DOCSLIB.ORG

Genetic Erosion in Gradually and Go Unnoticed for a Long Time

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Genetic Erosion in Gradually and Go Unnoticed for a Long Time The term erosion is evocative of gradual loss of not catastrophic, are often balanced by mutation and something important that will eventually undermine gene flow, and typically do not occur in concert across the health or stability of dependent individuals or the entire species. Generally, loss of genetic diversity is a communities. As applied to genetic diversity, erosion is more serious threat to species that were formerly more the loss of genetic diversity within a species. It can widespread and have lost habitat and diversity recently happen fairly quickly — as with a catastrophic event than to species that are naturally restricted in their or change in land use that removes large numbers of occurrence. individuals and their habitat. But it can also occur more Influences that could contribute to genetic erosion in gradually and go unnoticed for a long time. Genetic native plant species include: major losses of habitat erosion can represent the loss of entire populations and the resident plant populations; fragmentation of genetically differentiated from others, the loss or change habitat; management activities such as thinning, in frequency of specific alleles (i.e., different forms of a harvesting, or nursery selections that target certain gene) within populations or over the species as a whole, features of plants; and planting material from a narrow or the loss of allele combinations. genetic collection in revegetation efforts. For example, in [ genetic erosion can result a restoration effort in southern California for eelgrass from habitat loss and (Zostera marina), genetic analyses revealed that the transplanted eelbeds had significantly lower genetic fragmentation and seed diversity than natural, undisturbed beds. collections that are Genetic erosion can be addressed at several levels in the too restricted ] spectrum of management activities. Other than the obvious measures of avoiding major losses or fragmen- Genetic diversity is important to a species’ fitness, tation of habitat (to the extent it disrupts natural gene long-term viability, and ability to adapt to changing flow between populations), the risk of genetic erosion environmental conditions (as explained in Volume 1). in native plant species can be minimized in specific Also, plant populations that are less genetically diverse revegetation projects by following these four guidelines: may be more susceptible, in some cases, to pathogens or other environmental stresses. Genetically eroded Collect seeds or other propagation materials populations may be less competitive with introduced (cuttings, for example) in such a manner invasive species. Overall, genetic erosion can have that representative genetic diversity of the cascading effects throughout the ecosystem. geographic area is conserved. Guidance for genet- Some loss of genetic diversity is expected under natural ically appropriate collections can be obtained from the conditions as a result of natural selection and genetic references provided in this volume. Such collections con- drift (see Volume 3). However, these losses are usually sider the geographic source or provenance, the number National Forest Genetics Laboratory (NFGEL) Genetic Resources Conservation Program Pacific Southwest Research Station University of California USDA Forest Service One Shields Avenue 2480 Carson Road Davis, CA USA 95616 Placerville, CA USA 95667 http://www.grcp.ucdavis.edu http://www.fs.fed.us/psw/programs/nfgel/ More Information Writing woody plant specifications for restoration and mitigation practices. (2000) S. Buis. Native Plants Journal 1:116-119. Genetic erosion, inbreeding, and reduced fitness in fragmented populations of the endangered tetraploid pea Swainsona recta. (2000) L. Buza, of parent plants, the number of seeds A. Young, and P. Thrall. Biological Conservation (or propagules) from each plant, and 93:177-186. their distance from one another. The Genetic sampling guidelines for conservation life-history features of a plant species collections of endangered plants. Center for will also help to guide appropriate Plant Conservation. (1991) In: D.A. Falk and K.E. genetic collections. For example, if the Holsinger (eds.). Genetics and conservation of rare plants. New York (NY): Oxford University species is dioecious, genetic collections Press. p 225-238. should reflect a balance of males and Genetic and demographic considerations in the females if collecting vegetative material sampling and reintroduction of rare plants. E.O. rather than seeds. If the plant species is Guerrant. (1992) In: P.L. Fiedler and S.K. Jain known to reproduce asexually, it is (eds.). Conservation biology: the theory and important to make collections from practice of nature conservation, preservation, various clones rather than within one and management. New York (NY): Routledge, or a few clones. Photo credits: (left two) Thomas D. “Tom” Landis, USDA Forest Service; (above) Chapman and Hall, Inc. p 321-344. James Denny Ward, USDA Forest