Abstracts (first author)

Talk 

Rapid evolution of metal tolerance revealed by resurrecting dormant propagules

Author(s): Spaak P, Turko P

Summary:

We investigated the evolutionary response of an ecologically important freshwater crustacean, Daphnia, to a rapidly changing toxin environment. From the 1920s until the 1960s, the use of leaded gasoline caused the aquatic concentration of this toxin to increase at least 5-fold, presumably exerting rapid selective pressure on aquatic organisms to develop resistance. Similarly, we predicted that the banning of leaded gasoline, and the corresponding return to low lead levels, would result in the loss of resistance if this resistance carried a cost. These questions were addressed directly by using the resurrection ecology approach, whereby dormant propagules from a focal time period are hatched or germinated and compared to those from another time period. We hatched several Daphnia genotypes from each of two Swiss lakes, during times of higher (1960s / 1980s) and lower (2000s) lead stress, and compared their life histories under different laboratory levels of this stressor. The results were clear: modern Daphnia genotypes (hatched from a period of low lead pollution) had significantly reduced fitness, measured as the population growth rate (r), when exposed to lead, while those genotypes hatched from times of high lead pollution did not display this reduction. We conclude that Daphnia in these lakes were able to rapidly adapt to increasing lead concentrations, and just as rapidly lost this adaptation when the stressor was removed. These results are analyzed in context of the recent theoretical advances by Ellner et al. (2011), who developed a framework for the explicit comparison of ecological and evolutionary rates, and are used to demonstrate a previously unrecognized feature of their model. We also discuss avenues of further research into the genetic underpinnings of this adaptation, taking into account recent research on ABC transporters and technological advances in sequencing technology.



Abstracts (coauthor)

Unlocking poor quality Daphnia samples by SNP genotyping

Author(s): Rusek, J, Tellenbach C, Ayan G, Theodosiou L, Turko P, Giessler S, Spaak P, Wolinska J

Summary:

In order to track temporal-evolutionary changes in the plakton communities, as an important issue remains the proper identification of species and their hybrids. For the analyses of Daphnia longispina complex, microsatellie genotyping is a commonly used method. However, we found these length-based markers unsuitable when analyzing poor quality samples. Therefore the historical, formaldehyde preserved samples remain inaccessible. To overcome this problem, we propose SNP based genotyping, due to possibility of shorter fragment amplification. Furthermore, this method allows not only high-throughput genotyping, but the calibration among laboratories is also relatively precise. Therefore, we aim to develop a reliable method to identify species of the D. longispina complex and their hybrids by SNP genotyping. By comparing the transcriptome of D. galeata with D. pulex genome (wfleabase.org) we are identifying genes and their chromosomal location in order to obtain multi-loci markers, and corresponding primers are then being designed. After the sequencing and alignment of these genes for each species in the complex (D. cucullata, D. galeata and D. longispina), candidate SNPs are being identified. For the small scale confirmation of the diagnostic value of these candidate SNPs, we are sequencing a set of genetically well-defined clones from species and hybrids originating from diverse locations across Europe. For the large-scale screenings we are optimizing multiplex PCR reaction of short amplicons and SNP detection via SnaPshot Multiplex kit. To validate the results, we are applying the developed assay for the samples, which were previously analyzed with microsatellite markers. By multi-locus SNP genotyping we will be able to assess the population structures in long-term formaldehyde preserved samples of a hybridizing species complex.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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