4253012 DOI: 10.1186/1471-2164-15-990] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 10/30/2014] [Indexed: 02/06/2023] Open
Abstract
Background Microsatellites---contiguous arrays of 2–6 base-pair motifs---have formed the cornerstone of population-genetic studies for over two decades. Their genotype data typically takes the form of PCR fragment lengths obtained using locus-specific primer pairs to amplify the genomic region encompassing the microsatellite. Recently, we reported a dataset of 5,795 human and 84 chimpanzee individuals with genotypes at 246 human-derived autosomal microsatellites as a resource to facilitate interspecies comparisons. A major assumption underlying this dataset is that PCR amplicons at orthologous microsatellites are commensurable between species. Results We find this assumption to be frequently incorrect owing to discordance in microsatellite organization and variability, as well as nontrivial length imbalances caused by small species-specific indels in microsatellite flanking sequences. Converting PCR fragment lengths into the repeat numbers they represent at 138 microsatellites whose organization and variability was found to be highly similar in both species, we show that interspecies incommensurability among PCR amplicons can inflate FST and DPS estimates by up to 10.6%. Separate investigations of determinants of microsatellite variability in humans and chimpanzees uncover similar patterns with mean and maximum numbers of repeats, as well as numbers and ranges of distinct alleles, all important factors in predicting heterozygosity. In contrast, across microsatellites, numbers of repeats were significantly smaller in chimpanzees than in humans, while numbers and ranges of distinct alleles were instead larger. Conclusions Our findings have fundamental implications for interspecies comparisons using microsatellites and offer new opportunities for more accurate comparisons of patterns of human and chimpanzee genetic variation in numerous areas of application. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-990) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Trevor J Pemberton
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
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26
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Abstract
Birth-death processes (BDPs) are continuous-time Markov chains that track the number of "particles" in a system over time. While widely used in population biology, genetics and ecology, statistical inference of the instantaneous particle birth and death rates remains largely limited to restrictive linear BDPs in which per-particle birth and death rates are constant. Researchers often observe the number of particles at discrete times, necessitating data augmentation procedures such as expectation-maximization (EM) to find maximum likelihood estimates. For BDPs on finite state-spaces, there are powerful matrix methods for computing the conditional expectations needed for the E-step of the EM algorithm. For BDPs on infinite state-spaces, closed-form solutions for the E-step are available for some linear models, but most previous work has resorted to time-consuming simulation. Remarkably, we show that the E-step conditional expectations can be expressed as convolutions of computable transition probabilities for any general BDP with arbitrary rates. This important observation, along with a convenient continued fraction representation of the Laplace transforms of the transition probabilities, allows for novel and efficient computation of the conditional expectations for all BDPs, eliminating the need for truncation of the state-space or costly simulation. We use this insight to derive EM algorithms that yield maximum likelihood estimation for general BDPs characterized by various rate models, including generalized linear models. We show that our Laplace convolution technique outperforms competing methods when they are available and demonstrate a technique to accelerate EM algorithm convergence. We validate our approach using synthetic data and then apply our methods to cancer cell growth and estimation of mutation parameters in microsatellite evolution.
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Affiliation(s)
- Forrest W Crawford
- Department of Biostatistics, Yale University, 60 College Street, Box 208034, New Haven, CT 06510 USA
| | - Vladimir N Minin
- Department of Statistics, University of Washington, Padelford Hall C-315, Box 354322, Seattle, WA 98195-4322 USA
| | - Marc A Suchard
- Department of Biomathematics, University of California Los Angeles, 6558 Gonda Building, Los Angeles, CA 90095-1766 USA ; Department of Biostatistics, University of California Los Angeles, 6558 Gonda Building, Los Angeles, CA 90095-1766 USA ; Department of Human Genetics, University of California Los Angeles, 6558 Gonda Building, Los Angeles, CA 90095-1766 USA
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27
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Genome-wide scan for analysis of simple and imperfect microsatellites in diverse carlaviruses. INFECTION GENETICS AND EVOLUTION 2014; 21:287-94. [DOI: 10.1016/j.meegid.2013.11.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/15/2013] [Accepted: 11/21/2013] [Indexed: 01/08/2023]
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28
