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Molecular insights into the invasion dynamics of Carcinus crabs in South Africa. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02865-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
AbstractKnowledge of the introduction history and spread dynamics of invasive species can provide important insights for management (Ens et al. in Environ Rev (in press), 2022), however such information is often unavailable for accidental introductions. Here we infer how the European shore crab, Carcinus maenas, and its congener, the Mediterranean shore crab, C. aestuarii, were introduced to and spread within South Africa. We do this using nuclear microsatellite data and Bayesian assignment tests and Approximate Bayesian Computation (ABC) modelling that included samples from the native and other invasive ranges of these two species. We also compared the genetic diversity and structure of one of the South African populations during and after intensive management, with that of another, unmanaged, population. South African populations had higher genetic diversity than invasive Carcinus populations from elsewhere in the world. Moreover, the ABC analyses suggest that South African populations originated from an admixture event between individuals of C. maenas from a population in the native range and an invasive population from Canada. We also identified instances of hybridisation between Carcinus maenas and C. aestuarii in South Africa. South African populations showed no genetic structure, suggesting either extensive migration between them or that populations arose from the same initial introduction. Management of Carcinus did not affect genetic diversity or structure, and we suspect that the management duration was insufficient to target a full generation of crabs. Together these results suggest multiple introductions and/or high propagule pressure to South Africa, crab (larval or adult) movement between existing populations, and some hybridisation. For eradication from South Africa to be achieved, management would need to concurrently target all known invasive populations and clearly establish that new introductions could be prevented.
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Mongue AJ, Michaelides S, Coombe O, Tena A, Kim DS, Normark BB, Gardner A, Hoddle MS, Ross L. Sex, males, and hermaphrodites in the scale insect Icerya purchasi. Evolution 2021; 75:2972-2983. [PMID: 33844310 DOI: 10.1111/evo.14233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 11/30/2022]
Abstract
Androdioecy (the coexistence of males and hermaphrodites) is a rare mating system for which the evolutionary dynamics are poorly understood. Here, we investigate the cottony cushion scale, Icerya purchasi, one of only three reported cases of androdioecy in insects. In this species, female-like hermaphrodites have been shown to produce sperm and self-fertilize. However, males are ocassionally observed as well. In a large genetic analysis, we show for the first time that, although self-fertilization appears to be the primary mode of reproduction, rare outbreeding events do occur in natural populations, supporting the hypothesis that hermaphrodites mate with males and hence androdioecy is the mating system of I. purchasi. Thus, this globally invasive pest insect appears to enjoy the colonization advantages of a selfing organism while also benefitting from periodic reintroduction of genetic variation through outbreeding with males.
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Affiliation(s)
- Andrew J Mongue
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
| | - Sozos Michaelides
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,Department of Biology, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | - Oliver Coombe
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom
| | - Alejandro Tena
- Institut Valencià d'Investigacions Agràries (IVIA), Centre de Protecció Vegetal i Biotecnologia, Unitat d'Entomologia, Moncada, 46113, Spain
| | - Dong-Soon Kim
- Majors in Plant Resource Sciences and Environment, College of Applied Life Science, SARI, Jeju National University, Jeju, 63243, Republic of Korea
| | - Benjamin B Normark
- Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Andy Gardner
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,School of Biology, University of St Andrews, Fife, KY16 9TH, United Kingdom
| | - Mark S Hoddle
- Department of Entomology, University of California, Riverside, California, 92521
| | - Laura Ross
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom.,Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003
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3
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Are Microsatellite Patterns Specific for Tumor Types? A Pilot Investigation. JOURNAL OF MOLECULAR PATHOLOGY 2020. [DOI: 10.3390/jmp1010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Microsatellite testing is an emerging field of molecular pathology, as microsatellite instability (MSI) appears to be a predictive biomarker for some cancers. Although multiple studies on microsatellites have been published, recent observations suggest that the microsatellites that define instability differ between tumor entities. This assumption is confirmed by the present study that compared different MSI assays validated for colorectal cancer. Whilst all assays deliver the same MSI/MSS status for colorectal cancers, they differ for tonsillar tumors, leading to the hypothesis that MSI patterns are tumor-type specific.
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McDew-White M, Li X, Nkhoma SC, Nair S, Cheeseman I, Anderson TJC. Mode and Tempo of Microsatellite Length Change in a Malaria Parasite Mutation Accumulation Experiment. Genome Biol Evol 2020; 11:1971-1985. [PMID: 31273388 PMCID: PMC6644851 DOI: 10.1093/gbe/evz140] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2019] [Indexed: 12/12/2022] Open
Abstract
Malaria parasites have small extremely AT-rich genomes: microsatellite repeats (1–9 bp) comprise 11% of the genome and genetic variation in natural populations is dominated by repeat changes in microsatellites rather than point mutations. This experiment was designed to quantify microsatellite mutation patterns in Plasmodium falciparum. We established 31 parasite cultures derived from a single parasite cell and maintained these for 114–267 days with frequent reductions to a single cell, so parasites accumulated mutations during ∼13,207 cell divisions. We Illumina sequenced the genomes of both progenitor and end-point mutation accumulation (MA) parasite lines in duplicate to validate stringent calling parameters. Microsatellite calls were 99.89% (GATK), 99.99% (freeBayes), and 99.96% (HipSTR) concordant in duplicate sequence runs from independent sequence libraries, whereas introduction of microsatellite mutations into the reference genome revealed a low false negative calling rate (0.68%). We observed 98 microsatellite mutations. We highlight several conclusions: microsatellite mutation rates (3.12 × 10−7 to 2.16 × 10−8/cell division) are associated with both repeat number and repeat motif like other organisms studied. However, 41% of changes resulted from loss or gain of more than one repeat: this was particularly true for long repeat arrays. Unlike other eukaryotes, we found no insertions or deletions that were not associated with repeats or homology regions. Overall, microsatellite mutation rates are among the lowest recorded and comparable to those in another AT-rich protozoan (Dictyostelium). However, a single infection (>1011 parasites) will still contain over 2.16 × 103 to 3.12 × 104 independent mutations at any single microsatellite locus.
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Affiliation(s)
| | - Xue Li
- Texas Biomedical Research Institute, San Antonio, Texas
| | - Standwell C Nkhoma
- Texas Biomedical Research Institute, San Antonio, Texas.,Malaria Research and Reference Reagent Resource Center (MR4), BEI Resources, American Type Culture Collection, 10801 University Boulevard, Manassas, VA
| | - Shalini Nair
- Texas Biomedical Research Institute, San Antonio, Texas
| | - Ian Cheeseman
- Texas Biomedical Research Institute, San Antonio, Texas
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Kurata S, Sakaguchi S, Ito M. Genetic diversity and population demography of Geranium soboliferum var. kiusianum: a glacial relict plant in the wetlands of Japan. CONSERV GENET 2019. [DOI: 10.1007/s10592-018-01141-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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6
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O’Reilly GD, Jabot F, Gunn MR, Sherwin WB. Predicting Shannon’s information for genes in finite populations: new uses for old equations. CONSERV GENET RESOUR 2018. [DOI: 10.1007/s12686-018-1079-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Watts PC, Kallio ER, Koskela E, Lonn E, Mappes T, Mokkonen M. Stabilizing selection on microsatellite allele length at arginine vasopressin 1a receptor and oxytocin receptor loci. Proc Biol Sci 2017; 284:rspb.2017.1896. [PMID: 29237850 PMCID: PMC5745408 DOI: 10.1098/rspb.2017.1896] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/13/2017] [Indexed: 12/27/2022] Open
Abstract
The loci arginine vasopressin receptor 1a (avpr1a) and oxytocin receptor (oxtr) have evolutionarily conserved roles in vertebrate social and sexual behaviour. Allelic variation at a microsatellite locus in the 5′ regulatory region of these genes is associated with fitness in the bank vole Myodes glareolus. Given the low frequency of long and short alleles at these microsatellite loci in wild bank voles, we used breeding trials to determine whether selection acts against long and short alleles. Female bank voles with intermediate length avpr1a alleles had the highest probability of breeding, while male voles whose avpr1a alleles were very different in length had reduced probability of breeding. Moreover, there was a significant interaction between male and female oxtr genotypes, where potential breeding pairs with dissimilar length alleles had reduced probability of breeding. These data show how genetic variation at microsatellite loci associated with avpr1a and oxtr is associated with fitness, and highlight complex patterns of selection at these loci. More widely, these data show how stabilizing selection might act on allele length frequency distributions at gene-associated microsatellite loci.