Service. www.forestryimages.org. Loss of genetic diversity from managed popula- to release. The use of cultivars, per se, tions: interacting effects of drift, mutation, [ genetically eroded does not create genetic erosion. immigration, selection, and population subdivi- populations may be sion. (1987) R.C. Lacy. Conservation Biology However, if the cultivar is from a narrow 1:143-158. less competitive genetic base or has been genetically Population genetic analyses of transplanted eel- with introduced narrowed through nursery practices, grass (Zostera marina) beds reveal reduced and if it is used extensively to replace genetic diversity in southern California. (1996) invasive species ] original plant populations — or planted S.L. Williams and C.A. Davis. Restoration Ecology 4:163-180. in large numbers adjacent to plant Obtain geographic source infor- populations where interbreeding is likely Genetic erosion: No longer just an agricultural issue. (2004) D.L. Rogers. Native Plants Journal mation when purchasing plants to occur — this may contribute to 5:112-122. from a nursery. This information, as genetic erosion of the native plant Managing and monitoring genetic erosion. W.B. well as the collection methods and populations. Sherwin and C. Moritz. (2000) In: A.G. Young and conditions for growing out the plants, G.M. Clarke (eds.). Genetics, demography and will help you to determine whether Encourge and support nursery viability of fragmented populations. there is sufficient genetic diversity in management activities that aim Conservation Biology Series, Vol. 4 (Cambridge). the collection for your revegetation to maximize the proportion of p 9-34. project. By asking for this information, seeds that become healthy plantable seedlings. Good nursery The United States Department of Agriculture (USDA) it also helps to convey to the grower prohibits discrimination in all its programs and activities that this is an important part of the management — that is based on on the basis of race, color, national origin, gender, religion, awareness of possible genetic variation age, disability, political beliefs, sexual orientation and product’s value, and will provide marital or family status. (Not all prohibited bases apply to encouragement to collect and provide in seed characteristics, germination all programs.) Persons with disabilities who require alter- native means for communication of program informa- this information in the future. requirements, and growth patterns — tion (Braille, large print, audiotape, etc.) should contact includes measures to avoid inadvertent USDA’s TARGET Center at: (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write: USDA Use caution when planting culti- selection and minimize the impact on Director, Office of Civil Rights, Room 326-W, Whitten vars of native species. There is the genetic diversity of the original Building, 14th and Independent Avenue, SW, Washington, DC 20250-9410, or call: (202) 720-5964 (voice wide variation in genetic diversity in collection. (See Volume 10 for more or TDD). plants that are marketed as “cultivars” information.) USDA is an equal opportunity — depending on the original collection provider and employer. and the process it has experienced prior 2006.
Load more

Recommended publications
  • Chapter 4: Assessing the Threat of Genetic Erosion
    Chapter 4: Assessing the threat of genetic erosion P. Mathur Bioversity International Sub-Regional Office for South Asia ew Delhi, India E-mail: [email protected] Abstract The world community has confirmed its commitment to the conservation of plant genetic resources that provide valuable traits for meeting the challenges of the future, such as adapting crops to changing climatic conditions or disease outbreaks. However, this plant diversity is threatened by “genetic erosion”, a term coined by scientists for the loss of individual genes or combinations of genes, such as those found in locally adapted landraces. One of the main causes of genetic erosion is the replacement of local varieties by modern varieties. Other causes include environmental degradation, urbanization and land clearing through deforestation and bush fires. Genetic erosion can also occur on the level of germplasm collections and genebanks due to improper management and inadequate regeneration procedures. There is a need to strengthen the conservation and sustainable use of plants and seed systems, and the crucial linkages between them, through a combination of appropriate policies, use of scientific information, farmers’ knowledge, and action. Traditionally, efforts to counter genetic erosion have concentrated on conserving seeds in crop genebanks ( ex situ ). Today, it has become clear that the best strategy combines ex situ conservation with on-the-ground ( in situ ) conservation by farmers in their agro-ecosystems and of crop wild relatives in, for example, areas protected for their environmental value. While such mechanisms are vital, the sustainable use of plant genetic resources is likewise essential because plant genetic diversity increases options and provides insurance against future adverse conditions, such as extreme and variable environments.