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Donnelly RK, Harper GL, Morgan AJ, Orozco-Terwengel P, Pinto-Juma GA, Bruford MW. Nuclear DNA recapitulates the cryptic mitochondrial lineages ofLumbricus rubellusand suggests the existence of cryptic species in an ecotoxological soil sentinel. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12171] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert K. Donnelly
- Faculty of Health, Sport and Science; University of Glamorgan; Llantwit Road Trefforest Mid Glamorgan CF37 1DL UK
- Cardiff School of Biosciences; Cardiff University; PO Box 915 Cardiff CF10 3TL UK
| | - Georgina L. Harper
- Faculty of Health, Sport and Science; University of Glamorgan; Llantwit Road Trefforest Mid Glamorgan CF37 1DL UK
| | - A. John Morgan
- Cardiff School of Biosciences; Cardiff University; PO Box 915 Cardiff CF10 3TL UK
| | | | | | - Michael W. Bruford
- Cardiff School of Biosciences; Cardiff University; PO Box 915 Cardiff CF10 3TL UK
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Loire E, Higuet D, Netter P, Achaz G. Evolution of coding microsatellites in primate genomes. Genome Biol Evol 2013; 5:283-95. [PMID: 23315383 PMCID: PMC3590770 DOI: 10.1093/gbe/evt003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Microsatellites (SSRs) are highly susceptible to expansions and contractions. When located in a coding sequence, the insertion or the deletion of a single unit for a mono-, di-, tetra-, or penta(nucleotide)-SSR creates a frameshift. As a consequence, one would expect to find only very few of these SSRs in coding sequences because of their strong deleterious potential. Unexpectedly, genomes contain many coding SSRs of all types. Here, we report on a study of their evolution in a phylogenetic context using the genomes of four primates: human, chimpanzee, orangutan, and macaque. In a set of 5,015 orthologous genes unambiguously aligned among the four species, we show that, except for tri- and hexa-SSRs, for which insertions and deletions are frequently observed, SSRs in coding regions evolve mainly by substitutions. We show that the rate of substitution in all types of coding SSRs is typically two times higher than in the rest of coding sequences. Additionally, we observe that although numerous coding SSRs are created and lost by substitutions in the lineages, their numbers remain constant. This last observation suggests that the coding SSRs have reached equilibrium. We hypothesize that this equilibrium involves a combination of mutation, drift, and selection. We thus estimated the fitness cost of mono-SSRs and show that it increases with the number of units. We finally show that the cost of coding mono-SSRs greatly varies from function to function, suggesting that the strength of the selection that acts against them can be correlated to gene functions.
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Affiliation(s)
- Etienne Loire
- UMR 7138, Systématique, Adaptation, Evolution (UPMC, CNRS, MNHN, IRD), Paris, France
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Factors influencing ascertainment bias of microsatellite allele sizes: impact on estimates of mutation rates. Genetics 2013; 195:563-72. [PMID: 23946335 DOI: 10.1534/genetics.113.154161] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microsatellite loci play an important role as markers for identification, disease gene mapping, and evolutionary studies. Mutation rate, which is of fundamental importance, can be obtained from interspecies comparisons, which, however, are subject to ascertainment bias. This bias arises, for example, when a locus is selected on the basis of its large allele size in one species (cognate species 1), in which it is first discovered. This bias is reflected in average allele length in any noncognate species 2 being smaller than that in species 1. This phenomenon was observed in various pairs of species, including comparisons of allele sizes in human and chimpanzee. Various mechanisms were proposed to explain observed differences in mean allele lengths between two species. Here, we examine the framework of a single-step asymmetric and unrestricted stepwise mutation model with genetic drift. Analysis is based on coalescent theory. Analytical results are confirmed by simulations using the simuPOP software. The mechanism of ascertainment bias in this model is a tighter correlation of allele sizes within a cognate species 1 than of allele sizes in two different species 1 and 2. We present computations of the expected average allele size difference, given the mutation rate, population sizes of species 1 and 2, time of separation of species 1 and 2, and the age of the allele. We show that when the past demographic histories of the cognate and noncognate taxa are different, the rate and directionality of mutations affect the allele sizes in the two taxa differently from the simple effect of ascertainment bias. This effect may exaggerate or reverse the effect of difference in mutation rates. We reanalyze literature data, which indicate that despite the bias, the microsatellite mutation rate estimate in the ancestral population is consistently greater than that in either human or chimpanzee and the mutation rate estimate in human exceeds or equals that in chimpanzee with the rate of allele length expansion in human being greater than that in chimpanzee. We also demonstrate that population bottlenecks and expansions in the recent human history have little impact on our conclusions.