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Affiliation(s)
- Phillip C Watts
- Department of Ecology and Genetics, University of Oulu, Oulu 90014, Finland .,Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland
| | - Eva R Kallio
- Department of Ecology and Genetics, University of Oulu, Oulu 90014, Finland.,Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland
| | - Eija Lonn
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland
| | - Mikael Mokkonen
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland.,Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A1S6
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Cabrera AA, Palsbøll PJ. Inferring past demographic changes from contemporary genetic data: A simulation-based evaluation of the ABC methods implemented indiyabc. Mol Ecol Resour 2017; 17:e94-e110. [DOI: 10.1111/1755-0998.12696] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 06/12/2017] [Accepted: 06/20/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Andrea A. Cabrera
- Marine Evolution and Conservation; Groningen Institute of Evolutionary Life Sciences; University of Groningen; Groningen The Netherlands
| | - Per J. Palsbøll
- Marine Evolution and Conservation; Groningen Institute of Evolutionary Life Sciences; University of Groningen; Groningen The Netherlands
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Hoffman JI, Kowalski GJ, Klimova A, Eberhart-Phillips LJ, Staniland IJ, Baylis AMM. Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160291. [PMID: 27493782 PMCID: PMC4968474 DOI: 10.1098/rsos.160291] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations.
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Affiliation(s)
- J. I. Hoffman
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
| | - G. J. Kowalski
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
- Animal Ecology Group, Institute of Biochemistry and Biology, University of Potsdam, Maulbeerallee 1, 14469, Potsdam, Germany
| | - A. Klimova
- Centro de Investigaciones Biológicas del Noroeste Baja California Sur, La Paz, Mexico
| | - L. J. Eberhart-Phillips
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
| | - I. J. Staniland
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - A. M. M. Baylis
- South Atlantic Environmental Research Institute, Stanley FIQQ1ZZ, Falkland Islands
- Falklands Conservation, Stanley FIQQ1ZZ, Falkland Islands
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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10
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Chapuis MP, Plantamp C, Streiff R, Blondin L, Piou C. Microsatellite evolutionary rate and pattern in Schistocerca gregaria inferred from direct observation of germline mutations. Mol Ecol 2015; 24:6107-19. [PMID: 26562076 DOI: 10.1111/mec.13465] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 01/21/2023]
Abstract
Unravelling variation among taxonomic orders regarding the rate of evolution in microsatellites is crucial for evolutionary biology and population genetics research. The mean mutation rate of microsatellites tends to be lower in arthropods than in vertebrates, but data are scarce and mostly concern accumulation of mutations in model species. Based on parent-offspring segregations and a hierarchical Bayesian model, the mean rate of mutation in the orthopteran insect Schistocerca gregaria was estimated at 2.1e(-4) per generation per untranscribed dinucleotide locus. This is close to vertebrate estimates and one order of magnitude higher than estimates from species of other arthropod orders, such as Drosophila melanogaster and Daphnia pulex. We also found evidence of a directional bias towards expansions even for long alleles and exceptionally large ranges of allele sizes. Finally, at transcribed microsatellites, the mean rate of mutation was half the rate found at untranscribed loci and the mutational model deviated from that usually considered, with most mutations involving multistep changes that avoid disrupting the reading frame. Our direct estimates of mutation rate were discussed in the light of peculiar biological and genomic features of S. gregaria, including specificities in mismatch repair and the dependence of its activity to allele length. Shedding new light on the mutational dynamics of grasshopper microsatellites is of critical importance for a number of research fields. As an illustration, we showed how our findings improve microsatellite application in population genetics, by obtaining a more precise estimation of S. gregaria effective population size from a published data set based on the same microsatellites.
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Affiliation(s)
- M-P Chapuis
- CIRAD, UMR CBGP, Montpellier, F-34398, France
| | - C Plantamp
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, Villeurbanne, 69622, France
| | - R Streiff
- INRA, UMR CBGP, Montpellier, F-34398, France.,INRA, UMR DGIMI, Montpellier, F-34000, France
| | - L Blondin
- CIRAD, UPR B-AMR, Montpellier, F-34398, France
| | - C Piou
- CIRAD, UMR CBGP, Montpellier, F-34398, France
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11
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Cheng X, Chai L, Chen Z, Xu L, Zhai H, Zhao A, Peng H, Yao Y, You M, Sun Q, Ni Z. Identification and characterization of a high kernel weight mutant induced by gamma radiation in wheat (Triticum aestivum L.). BMC Genet 2015; 16:127. [PMID: 26511975 PMCID: PMC4625876 DOI: 10.1186/s12863-015-0285-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/21/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Inducing mutations are considered to be an effective way to create novel genetic variations and hence novel agronomical traits in wheat. This study was conducted to assess the genetic differences between Shi4185 and its mutant line Fu4185, produced by gamma radiation with larger grain, and to identify quantitative trait loci (QTLs) for thousand kernel weight (TKW). RESULTS Phenotypic analysis revealed that the TKW of Fu4185 was much higher than that of Shi4185 under five different environments. At the genomic level, 110 of 2019 (5.4%) simple sequence repeats (SSR) markers showed polymorphism between Shi4185 and Fu4185. Notably, 30% (33 out of 110) polymorphic SSR markers were located on the D-genome, which was higher than the percentage of polymorphisms among natural allohexaploid wheat genotypes, indicating that mutations induced by gamma radiation could be a potential resource to enrich the genetic diversity of wheat D-genome. Moreover, one QTL, QTkw.cau-5D, located on chromosome 5DL, with Fu4185 contributing favorable alleles, was detected under different environments, especially under high temperature conditions. CONCLUSIONS QTkw.cau-5D is an environmental stable QTL, which may be a desired target for genetic improvement of wheat kernel weight.
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Affiliation(s)
- Xuejiao Cheng
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Lingling Chai
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Zhaoyan Chen
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Lu Xu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Huijie Zhai
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Aiju Zhao
- Hebei Crop Genetic Breeding Laboratory Institute of Cereal and Oil Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, 050035, China.
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Mingshan You
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Yuanmingyuan Xi Road No. 2, Haidian District, Beijing, 100193, China.
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China.
- National Plant Gene Research Centre, Beijing, 100193, China.
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12
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Broad-scale genetic patterns of New Zealand abalone, Haliotis iris, across a distribution spanning 13° latitude and major oceanic water masses. Genetica 2015; 143:487-500. [PMID: 26050219 DOI: 10.1007/s10709-015-9847-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 05/30/2015] [Indexed: 10/23/2022]
Abstract
The New Zealand black-foot abalone, Haliotis iris, or pāua, is endemic to the rocky reefs surrounding New Zealand, whose main land mass spans 13° of latitude and separates the Tasman Sea from the Pacific Ocean. In this study, we examined the population genetic structure of this important commercial, cultural and recreational species by genotyping nine microsatellite loci in 485 pāua from 27 locations distributed across mainland New Zealand and the Chatham Islands. We found low, but significant, levels of genetic differentiation. Key genetic breaks were identified among the Chatham Islands and mainland samples; patterns that are strongly corroborated by prior work employing mtDNA sequences. AMOVAs indicated that samples from the south of the North Island were more similar to the South Island samples than to other North Island samples, however multivariate analysis and Bayesian clustering could not identify a significant pattern. Differentiation between the Chatham Islands and the mainland is most likely due to isolation by distance, while differentiation of North Island samples corresponds with major components of New Zealand's oceanography, Cook Strait and the East Cape. Despite intense fishing pressure, we detected no signature of genetic bottlenecks in any region suggesting that population sizes have remained relatively stable over recent time or that the census size of this species is much larger than its effective population size.