    [Show full text]
  • Genetic and Demographic Dynamics of Small Populations of Silene Latifolia
    Heredity (2003) 90, 181–186 & 2003 Nature Publishing Group All rights reserved 0018-067X/03 $25.00 www.nature.com/hdy Genetic and demographic dynamics of small populations of Silene latifolia CM Richards, SN Emery and DE McCauley Department of Biological Sciences, Vanderbilt University, PO Box 1812, Station B, Nashville, TN 37235, USA Small local populations of Silene alba, a short-lived herbac- populations doubled in size between samples, while others eous plant, were sampled in 1994 and again in 1999. shrank by more than 75%. Similarly, expected heterozygosity Sampling included estimates of population size and genetic and allele number increased by more than two-fold in diversity, as measured at six polymorphic allozyme loci. individual populations and decreased by more than three- When averaged across populations, there was very little fold in others. When population-specific change in number change between samples (about three generations) in and change in measures of genetic diversity were considered population size, measures of within-population genetic together, significant positive correlations were found be- diversity such as number of alleles or expected hetero- tween the demographic and genetic variables. It is specu- zygosity, or in the apportionment of genetic diversity within lated that some populations were released from the and among populations as measured by Fst. However, demographic consequences of inbreeding depression by individual populations changed considerably, both in terms gene flow. of numbers of individuals and genetic composition. Some Heredity (2003) 90, 181–186. doi:10.1038/sj.hdy.6800214 Keywords: genetic diversity; demography; inbreeding depression; gene flow Introduction 1986; Lynch et al, 1995), the interaction of genetics and demography could also influence population persistence How genetics and demography interact to influence in common species, because it is generally accepted that population viability has been a long-standing question in even many abundant species are not uniformly distrib- conservation biology.
    [Show full text]
  • Crop Genetic Resources Bulletin Number 2 an Economic Appraisal May 2005 Kelly Day Rubenstein, Paul Heisey, Robbin Shoemaker, John Sullivan, and George Frisvold
    A Report from the Economic Research Service United States Department www.ers.usda.gov of Agriculture Economic Information Crop Genetic Resources Bulletin Number 2 An Economic Appraisal May 2005 Kelly Day Rubenstein, Paul Heisey, Robbin Shoemaker, John Sullivan, and George Frisvold Abstract: Crop genetic resources are the basis of agricultural production, and significant economic benefits have resulted from their conservation and use. However, crop genetic resources are largely public goods, so private incentives for genetic resource conservation may fall short of achieving public objectives. Within the U.S. germplasm system, certain crop collec- tions lack sufficient diversity to reduce vulnerability to pests and diseases. Many such genetic resources lie outside the United States. This report examines the role of genetic resources, genetic diversity, and efforts to value genetic resources. The report also evaluates economic and institutional fac- tors influencing the flow of genetic resources, including international agree- ments, and their significance for agricultural research and development in the United States. Keywords: Genetic resources, genetic diversity, germplasm, R&D, interna- tional transfer of genetic resources, in situ conservation, ex situ conserva- tion, gene banks, intellectual property. Acknowledgments: The authors wish to thank Allan Stoner, Henry Shands, and Peter Bretting for their thoughtful reviews and their valuable comments. Thanks for reviews above and beyond the call of duty belong to June Blalock, whose patience and insight were critical to the production of this report. We also thank Joe Cooper who reviewed portions of the manuscripts. Keith Wiebe provided helpful guidance in the development of the final draft. We thank Dale Simms for his excellent editorial work and Susan DeGeorge for her help with graphics and layout.
    [Show full text]
  • Contemporary Agriculture Vol
    Contemporary Agriculture Vol. 67, No. 1, Pp. 1 - 8, 2018. The Serbian Journal of Agricultural Sciences ISSN (Online) 2466-4774 UDC: 63(497.1)(051)-“540.2” www.contagri.info Review paper UDC: 582.542.11 DOI: 10.2478/contagri-2018-0001 AGROBIODIVERSITY GENETIC VARIABILITY UTILIZATION IN ORGANIC FOOD PRODUCTION* Miodrag DIMITRIJEVIĆ1♦, Sofija PETROVIĆ, Borislav BANJAC, Goran BARAĆ, Velimir MLADENOV1 Summary The food production at the global level is about to meet its border. Industrialization of agriculture correlates with an explosive enlargement of human population, during XX and at the beginning of XXI centuries. An ongoing process of environmental erosion has been speeding up during that period, not only in our physical surrounding, but also in biodiversity. A new direction in agricultural food production is in demand. Organic food production has been recognized as the way of providing safety and quality food, preserving the environment in the same time. In the other hand new land areas have to be explored for agricultural use, in order to enhance food quantity to meeting the increasing demand for food. These targets set new requirements in plant breeding. To fulfill these requirements the genetic variability harbored in genetic resources has to be preserved, examined and put to good use. Key words: biodiversity, organic, agriculture, genetics, breeding, agriculture INTRODUCTION The human population is growing in a burst. The World entered 20th Century with about 1.5 billion inhabitants, and left it enriched by more than 6 billion. In just 100 years the increment was three time bigger than in all previous human history. At the moment there is more than 7 billion of us, as UN reported, summarized by Roser and Ortiz- Ospina (2017).