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Mattucci F, Oliveira R, Bizzarri L, Vercillo F, Anile S, Ragni B, Lapini L, Sforzi A, Alves PC, Lyons LA, Randi E. Genetic structure of wildcat (Felis silvestris) populations in Italy. Ecol Evol 2013. [DOI: 10.1002/ece3.569] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- F. Mattucci
- Laboratorio di Genetica; ISPRA; Istituto Superiore per la Protezione e la Ricerca Ambientale; Via Cà Fornacetta 9; 40064; Ozzano dell'Emilia; Bologna; Italy
| | - R. Oliveira
- CIBIO/InBIO Laboratório Associado; Centro de Investigação em Biodiversidade e Recursos Genéticos and Dep. de Biologia da Faculdade de Ciências do Porto; Universidade do Porto; Porto; Portugal
| | - L. Bizzarri
- Dipartimento di Biologia Cellulare ed Ambientale; Università degli Studi di Perugia; Via Elce di Sotto; 06123; Perugia; Italy
| | - F. Vercillo
- Dipartimento di Biologia Cellulare ed Ambientale; Università degli Studi di Perugia; Via Elce di Sotto; 06123; Perugia; Italy
| | - S. Anile
- Dipartimento di Biologia Cellulare ed Ambientale; Università degli Studi di Perugia; Via Elce di Sotto; 06123; Perugia; Italy
| | - B. Ragni
- Dipartimento di Biologia Cellulare ed Ambientale; Università degli Studi di Perugia; Via Elce di Sotto; 06123; Perugia; Italy
| | - L. Lapini
- Museo Friulano di Storia Naturale; Via Marangoni 39; 33100; Udine; Italy
| | - A. Sforzi
- Museo di Storia Naturale della Maremma; Strada Corsini 5; 58100; Grosseto; Italy
| | | | - L. A. Lyons
- School of Veterinary Medicine; Population Health and Reproduction; University of California, Davis; One Shields Avenue; 95616; Davis; California
| | - E. Randi
- Laboratorio di Genetica; ISPRA; Istituto Superiore per la Protezione e la Ricerca Ambientale; Via Cà Fornacetta 9; 40064; Ozzano dell'Emilia; Bologna; Italy
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Alam CM, George B, Sharfuddin C, Jain S, Chakraborty S. Occurrence and analysis of imperfect microsatellites in diverse potyvirus genomes. Gene 2013; 521:238-44. [DOI: 10.1016/j.gene.2013.02.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 02/14/2013] [Accepted: 02/19/2013] [Indexed: 12/30/2022]
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Ezawa K, Landan G, Graur D. Detecting negative selection on recurrent mutations using gene genealogy. BMC Genet 2013; 14:37. [PMID: 23651527 PMCID: PMC3661350 DOI: 10.1186/1471-2156-14-37] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 04/13/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Whether or not a mutant allele in a population is under selection is an important issue in population genetics, and various neutrality tests have been invented so far to detect selection. However, detection of negative selection has been notoriously difficult, partly because negatively selected alleles are usually rare in the population and have little impact on either population dynamics or the shape of the gene genealogy. Recently, through studies of genetic disorders and genome-wide analyses, many structural variations were shown to occur recurrently in the population. Such "recurrent mutations" might be revealed as deleterious by exploiting the signal of negative selection in the gene genealogy enhanced by their recurrence. RESULTS Motivated by the above idea, we devised two new test statistics. One is the total number of mutants at a recurrently mutating locus among sampled sequences, which is tested conditionally on the number of forward mutations mapped on the sequence genealogy. The other is the size of the most common class of identical-by-descent mutants in the sample, again tested conditionally on the number of forward mutations mapped on the sequence genealogy. To examine the performance of these two tests, we simulated recurrently mutated loci each flanked by sites with neutral single nucleotide polymorphisms (SNPs), with no recombination. Using neutral recurrent mutations as null models, we attempted to detect deleterious recurrent mutations. Our analyses demonstrated high powers of our new tests under constant population size, as well as their moderate power to detect selection in expanding populations. We also devised a new maximum parsimony algorithm that, given the states of the sampled sequences at a recurrently mutating locus and an incompletely resolved genealogy, enumerates mutation histories with a minimum number of mutations while partially resolving genealogical relationships when necessary. CONCLUSIONS With their considerably high powers to detect negative selection, our new neutrality tests may open new venues for dealing with the population genetics of recurrent mutations as well as help identifying some types of genetic disorders that may have escaped identification by currently existing methods.