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13
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Development of chromosome-specific markers with high polymorphism for allotetraploid cotton based on genome-wide characterization of simple sequence repeats in diploid cottons (Gossypium arboreum L. and Gossypium raimondii Ulbrich). BMC Genomics 2015; 16:55. [PMID: 25652321 PMCID: PMC4325953 DOI: 10.1186/s12864-015-1265-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/22/2015] [Indexed: 02/04/2023] Open
Abstract
Background Tetraploid cotton contains two sets of homologous chromosomes, the At- and Dt-subgenomes. Consequently, many markers in cotton were mapped to multiple positions during linkage genetic map construction, posing a challenge to anchoring linkage groups and mapping economically-important genes to particular chromosomes. Chromosome-specific markers could solve this problem. Recently, the genomes of two diploid species were sequenced whose progenitors were putative contributors of the At- and Dt-subgenomes to tetraploid cotton. These sequences provide a powerful tool for developing chromosome-specific markers given the high level of synteny among tetraploid and diploid cotton genomes. In this study, simple sequence repeats (SSRs) on each chromosome in the two diploid genomes were characterized. Chromosome-specific SSRs were developed by comparative analysis and proved to distinguish chromosomes. Results A total of 200,744 and 142,409 SSRs were detected on the 13 chromosomes of Gossypium arboreum L. and Gossypium raimondii Ulbrich, respectively. Chromosome-specific SSRs were obtained by comparing SSR flanking sequences from each chromosome with those from the other 25 chromosomes. The average was 7,996 per chromosome. To confirm their chromosome specificity, these SSRs were used to distinguish two homologous chromosomes in tetraploid cotton through linkage group construction. The chromosome-specific SSRs and previously-reported chromosome markers were grouped together, and no marker mapped to another homologous chromosome, proving that the chromosome-specific SSRs were unique and could distinguish homologous chromosomes in tetraploid cotton. Because longer dinucleotide AT-rich repeats were the most polymorphic in previous reports, the SSRs on each chromosome were sorted by motif type and repeat length for convenient selection. The primer sequences of all chromosome-specific SSRs were also made publicly available. Conclusion Chromosome-specific SSRs are efficient tools for chromosome identification by anchoring linkage groups to particular chromosomes during genetic mapping and are especially useful in mapping of qualitative-trait genes or quantitative trait loci with just a few markers. The SSRs reported here will facilitate a number of genetic and genomic studies in cotton, including construction of high-density genetic maps, positional gene cloning, fingerprinting, and genetic diversity and comparative evolutionary analyses among Gossypium species. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1265-2) contains supplementary material, which is available to authorized users.
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Klimova A, Munguia-Vega A, Hoffman JI, Culver M. Genetic diversity and demography of two endangered captive pronghorn subspecies from the Sonoran Desert. J Mammal 2014. [DOI: 10.1644/13-mamm-a-321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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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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Kraus RHS, vonHoldt B, Cocchiararo B, Harms V, Bayerl H, Kühn R, Förster DW, Fickel J, Roos C, Nowak C. A single-nucleotide polymorphism-based approach for rapid and cost-effective genetic wolf monitoring in Europe based on noninvasively collected samples. Mol Ecol Resour 2014; 15:295-305. [DOI: 10.1111/1755-0998.12307] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 07/11/2014] [Accepted: 07/16/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Robert H. S. Kraus
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; D-63571 Gelnhausen Germany
| | - Bridgett vonHoldt
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
| | - Berardino Cocchiararo
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; D-63571 Gelnhausen Germany
| | - Verena Harms
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; D-63571 Gelnhausen Germany
- Senckenberg Museum of Natural History Görlitz; PF 300154 02806 Görlitz Germany
| | - Helmut Bayerl
- Molecular Zoology Unit; Research Department Animal Sciences; Technische Universität München; Hans-Carl-von-Carlowitz-Platz 2 D-85354 Freising Germany
| | - Ralph Kühn
- Molecular Zoology Unit; Research Department Animal Sciences; Technische Universität München; Hans-Carl-von-Carlowitz-Platz 2 D-85354 Freising Germany
- Wildlife and Conservation Ecology and Molecular Biology Program; Department of Fish; New Mexico State University; Box 30003 MSC 4901 Las Cruces NM 88003-8003 USA
| | - Daniel W. Förster
- Department of Evolutionary Genetics; Leibniz-Institute for Zoo and Wildlife Research; Alfred-Kowalke-Str. 17 D-10315 Berlin Germany
| | - Jörns Fickel
- Department of Evolutionary Genetics; Leibniz-Institute for Zoo and Wildlife Research; Alfred-Kowalke-Str. 17 D-10315 Berlin Germany
| | - Christian Roos
- Gene Bank of Primates and Primate Genetics Laboratory; German Primate Center; Leibniz Institute for Primate Research; Kellnerweg 4 D-37077 Göttingen Germany
| | - Carsten Nowak
- Conservation Genetics Group; Senckenberg Research Institute and Natural History Museum Frankfurt; D-63571 Gelnhausen Germany
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17
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Mudunuri SB, Patnana S, Nagarajaram HA. MICdb3.0: a comprehensive resource of microsatellite repeats from prokaryotic genomes. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2014; 2014:bau005. [PMID: 24536078 PMCID: PMC3926409 DOI: 10.1093/database/bau005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The MICdb is a comprehensive relational database of perfect microsatellites extracted from completely sequenced and annotated genomes of bacteria and archaea. The current version MICdb3.0 is an updated and revised version of MICdb2.0. As compared with the previous version MICdb2.0, the current release is significantly improved in terms of much larger coverage of genomes, improved presentation of queried results, user-friendly administration module to manage Simple Sequence Repeat (SSR) data such as addition of new genomes, deletion of obsolete data, etc., and also removal of certain features deemed to be redundant. The new web-interface to the database called Microsatellite Analysis Server (MICAS) version 3.0 has been improved by the addition of powerful high-quality visualization tools to view the query results in the form of pie charts and bar graphs. All the query results and graphs can be exported in different formats so that the users can use them for further analysis. MICAS3.0 is also equipped with a unique genome comparison module using which users can do pair-wise comparison of genomes with regard to their microsatellite distribution. The advanced search module can be used to filter the repeats based on certain criteria such as filtering repeats of a particular motif/repeat size, extracting repeats of coding/non-coding regions, sort repeats, etc. The MICdb database has, therefore, been made portable to be administered by a person with the necessary administrative privileges. The MICdb3.0 database and analysis server can be accessed for free from www.cdfd.org.in/micas. Database URL:http://www.cdfd.org.in/micas
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Affiliation(s)
- Suresh B Mudunuri
- Department of Computer Science & Engineering, Grandhi Varalakshmi Venkatarao Institute of Technology, Bhimavaram, Andhra Pradesh 534 207, India, Training & Delivery Department, TalentSprint Educational Services, IIIT Campus, Hyderabad, Andhra Pradesh 500 032, India and Laboratory of Computational Biology, Centre for DNA Fingerprinting & Diagnostics, Hyderabad, Andhra Pradesh 500 001, India
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18
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Sun L, Zhang Q, Xu Z, Yang W, Guo Y, Lu J, Pan H, Cheng T, Cai M. Genome-wide DNA polymorphisms in two cultivars of mei (Prunus mume sieb. et zucc.). BMC Genet 2013; 14:98. [PMID: 24093913 PMCID: PMC3851432 DOI: 10.1186/1471-2156-14-98] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 09/25/2013] [Indexed: 11/10/2022] Open
Abstract
Background Mei (Prunus mume Sieb. et Zucc.) is a famous ornamental plant and fruit crop grown in East Asian countries. Limited genetic resources, especially molecular markers, have hindered the progress of mei breeding projects. Here, we performed low-depth whole-genome sequencing of Prunus mume ‘Fenban’ and Prunus mume ‘Kouzi Yudie’ to identify high-quality polymorphic markers between the two cultivars on a large scale. Results A total of 1464.1 Mb and 1422.1 Mb of ‘Fenban’ and ‘Kouzi Yudie’ sequencing data were uniquely mapped to the mei reference genome with about 6-fold coverage, respectively. We detected a large number of putative polymorphic markers from the 196.9 Mb of sequencing data shared by the two cultivars, which together contained 200,627 SNPs, 4,900 InDels, and 7,063 SSRs. Among these markers, 38,773 SNPs, 174 InDels, and 418 SSRs were distributed in the 22.4 Mb CDS region, and 63.0% of these marker-containing CDS sequences were assigned to GO terms. Subsequently, 670 selected SNPs were validated using an Agilent’s SureSelect solution phase hybridization assay. A subset of 599 SNPs was used to assess the genetic similarity of a panel of mei germplasm samples and a plum (P. salicina) cultivar, producing a set of informative diversity data. We also analyzed the frequency and distribution of detected InDels and SSRs in mei genome and validated their usefulness as DNA markers. These markers were successfully amplified in the cultivars and in their segregating progeny. Conclusions A large set of high-quality polymorphic SNPs, InDels, and SSRs were identified in parallel between ‘Fenban’ and ‘Kouzi Yudie’ using low-depth whole-genome sequencing. The study presents extensive data on these polymorphic markers, which can be useful for constructing high-resolution genetic maps, performing genome-wide association studies, and designing genomic selection strategies in mei.