    [Show full text]
  • Diversity on the Farm How Traditional Crops Around the World Help to Feed Us All, and Why We Should Reward the People Who Grow Them
    Diversity on the Farm How traditional crops around the world help to feed us all, and why we should reward the people who grow them. FORD FOUNDATION By Charles C. Mann POLITICAL ECONOMY RESEARCH INSTITUTE UNIVERSITY OF MASSACHUSETTS Maize Front cover, left: Hector Diaz Castellano, a Zapotec small-holder, on his farm in the hills of southern Mexico; right: an array of native maize varieties. Above and right: Post-harvest survey of native maize varieties at INIFAP, an agricultural-research institute outside the city of Oaxaca; inside left: making the maize drink atole in a country market; inside right: rinsing off the lime used to process maize kernels for hand-made tortillas in Ítanoni, an unusual gourmet tortillería in Oaxaca city that may serve as one model for saving agricultural biodiversity. By Charles C. Mann Photographs by Peter Menzel Diversity on the Farm Subhead if any goes here for the development of wild corn and Maize heirloom varieties At Ítanoni, hand-made tortillas 2 Mission Statements 17 From the Stomach 23 The Best Tortillas from single varieties of native maize to the Heart in Mexico are cooked on traditional circular 3 Foreword clay griddles called comales. 25 Notes 5 Introduction 19 What We Can Do: Five Approaches 28 Credits 7 Building the Roof with 1. LABELING Stones from the Foundation 2. CROP IMPROVEMENT 3. REMOVING PERVERSE INCENTIVES 11 Conserving Agricultural Biodiversity 4. PAYING FOR CURRENTLY Copyright 2004 UNCOMPENSATED SERVICES by the Ford Foundation all rights reserved. 13 A Community Effort 5. INCREASING SOCIAL CAPITAL Mission Statements FORD FOUNDATION The Ford Foundation is a resource for innovative people and institutions worldwide.
    [Show full text]
  • Genetic Erosion of Agrobiodiversity in India and Intellectual Property Rights: Interplay and Some Key Issues
    Genetic Erosion of Agrobiodiversity in India and Intellectual Property Rights: Interplay and some Key Issues Sabuj Kumar Chaudhuri [SRF (UGC) NET], Department of Library and Information Science, Jadavpur University, Kolkata-32 [West Bengal], India. email: [email protected] Abstract Agrobiodiversity is the backbone of a nation’s food security and the basis of economic development as a whole. Over the years this diversity in India is under pressure due to the massive commercialisation of agriculture leading to the almost extinction of traditional farming systems. The top-down system of agricultural research, where farmers are seen merely as recipients of research rather than as participants in it, has contributed to an increased dependence on a relatively few plant varieties. This trend and the increasing industrialization of agriculture are key factors in what can only be called "genetic erosion". The term refers to both the loss of species and the reduction of variety. Behind this commercialization there lies the interest of the breeders for obtaining intellectual property rights. It has a very complicated relationship with this diversity. The paper highlights this relationship and provides some suggestions in order to rectify the current negative phenomenon. India’s agrobiodiversity is most significant one in the world. This diversity is the result of thousand of years of farmer’s selection, experimentation (even cross breeding) and propagation of desirable traits of desirable species in innumerable ways for their subsistence and cultural purposes. Over the years this unparallel diversity of various crops of India has been eroded. Replacement of landraces (a crop cultivar that evolved with and has been genetically improved by traditional agriculturists, but has not been influenced by modern breeding practices) or TVs (traditional varieties) by MVs (modern varieties) or HYVs (High Yielding Varieties) is one of the most important reasons.