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Affiliation(s)
- Kiyoshi Ezawa
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
- Present address: Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan
| | - Giddy Landan
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
- Present address: Institute of Genomic Microbiology, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, Düsseldorf 40225, Germany
| | - Dan Graur
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
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Mature microsatellites: mechanisms underlying dinucleotide microsatellite mutational biases in human cells. G3-GENES GENOMES GENETICS 2013; 3:451-63. [PMID: 23450065 PMCID: PMC3583453 DOI: 10.1534/g3.112.005173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 12/30/2012] [Indexed: 12/19/2022]
Abstract
Dinucleotide microsatellites are dynamic DNA sequences that affect genome stability. Here, we focused on mature microsatellites, defined as pure repeats of lengths above the threshold and unlikely to mutate below it in a single mutational event. We investigated the prevalence and mutational behavior of these sequences by using human genome sequence data, human cells in culture, and purified DNA polymerases. Mature dinucleotides (≥10 units) are present within exonic sequences of >350 genes, resulting in vulnerability to cellular genetic integrity. Mature dinucleotide mutagenesis was examined experimentally using ex vivo and in vitro approaches. We observe an expansion bias for dinucleotide microsatellites up to 20 units in length in somatic human cells, in agreement with previous computational analyses of germ-line biases. Using purified DNA polymerases and human cell lines deficient for mismatch repair (MMR), we show that the expansion bias is caused by functional MMR and is not due to DNA polymerase error biases. Specifically, we observe that the MutSα and MutLα complexes protect against expansion mutations. Our data support a model wherein different MMR complexes shift the balance of mutations toward deletion or expansion. Finally, we show that replication fork progression is stalled within long dinucleotides, suggesting that mutational mechanisms within long repeats may be distinct from shorter lengths, depending on the biochemistry of fork resolution. Our work combines computational and experimental approaches to explain the complex mutational behavior of dinucleotide microsatellites in humans.
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Allen JM, Miyamoto MM, Wu CH, E Carter T, Ungvari-Martin J, Magrini K, Chapman CA. Primate DNA suggests long-term stability of an African rainforest. Ecol Evol 2012; 2:2829-42. [PMID: 23170217 PMCID: PMC3501634 DOI: 10.1002/ece3.395] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/27/2012] [Accepted: 09/03/2012] [Indexed: 11/07/2022] Open
Abstract
Red colobus monkeys, due to their sensitivity to environmental change, are indicator species of the overall health of their tropical rainforest habitats. As a result of habitat loss and overhunting, they are among the most endangered primates in the world, with very few viable populations remaining. Traditionally, extant indicator species have been used to signify the conditions of their current habitats, but they have also been employed to track past environmental conditions by detecting previous population fluctuations. Kibale National Park (KNP) in Uganda harbors the only remaining unthreatened large population of red colobus. We used microsatellite DNA to evaluate the historical demography of these red colobus and, therefore, the long-term stability of their habitat. We find that the red colobus population throughout KNP has been stable for at least ∼40,000 years. We interpret this result as evidence of long-term forest stability because a change in the available habitat or population movement would have elicited a corresponding change in population size. We conclude that the forest of what is now Kibale National Park may have served as a Late Pleistocene refuge for many East African species.
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Affiliation(s)
- Julie M Allen
- Florida Museum of Natural History, Dickinson Hall, Museum Road and Newell Drive, University of Florida Gainesville, Florida, 32611 ; Department of Biology, University of Florida Box 118525, Gainesville, Florida, 32611-8525
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A direct characterization of human mutation based on microsatellites. Nat Genet 2012; 44:1161-5. [PMID: 22922873 PMCID: PMC3459271 DOI: 10.1038/ng.2398] [Citation(s) in RCA: 221] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/12/2012] [Indexed: 11/08/2022]
Abstract
Mutations are the raw material of evolution, but have been difficult to study directly. We report the largest study of new mutations to date: 2,058 germline changes discovered by analyzing 85,289 Icelanders at 2,477 microsatellites. The paternal-to-maternal mutation rate ratio is 3.3, and the rate in fathers doubles from age 20 to 58 whereas there is no association with age in mothers. Longer microsatellite alleles are more mutagenic and tend to decrease in length, whereas the opposite is seen for shorter alleles. We use these empirical observations to build a model that we apply to individuals for whom we have both genome sequence and microsatellite data, allowing us to estimate key parameters of evolution without calibration to the fossil record. We infer that the sequence mutation rate is 1.4–2.3×10−8 per base pair per generation (90% credible interval), and that human-chimpanzee speciation occurred 3.7–6.6 million years ago.