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Affiliation(s)
- Lidan Sun
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, College of Landscape Architecture, Beijing Forestry University, 100083 Beijing, P,R, China.
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19
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Abstract
The ability to survey polymorphism on a genomic scale has enabled genome-wide scans for the targets of natural selection. Theory that connects patterns of genetic variation to evidence of natural selection most often assumes a diallelic locus and no recurrent mutation. Although these assumptions are suitable to selection that targets single nucleotide variants, fundamentally different types of mutation generate abundant polymorphism in genomes. Moreover, recent empirical results suggest that mutationally complex, multiallelic loci including microsatellites and copy number variants are sometimes targeted by natural selection. Given their abundance, the lack of inference methods tailored to the mutational peculiarities of these types of loci represents a notable gap in our ability to interrogate genomes for signatures of natural selection. Previous theoretical investigations of mutation-selection balance at multiallelic loci include assumptions that limit their application to inference from empirical data. Focusing on microsatellites, we assess the dynamics and population-level consequences of selection targeting mutationally complex variants. We develop general models of a multiallelic fitness surface, a realistic model of microsatellite mutation, and an efficient simulation algorithm. Using these tools, we explore mutation-selection-drift equilibrium at microsatellites and investigate the mutational history and selective regime of the microsatellite that causes Friedreich's ataxia. We characterize microsatellite selective events by their duration and cost, note similarities to sweeps from standing point variation, and conclude that it is premature to label microsatellites as ubiquitous agents of efficient adaptive change. Together, our models and simulation algorithm provide a powerful framework for statistical inference, which can be used to test the neutrality of microsatellites and other multiallelic variants.
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Affiliation(s)
- Ryan J Haasl
- Laboratory of Genetics, University of Wisconsin, USA.
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20
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Beal MA, Glenn TC, Lance SL, Somers CM. Characterization of unstable microsatellites in mice: no evidence for germline mutation induction following gamma-radiation exposure. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:599-607. [PMID: 22930577 DOI: 10.1002/em.21726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/19/2012] [Indexed: 06/01/2023]
Abstract
Large tandem repeat DNA loci such as expanded simple tandem repeats and minisatellites are efficient markers for detecting germline mutations; however, mutation detection using these loci can be imprecise and difficult to standardize across labs. Short-tandem repeats, such as microsatellites, offer more precise and high-throughput mutation detection, but germline mutation induction at these loci has not yet been studied in model organisms such as mice. In this study, we used microsatellite enrichment and large-scale DNA sequencing of several closely related inbred mouse lines to identify a panel of 19 polymorphic microsatellites with potentially high spontaneous mutation frequencies. We used this panel and four additional loci from other sources to quantify spontaneous mutation frequency in pedigrees of outbred Swiss-Webster mice. In addition, we also examined mutation induction in families in which sires were treated with acute doses of either 0.5 Gy or 1.0 Gy gamma-irradiation to spermatogonial stem cells. Per locus mutation frequencies ranged from 0 to 5.03 × 10(-3). Considering only the 11 loci with mutations, the mutation frequencies were: control 2.78 × 10(-3), 0.5 Gy 4.09 × 10(-3), and 1.0 Gy 1.82 × 10(-3). There were no statistically significant changes in mutation frequencies among treatment groups. Our study provides the first direct quantification of microsatellite mutation frequency in the mouse germline, but shows no evidence for mutation induction at pre-meiotic male germ cells following acute gamma-irradiation. Further work using the panel is needed to examine mutation induction at different doses of radiation, exposure durations, and stages during spermatogenesis.
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Affiliation(s)
- Marc A Beal
- Department of Biology, University of Regina, Regina, Saskatchewan, Canada S4S 0A2
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21
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Chapuis MP, Popple JAM, Berthier K, Simpson SJ, Deveson E, Spurgin P, Steinbauer MJ, Sword GA. Challenges to assessing connectivity between massive populations of the Australian plague locust. Proc Biol Sci 2011; 278:3152-60. [PMID: 21389030 PMCID: PMC3158929 DOI: 10.1098/rspb.2010.2605] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 02/15/2011] [Indexed: 11/12/2022] Open
Abstract
Linking demographic and genetic dispersal measures is of fundamental importance for movement ecology and evolution. However, such integration can be difficult, particularly for highly fecund species that are often the target of management decisions guided by an understanding of population movement. Here, we present an example of how the influence of large population sizes can preclude genetic approaches from assessing demographic population structuring, even at a continental scale. The Australian plague locust, Chortoicetes terminifera, is a significant pest, with populations on the eastern and western sides of Australia having been monitored and managed independently to date. We used microsatellites to assess genetic variation in 12 C. terminifera population samples separated by up to 3000 km. Traditional summary statistics indicated high levels of genetic diversity and a surprising lack of population structure across the entire range. An approximate Bayesian computation treatment indicated that levels of genetic diversity in C. terminifera corresponded to effective population sizes conservatively composed of tens of thousands to several million individuals. We used these estimates and computer simulations to estimate the minimum rate of dispersal, m, that could account for the observed range-wide genetic homogeneity. The rate of dispersal between both sides of the Australian continent could be several orders of magnitude lower than that typically considered as required for the demographic connectivity of populations.
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Affiliation(s)
- Marie-Pierre Chapuis
- School of Biological Sciences, University of Sydney, New South Wales 2006, Australia.
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22
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Genetic structure of farmer-managed varieties in clonally-propagated crops. Genetica 2011; 139:1055-64. [PMID: 21898046 DOI: 10.1007/s10709-011-9607-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
The relative role of sexual reproduction and mutation in shaping the diversity of clonally propagated crops is largely unknown. We analyzed the genetic diversity of yam-a vegetatively-propagated crop-to gain insight into how these two factors shape its diversity in relation with farmers' classifications. Using 15 microsatellite loci, we analyzed 485 samples of 10 different yam varieties. We identified 33 different genotypes organized in lineages supported by high bootstrap values. We computed the probability that these genotypes appeared by sexual reproduction or mutation within and between each lineage. This allowed us to interpret each lineage as a product of sexual reproduction that has evolved by mutation. Moreover, we clearly noted a similarity between the genetic structure and farmers' classifications. Each variety could thus be interpreted as being the product of sexual reproduction having evolved by mutation. This highly structured diversity of farmer-managed varieties has consequences for the preservation of yam diversity.
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23
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Hoffman JI, Grant SM, Forcada J, Phillips CD. Bayesian inference of a historical bottleneck in a heavily exploited marine mammal. Mol Ecol 2011; 20:3989-4008. [PMID: 21895820 DOI: 10.1111/j.1365-294x.2011.05248.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Emerging Bayesian analytical approaches offer increasingly sophisticated means of reconstructing historical population dynamics from genetic data, but have been little applied to scenarios involving demographic bottlenecks. Consequently, we analysed a large mitochondrial and microsatellite dataset from the Antarctic fur seal Arctocephalus gazella, a species subjected to one of the most extreme examples of uncontrolled exploitation in history when it was reduced to the brink of extinction by the sealing industry during the late eighteenth and nineteenth centuries. Classical bottleneck tests, which exploit the fact that rare alleles are rapidly lost during demographic reduction, yielded ambiguous results. In contrast, a strong signal of recent demographic decline was detected using both Bayesian skyline plots and Approximate Bayesian Computation, the latter also allowing derivation of posterior parameter estimates that were remarkably consistent with historical observations. This was achieved using only contemporary samples, further emphasizing the potential of Bayesian approaches to address important problems in conservation and evolutionary biology.
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Affiliation(s)
- J I Hoffman
- Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany.
