Worpackage III

The adaptive phenotypic and genetic plasticity of endogenous rhythms in krill 

Carl von Ossietzky University Oldenburg(UO), University of Padova (UP), Alfred Wegener Institute for Polar and Marine Research (AWI)

The Gerlach lab at the University of Oldenburg will contribute to this project with its expertise in population genetics, quantitative genetics and statistical evaluations of population structure. The capability to cope with environmental changes can be regarded generally as a mechanism of adaptive phenotypic plasticity, or it might be based on genetic adaptation. The selective advantage of genetically based adaptations or maintained plasticity depends on the stability of environmental conditions; rapid shifts in living conditions might favour the later. Krill populations can be found at different latitudes in Polar Regions. The fate of krill will depend on its resilience to cope with changing environmental conditions, for instance day light. We aim at studying how strongly the endogenous rhythm is determined by phenotypic plasticity or limited by genetically based local adaptation. We will use the transcriptome (RNA) information obtained by the Costa and Meyer labs to find SNPs (single nucleotide polymorphisms) and microsatellite markers that are linked to clock genes (=non-neutral SNPs) and genes linked to the immune system and stress related genes such as Hsp70, Hsp90, hemocyanin, α2-Macroglobulins or arginine kinase which has been shown to change expression pattern in relation to stress in other crustaceans. We will compare those to EST-linked microsatellites that are apparently neutral [24]. We will determine genetic isolation of different krill populations from different zones with neutral and non-neutral genetic markers. Information from both analyses, will allow for a statistical calculation if clock-, stress – or immune related markers are under selection (comparison QST and FST). For each selected marker gene expression will be analysed using quantitative real time PCR (see below) whether they show differences between different light treatments of krill maintained in the Tasmanian laboratories. Our results will help to understand whether local populations can adapt to changed climate conditions, how genetic diversity influences their adaptation and finally on a long term, whether specifically adapted populations are likely to survive.

24. Bortolotto E, Bucklin A, Mezzavilla M, Zane L, Patarnello T (2011) Gone with the currents: lack of genetic differentiation at the circum-continental scale in the Antarctic krill Euphausia superba. BMC Genetics 12: doi: 10.1186/1471-2156-12-32