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Fondon JW, Martin A, Richards S, Gibbs RA, Mittelman D. Analysis of microsatellite variation in Drosophila melanogaster with population-scale genome sequencing. PLoS One 2012; 7:e33036. [PMID: 22427938 PMCID: PMC3299726 DOI: 10.1371/journal.pone.0033036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 02/07/2012] [Indexed: 11/29/2022] Open
Abstract
Genome sequencing technologies promise to revolutionize our understanding of genetics, evolution, and disease by making it feasible to survey a broad spectrum of sequence variation on a population scale. However, this potential can only be realized to the extent that methods for extracting and interpreting distinct forms of variation can be established. The error profiles and read length limitations of early versions of next-generation sequencing technologies rendered them ineffective for some sequence variant types, particularly microsatellites and other tandem repeats, and fostered the general misconception that such variants are inherently inaccessible to these platforms. At the same time, tandem repeats have emerged as important sources of functional variation. Tandem repeats are often located in and around genes, and frequent mutations in their lengths exert quantitative effects on gene function and phenotype, rapidly degrading linkage disequilibrium between markers and traits. Sensitive identification of these variants in large-scale next-gen sequencing efforts will enable more comprehensive association studies capable of revealing previously invisible associations. We present a population-scale analysis of microsatellite repeats using whole-genome data from 158 inbred isolates from the Drosophila Genetics Reference Panel, a collection of over 200 extensively phenotypically characterized isolates from a single natural population, to uncover processes underlying repeat mutation and to enable associations with behavioral, morphological, and life-history traits. Analysis of repeat variation from next-generation sequence data will also enhance studies of genome stability and neurodegenerative diseases.
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Affiliation(s)
- John W. Fondon
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Andy Martin
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Stephen Richards
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard A. Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - David Mittelman
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
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Jan C, Dawson DA, Altringham JD, Burke T, Butlin RK. Development of conserved microsatellite markers of high cross-species utility in bat species (Vespertilionidae, Chiroptera, Mammalia). Mol Ecol Resour 2012; 12:532-48. [PMID: 22260443 DOI: 10.1111/j.1755-0998.2012.03114.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Comparative ecological and behavioural studies of the widespread and diverse Vespertilionidae, which comprise almost 400 of the 1100 bat species, have been limited by the availability of markers. The potential of new methods for developing conserved microsatellite markers that possess enhanced cross-species utility has recently been illustrated in studies of birds. We have applied these methods to develop enhanced microsatellite markers for vespertilionid bats, in particular for the genus Myotis (103 species). We compared published bat microsatellites with their homologues in the genome sequence of the little brown bat, Myotis lucifugus, to create consensus sequences that were used to design candidate primer sets. Primer sets were then tested for amplification and polymorphism in 22 species of bat from nine of the largest families (including 11 Vespertilionidae). Of 46 loci tested, 33 were polymorphic, on average, in each of seven Myotis species tested, 20 in each of four species in other vespertilionid genera, and two in 11 nonvespertilionid species.
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Affiliation(s)
- Camille Jan
- Institute of Integrative and Comparative Biology University of Leeds, Leeds LS2 9JT, UK
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Design and implementation of degenerate microsatellite primers for the mammalian clade. PLoS One 2011; 6:e29582. [PMID: 22216321 PMCID: PMC3246486 DOI: 10.1371/journal.pone.0029582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 12/01/2011] [Indexed: 11/19/2022] Open
Abstract
Microsatellites are popular genetic markers in molecular ecology, genetic mapping and forensics. Unfortunately, despite recent advances, the isolation of de novo polymorphic microsatellite loci often requires expensive and intensive groundwork. Primers developed for a focal species are commonly tested in a related, non-focal species of interest for the amplification of orthologous polymorphic loci; when successful, this approach significantly reduces cost and time of microsatellite development. However, transferability of polymorphic microsatellite loci decreases rapidly with increasing evolutionary distance, and this approach has shown its limits. Whole genome sequences represent an under-exploited resource to develop cross-species primers for microsatellites. Here we describe a three-step method that combines a novel in silico pipeline that we use to (1) identify conserved microsatellite loci from a multiple genome alignments, (2) design degenerate primer pairs, with (3) a simple PCR protocol used to implement these primers across species. Using this approach we developed a set of primers for the mammalian clade. We found 126,306 human microsatellites conserved in mammalian aligned sequences, and isolated 5,596 loci using criteria based on wide conservation. From a random subset of ~1000 dinucleotide repeats, we designed degenerate primer pairs for 19 loci, of which five produced polymorphic fragments in up to 18 mammalian species, including the distinctly related marsupials and monotremes, groups that diverged from other mammals 120-160 million years ago. Using our method, many more cross-clade microsatellite loci can be harvested from the currently available genomic data, and this ability is set to improve exponentially as further genomes are sequenced.
