Molecular evolution of stress tolerance in wolf spiders (collaborative project with University of Gent, Belgium)
Background
Stress is a potent selective agent that drives adaptive evolution. We study the influence of heavy metal stress on population structure in soil ecosystems. Recently, we showed evidence that natural selection of heavy metal tolerance is achieved by evolution of transcriptional regulation in populations of the soil dwelling arthropod Orchesella cincta living in metal contaminated area’s. Stress response genes, highly inducible in sensitive refence populations, have evolved constitutively high transcriptional activity in heavy metal tolerant populations. Population genetic studies of wolf spider populations at metal contaminated sites have also indicated adaptive evolution of metal tolerance. However, it is currently unkown if stress-adaptive wolf spider phenotypes have evolved through differential transcriptional regulation of stress response genes, just like collembolans.
The aim of this study is to analyse transcriptional regulation of several genes that may potentially be involved in adaptation to heavy metal stress. We hypothesize that transcriptional regulation of stress response genes has been altered in the metal-tolerant wolf spider (Pardosa saltans) populations in such a way that these genes are constitutively over expressed.
Approach
This MSc internship will be a collaborative effort between th University of Gent and VU Animal Ecology. A pairwise sampling methods was performed in spring 2008. Wolf spiders were collected from 3 contaminated site together with 3 nearby clean reference site. A cDNA enrichment procedure was performed to isolate and sequence metal responsive genes. A large collection of animals is present in Gent and Amsterdam of exposed and non-exposed animals. RNA will be isolated and Realtime RT-PCR technology will be performed to quantify mRNA abundance of cadmium treated and non-treated animals for each population. Statistical analysis will be used to verify if Cd responsive genes show an interaction between treatment and population.
Dr. Ir. Dick Roelofs (Room H147, W&N building, Vrije Universiteit)
Email: dick.roelofs@falw.vu.nl
Ph: +31-20-5987078
