title: Population genetic dynamics of an invasion reconstructed from the sediment egg bank.
abstract: Biological invasions are a global issue with far-reaching consequences for single species, communities and whole ecosystems. Our understanding of modes and mechanisms of biological invasions requires knowledge of the genetic processes associated with successful invasions. In many instances, this information is particularly difficult to obtain as the initial phases of the invasion process often pass unnoticed and we rely on inferences from contemporary population genetic data. Here, we combined historic information with the genetic analysis of resting eggs to reconstruct the invasion of Daphnia pulicaria into Lower Lake Constance (LLC) in the 1970s from the resting egg bank in the sediments. We identified the invader as 'European D. pulicaria' originating from meso- and eutrophic lowland lakes and ponds in Central Europe. The founding population was characterized by extremely low genetic variation in the resting egg bank that increased considerably over time. Furthermore, strong evidence for selfing and/or biparental inbreeding was found during the initial phase of the invasion, followed by a drop of selfing rate to low levels in subsequent decades. Moreover, the increase in genetic variation was most pronounced during early stages of the invasion, suggesting additional introductions during this period. Our study highlights that genetic data covering the entire invasion process from its beginning can be crucial to accurately reconstruct the invasion history of a species. We show that propagule banks can preserve such information enabling the study of population genetic dynamics and sources of genetic variation in successful invasive populations.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.|Institute of Integrative Biology, ETH Zurich, CH-8092, Zurich, Switzerland.|Department of Zoology, University of Cambridge, CB2 3EJ, Cambridge, UK.
authors.forename: Markus
authors.initials: M
authors.lastname: Möst
authors.affiliation: Limnological Institute, University of Konstanz, D-78464, Konstanz, Germany.|Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, B-3000, Leuven, Belgium.
authors.forename: Sarah
authors.initials: S
authors.lastname: Oexle
authors.affiliation: Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Rumburská 89, 27721, Liběchov, Czech Republic.
authors.forename: Silvia
authors.initials: S
authors.lastname: Marková
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
authors.forename: Dalia
authors.initials: D
authors.lastname: Aidukaite
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
authors.forename: Livia
authors.initials: L
authors.lastname: Baumgartner
authors.affiliation: Institute for Lake Research, D-88085, Langenargen, Germany.
authors.forename: Hans-Bernd
authors.initials: HB
authors.lastname: Stich
authors.affiliation: Institute for Lake Research, D-88085, Langenargen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wessels
authors.affiliation: Limnological Institute, University of Konstanz, D-78464, Konstanz, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Martin-Creuzburg
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.|Institute of Integrative Biology, ETH Zurich, CH-8092, Zurich, Switzerland.
authors.forename: Piet
authors.initials: P
authors.lastname: Spaak
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D003621:Daphnia / Q000235:genetics*; D005787:Gene Frequency; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D019015:Geologic Sediments; D005858:Germany; D007178:Inbreeding; D058865:Introduced Species; D060106:Lakes; D018895:Microsatellite Repeats; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010063:Ovum; D010802:Phylogeny; D011157:Population Dynamics; D017422:Sequence Analysis, DNA; D013557:Switzerland
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers
keywords: Daphnia; ancient DNA; asexual; egg bank; genetic variation; invasion