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Chaturvedi A, Mohindra V, Singh RK, Lal KK, Punia P, Bhaskar R, Mandal A, Narain L, Lakra WS. Population genetic structure and phylogeography of cyprinid fish, Labeo dero (Hamilton, 1822) inferred from allozyme and microsatellite DNA marker analysis. Mol Biol Rep 2011; 38:3513-29. [PMID: 21132388 DOI: 10.1007/s11033-010-0462-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We examined population structure of Labeo dero (Hamilton, 1822) from different riverine locations in India using 10 polymorphic allozyme and eight microsatellite loci. For analysis, 591 different tissue samples were obtained from commercial catches covering a wide geographic range. Allozyme variability (An = 1.28-1.43, Ho = 0.029-0.071) was much lower than for microsatellites (An = 4.625-6.125, Ho = 0.538-0.633). Existence of rare alleles was found at three allozyme (MDH-2, GPI and PGDH) and at two microsatellite loci (R-3 and MFW-15). Deviation from Hardy-Weinberg equilibrium (P < 0.05, after the critical probability levels were adjusted for sequential Bonferroni adjustment) could be detected at three loci (EST-1, -2 and XDH) whereas, after correction for null alleles, two microsatellite loci (MFW-1,-15) deviated from HWE in the river Yamuna. Fst for all the samples combined over all allozyme loci was found to be 0.059 suggesting that 5.9% of the total variation was due to genetic differentiation while microsatellite analysis yielded 0.019 which was concordant to mean Rst (0.02). Hierarchical partition of genetic diversity (AMOVA) showed that greater variability (approx. 95%) was due to within population component than between geographical regions. Based on distribution of genetic differentiation detected by both markers, at least five different genetic stocks of L. dero across its natural distribution could be identified. These results are useful for the evaluation and conservation of L. dero in natural water bodies.
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Affiliation(s)
- Anshumala Chaturvedi
- National Bureau of Fish Genetic Resources (ICAR), Canal Ring Road, P.O. Dilkusha, Lucknow, 226 002 UP, India
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Empirical evaluation reveals best fit of a logistic mutation model for human Y-chromosomal microsatellites. Genetics 2011; 189:1403-11. [PMID: 21968190 DOI: 10.1534/genetics.111.132308] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The rate of microsatellite mutation is dependent upon both the allele length and the repeat motif, but the exact nature of this relationship is still unknown. We analyzed data on the inheritance of human Y-chromosomal microsatellites in father-son duos, taken from 24 published reports and comprising 15,285 directly observable meioses. At the six microsatellites analyzed (DYS19, DYS389I, DYS390, DYS391, DYS392, and DYS393), a total of 162 mutations were observed. For each locus, we employed a maximum-likelihood approach to evaluate one of several single-step mutation models on the basis of the data. For five of the six loci considered, a novel logistic mutation model was found to provide the best fit according to Akaike's information criterion. This implies that the mutation probability at the loci increases (nonlinearly) with allele length at a rate that differs between upward and downward mutations. For DYS392, the best fit was provided by a linear model in which upward and downward mutation probabilities increase equally with allele length. This is the first study to empirically compare different microsatellite mutation models in a locus-specific fashion.
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42
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Evaluating the reliability of microsatellite genotyping from low-quality DNA templates with a polynomial distribution model. CHINESE SCIENCE BULLETIN-CHINESE 2011. [DOI: 10.1007/s11434-011-4634-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Jighly A, Hamwieh A, Ogbonnaya FC. Optimization of sequence alignment for simple sequence repeat regions. BMC Res Notes 2011; 4:239. [PMID: 21774810 PMCID: PMC3160389 DOI: 10.1186/1756-0500-4-239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 07/20/2011] [Indexed: 11/13/2022] Open
Abstract
Background Microsatellites, or simple sequence repeats (SSRs), are tandemly repeated DNA sequences, including tandem copies of specific sequences no longer than six bases, that are distributed in the genome. SSR has been used as a molecular marker because it is easy to detect and is used in a range of applications, including genetic diversity, genome mapping, and marker assisted selection. It is also very mutable because of slipping in the DNA polymerase during DNA replication. This unique mutation increases the insertion/deletion (INDELs) mutation frequency to a high ratio - more than other types of molecular markers such as single nucleotide polymorphism (SNPs). SNPs are more frequent than INDELs. Therefore, all designed algorithms for sequence alignment fit the vast majority of the genomic sequence without considering microsatellite regions, as unique sequences that require special consideration. The old algorithm is limited in its application because there are many overlaps between different repeat units which result in false evolutionary relationships. Findings To overcome the limitation of the aligning algorithm when dealing with SSR loci, a new algorithm was developed using PERL script with a Tk graphical interface. This program is based on aligning sequences after determining the repeated units first, and the last SSR nucleotides positions. This results in a shifting process according to the inserted repeated unit type. When studying the phylogenic relations before and after applying the new algorithm, many differences in the trees were obtained by increasing the SSR length and complexity. However, less distance between different linage had been observed after applying the new algorithm. Conclusions The new algorithm produces better estimates for aligning SSR loci because it reflects more reliable evolutionary relations between different linages. It reduces overlapping during SSR alignment, which results in a more realistic phylogenic relationship.