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24
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Cavagnaro PF, Chung SM, Manin S, Yildiz M, Ali A, Alessandro MS, Iorizzo M, Senalik DA, Simon PW. Microsatellite isolation and marker development in carrot - genomic distribution, linkage mapping, genetic diversity analysis and marker transferability across Apiaceae. BMC Genomics 2011; 12:386. [PMID: 21806822 PMCID: PMC3162538 DOI: 10.1186/1471-2164-12-386] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 08/01/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Apiaceae family includes several vegetable and spice crop species among which carrot is the most economically important member, with ~21 million tons produced yearly worldwide. Despite its importance, molecular resources in this species are relatively underdeveloped. The availability of informative, polymorphic, and robust PCR-based markers, such as microsatellites (or SSRs), will facilitate genetics and breeding of carrot and other Apiaceae, including integration of linkage maps, tagging of phenotypic traits and assisting positional gene cloning. Thus, with the purpose of isolating carrot microsatellites, two different strategies were used; a hybridization-based library enrichment for SSRs, and bioinformatic mining of SSRs in BAC-end sequence and EST sequence databases. This work reports on the development of 300 carrot SSR markers and their characterization at various levels. RESULTS Evaluation of microsatellites isolated from both DNA sources in subsets of 7 carrot F2 mapping populations revealed that SSRs from the hybridization-based method were longer, had more repeat units and were more polymorphic than SSRs isolated by sequence search. Overall, 196 SSRs (65.1%) were polymorphic in at least one mapping population, and the percentage of polymophic SSRs across F2 populations ranged from 17.8 to 24.7. Polymorphic markers in one family were evaluated in the entire F2, allowing the genetic mapping of 55 SSRs (38 codominant) onto the carrot reference map. The SSR loci were distributed throughout all 9 carrot linkage groups (LGs), with 2 to 9 SSRs/LG. In addition, SSR evaluations in carrot-related taxa indicated that a significant fraction of the carrot SSRs transfer successfully across Apiaceae, with heterologous amplification success rate decreasing with the target-species evolutionary distance from carrot. SSR diversity evaluated in a collection of 65 D. carota accessions revealed a high level of polymorphism for these selected loci, with an average of 19 alleles/locus and 0.84 expected heterozygosity. CONCLUSIONS The addition of 55 SSRs to the carrot map, together with marker characterizations in six other mapping populations, will facilitate future comparative mapping studies and integration of carrot maps. The markers developed herein will be a valuable resource for assisting breeding, genetic, diversity, and genomic studies of carrot and other Apiaceae.
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Affiliation(s)
- Pablo F Cavagnaro
- Dept. of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA
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25
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Anmarkrud JA, Kleven O, Augustin J, Bentz KH, Blomqvist D, Fernie KJ, Magrath MJL, Pärn H, Quinn JS, Robertson RJ, Szép T, Tarof S, Wagner RH, Lifjeld JT. Factors affecting germline mutations in a hypervariable microsatellite: a comparative analysis of six species of swallows (Aves: Hirundinidae). Mutat Res 2011; 708:37-43. [PMID: 21291898 DOI: 10.1016/j.mrfmmm.2011.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/07/2011] [Accepted: 01/24/2011] [Indexed: 05/30/2023]
Abstract
Microsatellites mutate frequently by replication slippage. Empirical evidence shows that the probability of such slippage mutations may increase with the length of the repeat region as well as exposure to environmental mutagens, but the mutation rate can also differ between the male and female germline. It has been hypothesized that more intense sexual selection or sperm competition can also lead to elevated mutation rates, but the empirical evidence is inconclusive. Here, we analyzed the occurrence of germline slippage mutations in the hypervariable pentanucleotide microsatellite locus HrU10 across six species of swallow (Aves: Hirundinidae). These species exhibit marked differences in the length range of the microsatellite, as well as differences in the intensity of sperm competition. We found a strong effect of microsatellite length on the probability of mutation, but no residual effect of species or their level of sperm competition when the length effect was accounted for. Neither could we detect any difference in mutation rate between tree swallows (Tachycineta bicolor) breeding in Hamilton Harbour, Ontario, an industrial site with previous documentation of elevated mutation rates for minisatellite DNA, and a rural reference population. However, our cross-species analysis revealed two significant patterns of sex differences in HrU10 germline mutations: (1) mutations in longer alleles occurred typically in the male germline, those in shorter alleles in the female germline, and (2) male germline mutations were more often expansions than contractions, whereas no directional bias was evident in the female germline. These results indicate some fundamental differences in male and female gametogenesis affecting the probability of slippage mutations. Our study also reflects the value of a comparative, multi-species approach for locus-specific mutation analyses, through which a wider range of influential factors can be assessed than in single-species studies.
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Affiliation(s)
- Jarl A Anmarkrud
- National Centre for Biosystematics, Natural History Museum, University of Oslo, P.O. Box 1172 Blindern, NO-0318 Oslo, Norway.
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26
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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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27
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Nunes MDS, Wengel POT, Kreissl M, Schlötterer C. Multiple hybridization events between Drosophila simulans and Drosophila mauritiana are supported by mtDNA introgression. Mol Ecol 2010; 19:4695-707. [PMID: 20958812 PMCID: PMC3035818 DOI: 10.1111/j.1365-294x.2010.04838.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 06/17/2010] [Accepted: 06/19/2010] [Indexed: 11/30/2022]
Abstract
The study of speciation has advanced considerably in the last decades because of the increased application of molecular tools. In particular, the quantification of gene flow between recently diverged species could be addressed. Drosophila simulans and Drosophila mauritiana diverged, probably allopatrically, from a common ancestor approximately 250,000 years ago. However, these species share one mitochondrial DNA (mtDNA) haplotype indicative of a recent episode of introgression. To study the extent of gene flow between these species, we took advantage of a large sample of D. mauritiana and employed a range of different markers, i.e. nuclear and mitochondrial sequences, and microsatellites. This allowed us to detect two new mtDNA haplotypes (MAU3 and MAU4). These haplotypes diverged quite recently from haplotypes of the siII group present in cosmopolitan populations of D. simulans. The mean divergence time of the most diverged haplotype (MAU4) is approximately 127,000 years, which is more than 100,000 years before the assumed speciation time. Interestingly, we also found some evidence for gene flow at the nuclear level because an excess of putatively neutral loci shows significantly reduced differentiation between D. simulans and D. mauritiana. Our results suggest that these species are exchanging genes more frequently than previously thought.
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Affiliation(s)
- Maria D S Nunes
- Institut für Populationsgenetik, Veterinärmedizinische Universität Wien, Vienna, Austria
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28
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Cavagnaro PF, Senalik DA, Yang L, Simon PW, Harkins TT, Kodira CD, Huang S, Weng Y. Genome-wide characterization of simple sequence repeats in cucumber (Cucumis sativus L.). BMC Genomics 2010; 11:569. [PMID: 20950470 PMCID: PMC3091718 DOI: 10.1186/1471-2164-11-569] [Citation(s) in RCA: 258] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Accepted: 10/15/2010] [Indexed: 01/19/2023] Open
Abstract
Background Cucumber, Cucumis sativus L. is an important vegetable crop worldwide. Until very recently, cucumber genetic and genomic resources, especially molecular markers, have been very limited, impeding progress of cucumber breeding efforts. Microsatellites are short tandemly repeated DNA sequences, which are frequently favored as genetic markers due to their high level of polymorphism and codominant inheritance. Data from previously characterized genomes has shown that these repeats vary in frequency, motif sequence, and genomic location across taxa. During the last year, the genomes of two cucumber genotypes were sequenced including the Chinese fresh market type inbred line '9930' and the North American pickling type inbred line 'Gy14'. These sequences provide a powerful tool for developing markers in a large scale. In this study, we surveyed and characterized the distribution and frequency of perfect microsatellites in 203 Mbp assembled Gy14 DNA sequences, representing 55% of its nuclear genome, and in cucumber EST sequences. Similar analyses were performed in genomic and EST data from seven other plant species, and the results were compared with those of cucumber. Results A total of 112,073 perfect repeats were detected in the Gy14 cucumber genome sequence, accounting for 0.9% of the assembled Gy14 genome, with an overall density of 551.9 SSRs/Mbp. While tetranucleotides were the most frequent microsatellites in genomic DNA sequence, dinucleotide repeats, which had more repeat units than any other SSR type, had the highest cumulative sequence length. Coding regions (ESTs) of the cucumber genome had fewer microsatellites compared to its genomic sequence, with trinucleotides predominating in EST sequences. AAG was the most frequent repeat in cucumber ESTs. Overall, AT-rich motifs prevailed in both genomic and EST data. Compared to the other species examined, cucumber genomic sequence had the highest density of SSRs (although comparable to the density of poplar, grapevine and rice), and was richest in AT dinucleotides. Using an electronic PCR strategy, we investigated the polymorphism between 9930 and Gy14 at 1,006 SSR loci, and found unexpectedly high degree of polymorphism (48.3%) between the two genotypes. The level of polymorphism seems to be positively associated with the number of repeat units in the microsatellite. The in silico PCR results were validated empirically in 660 of the 1,006 SSR loci. In addition, primer sequences for more than 83,000 newly-discovered cucumber microsatellites, and their exact positions in the Gy14 genome assembly were made publicly available. Conclusions The cucumber genome is rich in microsatellites; AT and AAG are the most abundant repeat motifs in genomic and EST sequences of cucumber, respectively. Considering all the species investigated, some commonalities were noted, especially within the monocot and dicot groups, although the distribution of motifs and the frequency of certain repeats were characteristic of the species examined. The large number of SSR markers developed from this study should be a significant contribution to the cucurbit research community.
