Ecological and genetic differentiation of Daphnia galeata populations across Europe [Elektronische Ressource] / von Outi Helena Dove

Paco Und Outi

Informations

• Publié par: goethe_universitat_frankfurt_am_main
• Publié le: 01 janvier 2005
• Nombre de lectures: 17
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Ecological and genetic differentiation of
Daphnia galeata populations across Europe




Dissertation
zur Erlangung des Doktorgrades
der Naturwissenschaften



vorgelegt beim Fachbereich „Biowissenschaften“ (FB 15)
der Johann Wolfgang Goethe - Universität
in Frankfurt am Main





von
Outi Helena Dove
aus Bad Bentheim




Frankfurt 2005
2












vom Fachbereich „Biowissenschaften“ (FB 15) der Johann Wolfgang Goethe - Universität als
Dissertation angenommen.









Dekan: Prof. Dr. H. D. Osiewacz


Gutachter: Prof. Dr. B. Streit und Prof. Dr. J. Oehlmann

Datum der Disputation:. .11. November 2005.....................................................................

Contents 3
Contents
1. Introduction and outline of the thesis.............................................................. 6
1.1. General introduction..................................................................................... 6
1.2. Daphnia as a model organism....................................................................... 9
1.3. Population genetic structure and gene flow of a cyclic parthenogenetic
organism......................................................................................................... 10
1.3.1. Genetic variation within Daphnia populations................................ 11
1.3.2. Genetic differentiation among Daphnia populations...................... 11
1.4. The role of Daphnia in freshwater trophic cascades................................. 12
1.5. Outline of the thesis...................................................................................... 13
2. Clonal diversity and population structure of Daphnia galeata............. 15
2.1. Abstract......................................................................................................... 15
2.2. Introduction.................................................................................................. 15
2.3. Materials and methods................................................................................ 17
2.3.1. Sampling and identification of Daphnia galeata ............................ 17
2.3.2. Microsatellite amplification and genotyping.................................. 17
2.3.3. Genotypic diversity......................................................................... 19
2.3.4. Genetic differentiation among populations.................................... 20
2.4. Results.......................................................................................................... 20
2.4.1. Clonal diversity within Daphnia galeata populations.................... 21
2.4.2. Population structure and geographic patterns.............................. 25
2.5. Discussion.................................................................................................... 28
2.5.1. Clonal diversity.............................................................................. 28
2.5.2. Genetic variation within populations............................................. 29
2.5.3. Population structure and geographic patterns.............................. 31
2.6. Conclusion................................................................................................... 33
3. Current and historic genetic differentiation among European Daphnia
galeata populations............................................................................................. 34
3.1. Abstract....................................................................................................... 34
3.2. Introduction................................................................................................ 34
3.3. Materials and methods.............................................................................. 36
3.3.1. Sampling and identification of Daphnia galeata............................ 36
3.3.2. Genotyping and sequencing........................................................... 36
3.3.3. Data analysis................................................................................. 37
Contents 4
3.3.4. Gene flow analysis......................................................................... 39
3.4. Results......................................................................................................... 40
3.4.1. Estimates of genetic diversity........................................................ 40
3.4.2. Analysis of population structure.................................................... 42
3.4.3. Gene flow....................................................................................... 46
3.5. Discussion.................................................................................................... 48
3.5.1. Population genetic structure of Daphnia galeata based on
mitochondrial and microsatellite data.......................................... 49
3.5.2. Population history and genetic pattern of recolonization............ 50
3.6. Conclusion.................................................................................................. 53
4. Current and historic genetic differentiation among European
Daphnia galeata populations......................................................................... 54
4.1. Abstract....................................................................................................... 54
4.2. Introduction................................................................................................ 54
4.3. Materials and methods.............................................................................. 56
4.3.1. Study sites and sampling............................................................... 56
4.3.2 Determination of taxon richness and clonal diversity................... 57
4.3.3. Statistical analysis........................................................................ 58
4.4. Results........................................................................................................ 59
4.4.1. Environmental factors and interpopulation genetic differentiation 59
4.4.2. Environmental factors and intrapopulation genetic diversity...... 63
4.4.3. Partition of explained variation within and differentiation among
populations.................................................................................... 65
4.5. Discussion................................................................................................... 66
4.5.1. Variation within populations........................................................ 66
4.5.2. Variation among populations....................................................... 68
4.6. Conclusion.................................................................................................. 69
5. General discussion.............................................................................................. 70
5.1 Genetic structure within Daphnia galeata populations.......................... 70
5.2. Genetic structure among ........................ 72
5 .3. Concluding remarks................................................................................ 74
6. Zusammenfassung............................................................................................ 75
7. Aknowledgements............................................................................................. 82
8. References............................................................................................................ 84
Contents 5
Appendix................................................................................................................... 96
Curriculum vitae........................................................................................................ 98

1. Introduction 6
1. Introduction and outline of the thesis

1.1. General introduction

Studies on genetic structure in natural populations, including within and among population
genetic diversity and genetic differentiation, have been a major topic in evolutionary ecology
and genetics (Schmith 1998). This genetic architecture of a species depends on random
processes such as the initial founder effect, genetic drift (the unpredictable change in gene
frequency due to finite population size) and mutation and other non random events such as
gene flow (the change of gene frequency due to movements of gametes, e.g. via individuals
from one population to another), selection and reproduction mode (Avise 1994; Hartl and
Clark 1989). Mutation, genetic drift and natural selection favour adaptations to local
environmental conditions leading to the genetic differentiation of local populations, whereas
effective gene flow will oppose that differentiation (Slatkin 1987). Since local adaptation may
alter the genetic structure of a species, caused by natural selection, environmental
characteristics mediate population structure (Turner et al. 2001). Currently there is growing
interest in combining the tools of molecular genetics with the principles of ecological
biogeography and landscape ecology. Although