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Affiliation(s)
- Abdulqader Jighly
- International Center for Agricultural Research in the Dry Areas (ICARDA), P,O, Box 5466, Aleppo, Syria.
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Joint inference of microsatellite mutation models, population history and genealogies using transdimensional Markov Chain Monte Carlo. Genetics 2011; 188:151-64. [PMID: 21385725 PMCID: PMC3120151 DOI: 10.1534/genetics.110.125260] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We provide a framework for Bayesian coalescent inference from microsatellite data that enables inference of population history parameters averaged over microsatellite mutation models. To achieve this we first implemented a rich family of microsatellite mutation models and related components in the software package BEAST. BEAST is a powerful tool that performs Bayesian MCMC analysis on molecular data to make coalescent and evolutionary inferences. Our implementation permits the application of existing nonparametric methods to microsatellite data. The implemented microsatellite models are based on the replication slippage mechanism and focus on three properties of microsatellite mutation: length dependency of mutation rate, mutational bias toward expansion or contraction, and number of repeat units changed in a single mutation event. We develop a new model that facilitates microsatellite model averaging and Bayesian model selection by transdimensional MCMC. With Bayesian model averaging, the posterior distributions of population history parameters are integrated across a set of microsatellite models and thus account for model uncertainty. Simulated data are used to evaluate our method in terms of accuracy and precision of θ estimation and also identification of the true mutation model. Finally we apply our method to a red colobus monkey data set as an example.
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Ballantyne KN, Goedbloed M, Fang R, Schaap O, Lao O, Wollstein A, Choi Y, van Duijn K, Vermeulen M, Brauer S, Decorte R, Poetsch M, von Wurmb-Schwark N, de Knijff P, Labuda D, Vézina H, Knoblauch H, Lessig R, Roewer L, Ploski R, Dobosz T, Henke L, Henke J, Furtado MR, Kayser M. Mutability of Y-chromosomal microsatellites: rates, characteristics, molecular bases, and forensic implications. Am J Hum Genet 2010; 87:341-53. [PMID: 20817138 DOI: 10.1016/j.ajhg.2010.08.006] [Citation(s) in RCA: 271] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 08/02/2010] [Accepted: 08/13/2010] [Indexed: 11/24/2022] Open
Abstract
Nonrecombining Y-chromosomal microsatellites (Y-STRs) are widely used to infer population histories, discover genealogical relationships, and identify males for criminal justice purposes. Although a key requirement for their application is reliable mutability knowledge, empirical data are only available for a small number of Y-STRs thus far. To rectify this, we analyzed a large number of 186 Y-STR markers in nearly 2000 DNA-confirmed father-son pairs, covering an overall number of 352,999 meiotic transfers. Following confirmation by DNA sequence analysis, the retrieved mutation data were modeled via a Bayesian approach, resulting in mutation rates from 3.78 × 10(-4) (95% credible interval [CI], 1.38 × 10(-5) - 2.02 × 10(-3)) to 7.44 × 10(-2) (95% CI, 6.51 × 10(-2) - 9.09 × 10(-2)) per marker per generation. With the 924 mutations at 120 Y-STR markers, a nonsignificant excess of repeat losses versus gains (1.16:1), as well as a strong and significant excess of single-repeat versus multirepeat changes (25.23:1), was observed. Although the total repeat number influenced Y-STR locus mutability most strongly, repeat complexity, the length in base pairs of the repeated motif, and the father's age also contributed to Y-STR mutability. To exemplify how to practically utilize this knowledge, we analyzed the 13 most mutable Y-STRs in an independent sample set and empirically proved their suitability for distinguishing close and distantly related males. This finding is expected to revolutionize Y-chromosomal applications in forensic biology, from previous male lineage differentiation toward future male individual identification.