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Affiliation(s)
- Pablo F Cavagnaro
- Horticulture Department, University of Wisconsin, Madison, WI 53706, USA
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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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Ellison CK, Shaw KL. Mining non-model genomic libraries for microsatellites: BAC versus EST libraries and the generation of allelic richness. BMC Genomics 2010; 11:428. [PMID: 20624300 PMCID: PMC2996956 DOI: 10.1186/1471-2164-11-428] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 07/12/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Simple sequence repeats (SSRs) are tandemly repeated sequence motifs common in genomic nucleotide sequence that often harbor significant variation in repeat number. Frequently used as molecular markers, SSRs are increasingly identified via in silico approaches. Two common classes of genomic resources that can be mined are bacterial artificial chromosome (BAC) libraries and expressed sequence tag (EST) libraries. RESULTS 288 SSR loci were screened in the rapidly radiating Hawaiian swordtail cricket genus Laupala. SSRs were more densely distributed and contained longer repeat structures in BAC library-derived sequence than in EST library-derived sequence, although neither repeat density nor length was exceptionally elevated despite the relatively large genome size of Laupala. A non-random distribution favoring AT-rich SSRs was observed. Allelic diversity of SSRs was positively correlated with repeat length and was generally higher in AT-rich repeat motifs. CONCLUSION The first large-scale survey of Orthopteran SSR allelic diversity is presented. Selection contributes more strongly to the size and density distributions of SSR loci derived from EST library sequence than from BAC library sequence, although all SSRs likely are subject to similar physical and structural constraints, such as slippage of DNA replication machinery, that may generate increased allelic diversity in AT-rich sequence motifs. Although in silico approaches work well for SSR locus identification in both EST and BAC libraries, BAC library sequence and AT-rich repeat motifs are generally superior SSR development resources for most applications.
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Affiliation(s)
| | - Kerry L Shaw
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14850, USA
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Amos W. Heterozygosity and mutation rate: evidence for an interaction and its implications: the potential for meiotic gene conversions to influence both mutation rate and distribution. Bioessays 2010; 32:82-90. [PMID: 19967709 DOI: 10.1002/bies.200900108] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
If natural selection chose where new mutations occur it might well favour placing them near existing polymorphisms, thereby avoiding disruption of areas that work while adding novelty to regions where variation is tolerated or even beneficial. Such a system could operate if heterozygous sites are recognised and 'repaired' during the initial stages of crossing over. Such repairs involve an extra round of DNA replication, providing an opportunity for further mutations, thereby raising the local mutation rate. If so, the changes in heterozygosity that occur when populations grow or shrink could feed back to modulate both the rate and the distribution of mutations. Here, I review evidence from isozymes, microsatellites and single nucleotide polymorphisms that this potential is realised in real populations. I then consider the likely implications, focusing particularly on how these processes might affect microsatellites, concluding that heterozygosity does impact on the rate and distribution of mutations.
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Affiliation(s)
- William Amos
- Department of Zoology, University of Cambridge, UK.
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32
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Pemberton TJ, Sandefur CI, Jakobsson M, Rosenberg NA. Sequence determinants of human microsatellite variability. BMC Genomics 2009; 10:612. [PMID: 20015383 PMCID: PMC2806349 DOI: 10.1186/1471-2164-10-612] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 12/16/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Microsatellite loci are frequently used in genomic studies of DNA sequence repeats and in population studies of genetic variability. To investigate the effect of sequence properties of microsatellites on their level of variability we have analyzed genotypes at 627 microsatellite loci in 1,048 worldwide individuals from the HGDP-CEPH cell line panel together with the DNA sequences of these microsatellites in the human RefSeq database. RESULTS Calibrating PCR fragment lengths in individual genotypes by using the RefSeq sequence enabled us to infer repeat number in the HGDP-CEPH dataset and to calculate the mean number of repeats (as opposed to the mean PCR fragment length), under the assumption that differences in PCR fragment length reflect differences in the numbers of repeats in the embedded repeat sequences. We find the mean and maximum numbers of repeats across individuals to be positively correlated with heterozygosity. The size and composition of the repeat unit of a microsatellite are also important factors in predicting heterozygosity, with tetra-nucleotide repeat units high in G/C content leading to higher heterozygosity. Finally, we find that microsatellites containing more separate sets of repeated motifs generally have higher heterozygosity. CONCLUSIONS These results suggest that sequence properties of microsatellites have a significant impact in determining the features of human microsatellite variability.
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Affiliation(s)
- Trevor J Pemberton
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, USA.
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33
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34
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Haplotype-assisted characterization of germline mutations at short tandem repeat loci. Int J Legal Med 2009; 124:177-82. [DOI: 10.1007/s00414-009-0377-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 10/08/2009] [Indexed: 10/20/2022]
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35
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Amos W, Hoffman JI. Evidence that two main bottleneck events shaped modern human genetic diversity. Proc Biol Sci 2009; 277:131-7. [PMID: 19812086 DOI: 10.1098/rspb.2009.1473] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
There is a strong consensus that modern humans originated in Africa and moved out to colonize the world approximately 50 000 years ago. During the process of expansion, variability was lost, creating a linear gradient of decreasing diversity with increasing distance from Africa. However, the exact way in which this loss occurred remains somewhat unclear: did it involve one, a few or a continuous series of population bottlenecks? We addressed this by analysing a large published dataset of 783 microsatellite loci genotyped in 53 worldwide populations, using the program 'Bottleneck'. Immediately following a sharp population decline, rare alleles are lost faster than heterozygosity, creating a transient excess of heterozygosity relative to allele number, a feature that is used by Bottleneck to infer historical events. We find evidence of two primary events, one 'out of Africa' and one placed around the Bering Strait, where an ancient land bridge allowed passage into the Americas. These findings agree well with the regions of the world where the largest founder events might have been expected, but contrast with the apparently smooth gradient of variability that is revealed when current heterozygosity is plotted against distance from Africa.
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Affiliation(s)
- W Amos
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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36
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Marriage TN, Hudman S, Mort ME, Orive ME, Shaw RG, Kelly JK. Direct estimation of the mutation rate at dinucleotide microsatellite loci in Arabidopsis thaliana (Brassicaceae). Heredity (Edinb) 2009; 103:310-7. [PMID: 19513093 PMCID: PMC2749907 DOI: 10.1038/hdy.2009.67] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The mutation rate at 54 perfect (uninterrupted) dinucleotide microsatellite loci is estimated by direct genotyping of 96 Arabidopsis thaliana mutation accumulation lines. The estimated rate differs significantly among motif types with the highest rate for AT repeats (2.03 x 10(-3) per allele per generation), intermediate for CT (3.31 x 10(-4)), and lowest for CA (4.96 x 10(-5)). The average mutation rate per generation for this sample of loci is 8.87 x 10(-4) (s.e.=2.57 x 10(-4)). There is a strong effect of initial repeat number, particularly for AT repeats, with mutation rate increasing with the length of the microsatellite locus in the progenitor line. Controlling for motif and initial repeat number, chromosome 4 exhibited an elevated mutation rate relative to other chromosomes. The great majority of mutations were gains or losses of a single repeat. Generally, the data are consistent with the stepwise mutation model of microsatellite evolution. Several lines exhibited multiple step changes from the progenitor sequence, but it is unclear whether these are multi-step mutations or multiple single-step mutations. A survey of dinucleotide repeats across the entire Arabidopsis genome indicates that AT repeats are most abundant, followed by CT, and CA.