    [Show full text]
  • Training for Sustainable Food Systems Development Manual Training for Sustainable Food Systems Development Manual Table of Contents
    Training for sustainable food systems development Manual Training for sustainable food systems development Manual Table of contents General introduction 1 Training Unit 1: Healthy and sustainable diets 4 Unit 2: Biodiversity, seasonality and organic food 19 Unit 3: Water and land management food footprints 29 Unit 4: Food loss and food waste 40 Unit 5: Circular economy and resilience 48 Unit 6: Local economy and alternative systems 60 Unit 7: Ethic and inclusive food business models 71 Unit 8: Food and cultural heritage 82 Conclusion 90 Bibliography 91 Indice Introduction 1 Formazione Modulo 1: Diete sane e sostenibili 4 Modulo 2: Biodiversità, stagionalià ed alimenti biologici 19 Modulo 3: Impronte alimentari nella gestione dell’acqua e della terra 29 Modulo 4: Perdita e spreco di cibo 40 Modulo 5: Economia circolare e resilienza 48 Modulo 6: Economia locale e sistemi alternativi 60 Modulo 7: Modelli di business alimentari etici ed inclusivi 71 Modulo 8: Cibo e patrimonio culturale 82 Conclusioni 90 Bibliografia 91 Índice Introducción 1 Formación Unidad 1: Dietas sanas y sostenibles 4 Unidad 2: Biodiversidad, estacionalidad y comida orgánica 19 Unidad 3: Huellas alimentarias de la gestión del agua y de la tierra 29 Unidad 4: Pérdida y desperdicio de alimentos 40 Unidad 5: Economía circular y resiliencia 48 Unidad 6: Economía local y sistemas alternativos 60 Unidad 7: Modelos de negocio alimentarios éticos e inclusivos 71 Unidad 8: Comida y herencia cultural 82 Conclusión 90 Bibliografía 91 General introduction Food production, trade and consumption are the core of the relationship between humans and nature. Food is a key element of human's identity and cultural values.
    [Show full text]
  • Evolutionary History and Genetic Connectivity Across Highly Fragmented Populations of an Endangered Daisy
    Heredity (2021) 126:846–858 https://doi.org/10.1038/s41437-021-00413-0 ARTICLE Evolutionary history and genetic connectivity across highly fragmented populations of an endangered daisy 1 1 2 3 1 Yael S. Rodger ● Alexandra Pavlova ● Steve Sinclair ● Melinda Pickup ● Paul Sunnucks Received: 29 May 2020 / Revised: 24 January 2021 / Accepted: 25 January 2021 / Published online: 19 February 2021 © The Author(s) 2021. This article is published with open access Abstract Conservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate 1234567890();,: 1234567890();,: analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/ NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours.
    [Show full text]
  • Section A. Crop Wild Relatives A.1
    SECTION A. CROP WILD RELATIVES A.1. Introduction What are crop wild relatives? Crop wild relatives (CWR) are taxa closely related to crops and are defined by their potential ability to contribute beneficial traits for crop improvement; for example, to confer resistance to pests and diseases, improve tolerance to environmental conditions such as extreme temperatures, drought and flooding, and to improve nutrition, flavour, colour, texture and handling qualities . A working definition of a CWR based on the Gene Pool concept or, in the 1 absence of crossing and genetic diversity information, the Taxon Group concept , has been proposed: ‘‘A crop wild relative is a wild plant taxon that has an indirect use derived from its relatively close genetic relationship to a crop; this relationship is defined in terms of the CWR belonging to gene pools 1 or 2, or taxon groups 1 to 4 of the crop’’. Pyrus salicifolia Pall., a wild relative of pear (P. pyraster Burgsd.), in Naxcıvan, Azerbaijan. This species grows in very dry and rocky areas; in some places the seeds of P. salicifolia are used to obtain the rootstock for local varieties of pears (photo: Mirza Musayev). Genetic erosion is a key problem for CWR. What is genetic erosion? Genetic erosion is a fundamental problem for CWR and has been referred to in the literature as the permanent reduction in richness (total number of alleles) or evenness (i.e. spread of allelic diversity)3 of common local alleles, or the loss of combinations of alleles over time in a defined area4. Genetic erosion can affect wild populations conserved in situ and ex situ collections (i.e.