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Caliebe A, Jochens A, Krawczak M, Rösler U. A Markov chain description of the stepwise mutation model: Local and global behaviour of the allele process. J Theor Biol 2010; 266:336-42. [DOI: 10.1016/j.jtbi.2010.06.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 06/24/2010] [Accepted: 06/24/2010] [Indexed: 11/25/2022]
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Mutation biases and mutation rate variation around very short human microsatellites revealed by human-chimpanzee-orangutan genomic sequence alignments. J Mol Evol 2010; 71:192-201. [PMID: 20700734 DOI: 10.1007/s00239-010-9377-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 07/26/2010] [Indexed: 01/21/2023]
Abstract
I have studied mutation patterns around very short microsatellites, focusing mainly on sequences carrying only two repeat units. By using human-chimpanzee-orangutan alignments, inferences can be made about both the relative rates of mutations and which bases have mutated. I find remarkable non-randomness, with mutation rate depending on a base's position relative to the microsatellite, the identity of the base itself and the motif in the microsatellite. Comparing the patterns around AC2 with those around other four-base combinations reveals that AC2 does not stand out as being special in the sense that non-repetitive tetramers also generate strong mutation biases. However, comparing AC2 and AC3 with AC4 reveals a step change in both the rate and nature of mutations occurring, suggesting a transition state, AC4 exhibiting an alternating high-low mutation rate pattern consistent with the sequence patterning seen around longer microsatellites. Surprisingly, most changes in repeat number occur through base substitutions rather than slippage, and the relative probability of gaining versus losing a repeat in this way varies greatly with repeat number. Slippage mutations reveal rather similar patterns of mutability compared with point mutations, being rare at two repeats where most cause the loss of a repeat, with both mutation rate and the proportion of expansion mutations increasing up to 6-8 repeats. Inferences about longer repeat tracts are hampered by uncertainties about the proportion of multi-species alignments that fail due to multi-repeat mutations and other rearrangements.
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Payseur BA, Jing P, Haasl RJ. A genomic portrait of human microsatellite variation. Mol Biol Evol 2010; 28:303-12. [PMID: 20675409 DOI: 10.1093/molbev/msq198] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rapid advances in DNA sequencing and genotyping technologies are beginning to reveal the scope and pattern of human genomic variation. Although single nucleotide polymorphisms (SNPs) have been intensively studied, the extent and form of variation at other types of molecular variants remain poorly understood. Polymorphism at the most variable loci in the human genome, microsatellites, has rarely been examined on a genomic scale without the ascertainment biases that attend typical genotyping studies. We conducted a genomic survey of variation at microsatellites with at least three perfect repeats by comparing two complete genome sequences, the Human Genome Reference sequence and the sequence of J. Craig Venter. The genomic proportion of polymorphic loci was 2.7%, much higher than the rate of SNP variation, with marked heterogeneity among classes of loci. The proportion of variable loci increased substantially with repeat number. Repeat lengths differed in levels of variation, with longer repeat lengths generally showing higher polymorphism at the same repeat number. Microsatellite variation was weakly correlated with regional SNP number, indicating modest effects of shared genealogical history. Reductions in variation were detected at microsatellites located in introns, in untranslated regions, in coding exons, and just upstream of transcription start sites, suggesting the presence of selective constraints. Our results provide new insights into microsatellite mutational processes and yield a preview of patterns of variation that will be obtained in genomic surveys of larger numbers of individuals.
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Leclercq S, Rivals E, Jarne P. DNA slippage occurs at microsatellite loci without minimal threshold length in humans: a comparative genomic approach. Genome Biol Evol 2010; 2:325-35. [PMID: 20624737 PMCID: PMC2997547 DOI: 10.1093/gbe/evq023] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The dynamics of microsatellite, or short tandem repeats (STRs), is well documented for long, polymorphic loci, but much less is known for shorter ones. For example, the issue of a minimum threshold length for DNA slippage remains contentious. Model-fitting methods have generally concluded that slippage only occurs over a threshold length of about eight nucleotides, in contradiction with some direct observations of tandem duplications at shorter repeated sites. Using a comparative analysis of the human and chimpanzee genomes, we examined the mutation patterns at microsatellite loci with lengths as short as one period plus one nucleotide. We found that the rates of tandem insertions and deletions at microsatellite loci strongly deviated from background rates in other parts of the human genome and followed an exponential increase with STR size. More importantly, we detected no lower threshold length for slippage. The rate of tandem duplications at unrepeated sites was higher than expected from random insertions, providing evidence for genome-wide action of indel slippage (an alternative mechanism generating tandem repeats). The rate of point mutations adjacent to STRs did not differ from that estimated elsewhere in the genome, except around dinucleotide loci. Our results suggest that the emergence of STR depends on DNA slippage, indel slippage, and point mutations. We also found that the dynamics of tandem insertions and deletions differed in both rates and size at which these mutations take place. We discuss these results in both evolutionary and mechanistic terms.
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Affiliation(s)
- Sébastien Leclercq
- Centre d'Ecologie Fonctionnelle et d'Evolution, UMR 5175 CNRS, 1919 route de Mende, 34095 Montpellier cedex 5, France.
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