Abstract
We will study genetic changes over time in response to human impact by using diatom resting stages which continuously sediment to the bottom of the sea. From two eutrophicated fjords, with well-documented hydrographic history, we will collect sediment cores and establish S. marinoi populations spanning the age from 0-120 years old. We have recently sequenced the complete genome and we will use this as a back-bone for our analyses. We will resequence individuals from recent, 20, 40 and 120 year old sediments. Outlier analyses will tell us how big proportion of the genome that is under selection. The populations will be phenotyped, and individual fitness in response to pre-industrial and ambient nutrient conditions will be determined. From the resequenced genomes possible candidate genes with a high degree of polymorphism between the old and the young strains will be identified and PCR primers constructed. The candidate genes will be sequenced for hundreds of individuals from the old and young populations. With this approach we will likely find variation in specific genes that are strongly correlated with phenotypic trait values, and in this way infer links between genotype and phenotype. This research is important for increasing the scope of ecological risk assessment to include the effects of evolutionary response, for defining a genetic baseline for human-induced eutrophication, and for identifying markers which can be used to detect diffuse signals of eutrophication.
Sweden