    [Show full text]
  • Challenges in Conserving and Utilizing Plant Genetic Resources (PGR)
    Vol. 6(2), pp. 16-22, March 2014 DOI: 10.5897/IJGMB2013.0083 Article Number: DE9B5EB47127 International Journal of Genetics and Molecular ISSN 2006-9863 Copyright © 2014 Biology Author(s) retain the copyright of this article http://www.academicjournals.org/IJGMB Review Challenges in conserving and utilizing plant genetic resources (PGR) Ogwu, M. C.*, Osawaru, M. E. and Ahana, C. M. Plant Conservation Unit, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Benin, Benin City, Edo State, Nigeria. Received 2 October, 2013; Accepted 22 January, 2014 The problems of food and income security are of global significance and are further compounded by precedential increase in world population resulting in overexploitation of natural resources and by extension plant genetic diversity. Plant genetic resources (PGR) refer to the heritable materials contained within and among plant species of present and potential value. In the recent past, genetic diversity found in landrace, weedy and wild cultivars have been reported to savage animal and plant population diseases, pest and environmental changes. Nevertheless, these resources are lost at alarming rates due to anthropogenic product and by products such as climate change, pollution, genetic erosion, gross mismanagement of these resources and population growth. Hence, the need for conservation and sustainable utilization of these resources. PGR conservation is the management of varietal diversity in plant occasioned by interaction between genes and the environment for actual or potential and present or future use. A complimentary application of in situ and ex situ conservation technique is recommended for their effective conservation. Efficient survey, collection and documentation is also pertinent.
    [Show full text]
  • Genetically Inherited Tolerance May Unveil Trait Dominance Patterns in an Amphibian Model E
    www.nature.com/scientificreports OPEN Genetically inherited tolerance may unveil trait dominance patterns in an amphibian model E. Fasola1,2*, R. Ribeiro2 & I. Lopes1 Chemical contamination may cause genetic erosion in natural populations by wiping out the most sensitive genotypes. This is of upmost concern if the loss of genetic variability is irreversible due to contaminant-driven elimination of alleles, which may happen if tolerance is a recessive or incompletely dominant trait – the recessive tolerance inheritance (working-) hypothesis. Accordingly, this work investigated the tolerance inheritance to lethal levels of a metal-rich acid mine drainage (AMD) and to copper sulphate in a population of Pelophylax perezi. Time-to-death for each egg, after being exposed to 60% of a sample of acid mine drainage and to 9 mg/L Cu, was registered, and, for each egg mass, the median lethal time (LT50) and respective quartiles (LT25 and LT75) were computed. Results suggested that genetically determined tolerance could be probably driven by incomplete dominance (with possible maternal efect infuence), preliminarily supporting the initial hypothesis. Understanding the tolerance of natural populations to stressors is important for conservation. Acting as a direc- tional selective pressure, a chemical stress can result in genetic erosion1, mainly if the within- (sensitive) genotype trait variability is low2,3. Researchers discussed if genetically determined tolerance stems from few major genes or from many minor genes (each giving a small contribution to the fnal phenotype). Both cases have been reported and were related with the intensity of the selective pressure4–6. Under mild contaminant concentrations, tolerance seems to have a polygenic basis, while under intense pollution pulses only few genes seem to play a central role5–7.
    [Show full text]
  • Monitoring Changes in Genetic Diversity
    Chapter 5 Monitoring Changes in Genetic Diversity Michael W. Bruford, Neil Davies, Mohammad Ehsan Dulloo, Daniel P. Faith and Michele Walters Abstract DNA is the most elemental level of biodiversity, drives the process of speciation, and underpins other levels of biodiversity, including functional traits, species and ecosystems. Until recently biodiversity indicators have largely over- looked data from the molecular tools that are available for measuring variation at the DNA level. More direct analysis of trends in genetic diversity are now feasible and are ready to be incorporated into biodiversity monitoring. This chapter explores the current state-of-the-art in genetic monitoring, with an emphasis on new molecular tools and the richness of data they provide to supplement existing approaches. We also briefly consider proxy approaches that may be useful for many-species, global scale monitoring cases. Keywords Biodiversity Á Molecular tools Á Genetic diversity Á Variation Á Monitoring M.W. Bruford (&) School of Biosciences and Sustainable Places Institute, Cardiff University, Cardiff, Wales CF10 3AX, UK e-mail: [email protected] N. Davies Richard P Gump South Pacific Research Station, University of California Berkeley, Moorea, French Polynesia e-mail: [email protected] M.E. Dulloo Biodiversity International, Maccarese, 00054 Fiumicino, Italy e-mail: [email protected] D.P. Faith The Australian Museum Research Institute, The Australian Museum, Sydney, Australia e-mail: [email protected] M. Walters Natural Resources and Environment, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, South Africa e-mail: [email protected] M. Walters Centre for Wildlife Management, University of Pretoria, Pretoria 0002, South Africa © The Author(s) 2017 107 M.
    [Show full text]