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Affiliation(s)
- Tara N. Marriage
- Department of Ecology and Evolutionary Biology University of Kansas, Lawrence, KS
| | - Stephen Hudman
- Department of Ecology and Evolutionary Biology University of Kansas, Lawrence, KS
- Department of Ecology, Evolution, and Behavior, University of Minnesota
| | - Mark E. Mort
- Department of Ecology and Evolutionary Biology University of Kansas, Lawrence, KS
| | - Maria E. Orive
- Department of Ecology and Evolutionary Biology University of Kansas, Lawrence, KS
| | - Ruth G. Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology University of Kansas, Lawrence, KS
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37
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Gordeeva NV, Sipko TP, Gruzdev AP. Microsatellite DNA variability in the populations of muskoxen Ovibos moschatus transplanted into the Russian North. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409070096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Rahim F. In silico comparison of simple sequence repeats in high nucleotides-rich genomes of microorganism. Pak J Biol Sci 2009; 11:2372-81. [PMID: 19137845 DOI: 10.3923/pjbs.2008.2372.2381] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study determined the distribution of a specific group of Simple Sequence Repeats (SSRs), in genome sequences of 7 chromosomes (Shigella flexneri 2a str 301 and 2457 T, Shigella sonnei, E. coli K12, M. tuberculosis, M. leprae and S. saprophytycus) have downloaded from the GenBank database for identifying abundance, distribution and composition of SSRs. The data obtained in the present study show that: (i) Tandem repeats are widely distributed throughout the genomes. (ii) SSRs are differentially distributed among coding and non-coding regions in investigated Shigella genomes. (iii) Total frequency of SSRs in non-coding regions is higher than coding regions. (iv) In all investigated chromosomes ratio of Tri-nucleotide SSRs are much higher than randomized genomes and Di nucleotide SSRs are lower. (v) Ratio of total and mono-nucleotide SSRs in real genome is higher than randomized genomes in E. coli K12, Sh. flexneri str 301 and S. saprophyticus, while it is lower in Sh. flexneri str 2457T, Sh. sonnei and M. tuberculosis and it is approximately same in M. leprae. (vi) Frequency of codon repetitions are vary considerably depending on the type of encoded amino acid.
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Affiliation(s)
- Fakher Rahim
- Physiology Research Center, Ahwaz Jondishpour University of Medical Sciences, Ahwaz, Iran
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39
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Evidence for Nonindependent Evolution of Adjacent Microsatellites in the Human Genome. J Mol Evol 2009; 68:160-70. [DOI: 10.1007/s00239-008-9192-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 12/02/2008] [Accepted: 12/02/2008] [Indexed: 10/21/2022]
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40
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Yin TM, Zhang XY, Gunter LE, Li SX, Wullschleger SD, Huang MR, Tuskan GA. Microsatellite primer resource for Populus developed from the mapped sequence scaffolds of the Nisqually-1 genome. THE NEW PHYTOLOGIST 2009; 181:498-503. [PMID: 19121044 DOI: 10.1111/j.1469-8137.2008.02663.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this study, 148 428 simple sequence repeat (SSR) primer pairs were designed from the unambiguously mapped sequence scaffolds of the Nisqually-1 genome. The physical position of the priming sites were identified along each of the 19 Populus chromosomes, and it was specified whether the priming sequences belong to intronic, intergenic, exonic or UTR regions. A subset of 150 SSR loci were amplified and a high amplification success rate (72%) was obtained in P. tremuloides, which belongs to a divergent subgenus of Populus relative to Nisqually-1. PCR reactions showed that the amplification success rate of exonic primer pairs was much higher than that of the intronic/intergenic primer pairs. Applying ANOVA and regression analyses to the flanking sequences of microsatellites, the repeat lengths, the GC contents of the repeats, the repeat motif numbers, the repeat motif length and the base composition of the repeat motif, it was determined that only the base composition of the repeat motif and the repeat motif length significantly affect the microsatellite variability in P. tremuloides samples. The SSR primer resource developed in this study provides a database for selecting highly transferable SSR markers with known physical position in the Populus genome and provides a comprehensive genetic tool to extend the genome sequence of Nisqually-1 to genetic studies in different Populus species.
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Affiliation(s)
- T M Yin
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - X Y Zhang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - L E Gunter
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - S X Li
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - S D Wullschleger
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - M R Huang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
| | - G A Tuskan
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA;The Key Lab of Forest Genetics and Gene Engineering, Nanjing Forestry University, Nanjing, China
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41
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Ortego J, Aparicio JM, Cordero PJ, Calabuig G. Characteristics of loci and individuals are associated with germline microsatellite mutation rates in lesser kestrels (Falco naumanni). Mutat Res 2008; 648:82-86. [PMID: 18973763 DOI: 10.1016/j.mrfmmm.2008.09.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 09/23/2008] [Accepted: 09/24/2008] [Indexed: 05/27/2023]
Abstract
Although microsatellites are one of the most popular tools in genetic studies, their mutational dynamics and evolution remain unclear. Here, we apply extensive pedigree genotyping to identify and analyze the patterns and factors associated with de novo germline mutations across nine microsatellite loci in a wild population of lesser kestrels (Falco naumanni). A total of 10 germline mutations events were unambiguously identified in four loci, yielding an average mutation rate of 2.96x10(-3). Across loci, mutation rate was positively correlated with locus variability and average allele size. Mutations were primarily compatible with a stepwise mutation model, although not exclusively involved single-step changes. Unexpectedly, we found an excess of maternally transmitted mutations (male-to-female ratio of 0.1). One of the analyzed loci (Fn2.14) resulted hypermutable (mutation rate=0.87%). This locus showed a size-dependent mutation bias, with longer alleles displaying deletions or additions of a small number of repeat than shorter alleles. Mutation probability at Fn2.14 was higher for females and increased with parental (maternal) age but was not associated with individual physical condition, multilocus heterozygosity, allele length or allele span. Overall, our results do not support the male-biased mutation rate described in other organisms and suggest that mutation dynamics at microsatellite loci are a complex process which requires further research.
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Affiliation(s)
- Joaquín Ortego
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.
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42
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ALLY D, RITLAND K, OTTO SP. Can clone size serve as a proxy for clone age?An exploration using microsatellite divergence inPopulus tremuloides. Mol Ecol 2008; 17:4897-911. [DOI: 10.1111/j.1365-294x.2008.03962.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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43
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Hosseini A, Ranade SH, Ghosh I, Khandekar P. Simple sequence repeats in different genome sequences of Shigella and comparison with high GC and AT-rich genomes. ACTA ACUST UNITED AC 2008; 19:167-76. [PMID: 18464038 DOI: 10.1080/10425170701461730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Simple sequence repeats (SSRs) are omnipresent in prokaryotes and eukaryotes, and are found anywhere in the genome in both protein encoding and noncoding regions. In present study the whole genome sequences of seven chromosomes (Shigella flexneri 2a str301 and 2457T, Shigella sonnei, Escherichia coli k12, Mycobacterium tuberculosis, Mycobacterium leprae and Staphylococcus saprophyticus) have downloaded from the GenBank database for identifying abundance, distribution and composition of SSRs and also to determine difference between the tandem repeats in real genome and randomness genome (using sequence shuffling tool) of the organisms included in this study. The data obtained in the present study show that: (i) tandem repeats are widely distributed throughout the genomes; (ii) SSRs are differentially distributed among coding and noncoding regions in investigated Shigella genomes; (iii) total frequency of SSRs in noncoding regions are higher than coding regions; (iv) in all investigated chromosomes ratio of Trinucleotide SSRs in real genomes are much higher than randomness genomes and Di nucleotide SSRs are lower; (v) Ratio of total and mononucleotide SSRs in real genome is higher than randomness genomes in E. coli K12, S. flexneri str 301 and S. saprophyticus, while it is lower in S. flexneri str 2457T, S.sonnei and M. tuberculosis and it is approximately same in M. leprae; (vi) frequency of codon repetitions are vary considerably depending on the type of encoded amino acids.
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Affiliation(s)
- Ashraf Hosseini
- Institute of Bioinformatics and Biotechnology, University of Pune, Pune, India.
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44
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Brandstrom M, Bagshaw AT, Gemmell NJ, Ellegren H. The Relationship Between Microsatellite Polymorphism and Recombination Hot Spots in the Human Genome. Mol Biol Evol 2008; 25:2579-87. [DOI: 10.1093/molbev/msn201] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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45
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The rate and spectrum of microsatellite mutation in Caenorhabditis elegans and Daphnia pulex. Genetics 2008; 178:2113-21. [PMID: 18430937 DOI: 10.1534/genetics.107.081927] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The effective use of microsatellite loci as tools for microevolutionary analysis requires knowledge of the factors influencing the rate and pattern of mutation, much of which is derived from indirect inference from population samples. Interspecific variation in microsatellite stability also provides a glimpse into aspects of phylogenetic constancy of mutational processes. Using long-term series of mutation-accumulation lines, we have obtained direct estimates of the spectrum of microsatellite mutations in two model systems: the nematode Caenorhabditis elegans and the microcrustacean Daphnia pulex. Although the scaling of the mutation rate with the number of tandem repeats is highly consistent across distantly related species, including yeast and human, the per-cell-division mutation rate appears to be elevated in multicellular species. Contrary to the expectations under the stepwise mutation model, most microsatellite mutations in C. elegans and D. pulex involve changes of multiple repeat units, with expansions being much more common than contractions.
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46
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Abstract
The mutation process ultimately defines the genetic features of all populations and, hence, has a bearing on a wide range of issues involving evolutionary genetics, inheritance, and genetic disorders, including the predisposition to cancer. Nevertheless, formidable technical barriers have constrained our understanding of the rate at which mutations arise and the molecular spectrum of their effects. Here, we report on the use of complete-genome sequencing in the characterization of spontaneously arising mutations in the yeast Saccharomyces cerevisiae. Our results confirm some findings previously obtained by indirect methods but also yield numerous unexpected findings, in particular a very high rate of point mutation and skewed distribution of base-substitution types in the mitochondrion, a very high rate of segmental duplication and deletion in the nuclear genome, and substantial deviations in the mutational profile among various model organisms.
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47
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Wanner RM, Güthlein C, Springer B, Böttger EC, Ackermann M. Stabilization of the genome of the mismatch repair deficient Mycobacterium tuberculosis by context-dependent codon choice. BMC Genomics 2008; 9:249. [PMID: 18507851 PMCID: PMC2430213 DOI: 10.1186/1471-2164-9-249] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 05/28/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The rate at which a stretch of DNA mutates is determined by the cellular systems for DNA replication and repair, and by the nucleotide sequence of the stretch itself. One sequence feature with a particularly strong influence on the mutation rate are nucleotide repeats. Some microbial pathogens use nucleotide repeats in their genome to stochastically vary phenotypic traits and thereby evade host defense. However, such unstable sequences also come at a cost, as mutations are often deleterious. Here, we analyzed how these opposing forces shaped genome stability in the human pathogen Mycobacterium tuberculosis. M. tuberculosis lacks a mismatch repair system, and this renders nucleotide repeats particularly unstable. RESULTS We found that proteins of M. tuberculosis are encoded by using codons in a context-dependent manner that prevents the emergence of nucleotide repeats. This context-dependent codon choice leads to a strong decrease in the estimated frame-shift mutation rate and thus to an increase in genome stability. CONCLUSION These results indicate that a context-specific codon choice can partially compensate for the lack of a mismatch repair system, and helps to maintain genome integrity in this pathogen.
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Affiliation(s)
- Roger M Wanner
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, CH-8006 Zürich, Switzerland.
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Microsatellite evolution: Mutations, sequence variation, and homoplasy in the hypervariable avian microsatellite locus HrU10. BMC Evol Biol 2008; 8:138. [PMID: 18471288 PMCID: PMC2396632 DOI: 10.1186/1471-2148-8-138] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 05/09/2008] [Indexed: 02/01/2023] Open
Abstract
Background Microsatellites are frequently used genetic markers in a wide range of applications, primarily due to their high length polymorphism levels that can easily be genotyped by fragment length analysis. However, the mode of microsatellite evolution is yet not fully understood, and the role of interrupting motifs for the stability of microsatellites remains to be explored in more detail. Here we present a sequence analysis of mutation events and a description of the structure of repeated regions in the hypervariable, pentanucleotide microsatellite locus HrU10 in barn swallows (Hirundo rustica) and tree swallows (Tachycineta bicolor). Results In a large-scale parentage analysis in barn swallows and tree swallows, broods were screened for mutations at the HrU10 locus. In 41 cases in the barn swallows and 15 cases in the tree swallows, mutations corresponding to the loss or gain of one or two repeat units were detected. The parent and mutant offspring alleles were sequenced for 33 of these instances (26 in barn swallows and 7 in tree swallows). Replication slippage was considered the most likely mutational process. We tested the hypothesis that HrU10, a microsatellite with a wide allele size range, has an increased probability of introductions of interruptive motifs (IMs) with increasing length of the repeated region. Indeed, the number and length of the IMs was strongly positively correlated with the total length of the microsatellite. However, there was no significant correlation with the length of the longest stretch of perfectly repeated units, indicating a threshold level for the maximum length of perfectly repeated pentanucleotide motifs in stable HrU10 alleles. The combination of sequence and pedigree data revealed that 15 barn swallow mutations (58%) produced alleles that were size homoplasic to other alleles in the data set. Conclusion Our results give further insights into the mode of microsatellite evolution, and support the assumption of increased slippage rate with increased microsatellite length and a stabilizing effect of interrupting motifs for microsatellite regions consisting of perfect repeats. In addition, the observed extent of size homoplasy may impose a general caution against using hypervariable microsatellites in genetic diversity measures when alleles are identified by fragment length analysis only.
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Merkel A, Gemmell NJ. Detecting microsatellites in genome data: variance in definitions and bioinformatic approaches cause systematic bias. Evol Bioinform Online 2008; 4:1-6. [PMID: 19204802 PMCID: PMC2614199 DOI: 10.4137/ebo.s420] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Microsatellites are currently one of the most commonly used genetic markers. The application of bioinformatic tools has become common practice in the study of these short tandem repeats (STR). However, in silico studies can suffer from study bias. Using a meta-analysis on microsatellite distribution in yeast we show that estimates of numbers of repeats reported by different studies can differ in the order of several magnitudes, even within a single genome. These differences arise because varying definitions of microsatellites, spanning repeat size, array length and array composition, are used in different search paradigms, with minimum array length being the main influencing factor. Structural differences in the implemented search algorithm additionally contribute to variation in the number of repeats detected. We suggest that for future studies a consistent approach to STR searches is adopted in order to improve the power of intra- and interspecific comparisons.
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Affiliation(s)
- Angelika Merkel
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
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McConnell R, Middlemist S, Scala C, Strassmann JE, Queller DC. An unusually low microsatellite mutation rate in Dictyostelium discoideum, an organism with unusually abundant microsatellites. Genetics 2007; 177:1499-507. [PMID: 17947436 PMCID: PMC2147952 DOI: 10.1534/genetics.107.076067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 09/04/2007] [Indexed: 01/13/2023] Open
Abstract
The genome of the social amoeba Dictyostelium discoideum is known to have a very high density of microsatellite repeats, including thousands of triplet microsatellite repeats in coding regions that apparently code for long runs of single amino acids. We used a mutation accumulation study to see if unusually high microsatellite mutation rates contribute to this pattern. There was a modest bias toward mutations that increase repeat number, but because upward mutations were smaller than downward ones, this did not lead to a net average increase in size. Longer microsatellites had higher mutation rates than shorter ones, but did not show greater directional bias. The most striking finding is that the overall mutation rate is the lowest reported for microsatellites: approximately 1 x 10(-6) for 10 dinucleotide loci and 6 x 10(-6) for 52 trinucleotide loci (which were longer). High microsatellite mutation rates therefore do not explain the high incidence of microsatellites. The causal relation may in fact be reversed, with low mutation rates evolving to protect against deleterious fitness effects of mutation at the numerous microsatellites.
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Affiliation(s)
- Ryan McConnell
- Department of Ecology and Evolutionary Biology, Rice University, Houston, Texas 77005, USA
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