PALECOEVOL · Paleo-ecogenomics in Daphnia: developing a model for studying evolutionary impacts of climate and environmental change

Paleo-ecogenomics in Daphnia: developing a model for studying evolutionary impacts of climate and environmental change

Global climate change and anthropogenic pollution are among the most prominent forces that affect biodiversity. Numerous recent examples demonstrate microevolutionary changes in response to an increase in temperature and added indirect effects of anthropogenic stressors, magnifying the negative effects on biological systems. Temperature changes have been especially pronounced in the polar regions, with the Arctic warming faster than any other region on earth. In Greenland, air temperature has repeatedly gone through cycles of warm and cold periods over the past 2000 years. In order to study the response of organisms and their populations, historical datasets across centuries are especially useful to document genomic alterations related to such environmental changes. In this project, paleogenetic and paleogenomic methods were applied to reconstruct ancient populations and their individual genomes. The overarching goal of this project was to study the genomic responses of the ecological and genomic model organism Daphnia, a small aquatic crustacean that is central to aquatic foodwebs, to repeated shifts in temperature and related environmental parameters. A new method was refined for amplifying ancient DNA of eggs that lay dormant in the sediment of lakes. This DNA amplification is necessary to allow sequencing of the minute amount of DNA material present in these eggs. The successful amplification of DNA of 300 eggs collected from sediment (10 to 300 years old) was achieved, and the resulting genomic libraries are now being prepared for sequencing. In the next step, this will enable the association of genetic and genomic changes with detailed information on the environmental history on a long-term temporal scale to uncover genomic mechanisms and adaptation to rapidly changing environments. A preliminary population genetic analysis detected identical microsatellite genotypes across hundreds of years, and suggests genetic stability despite rapid environmental change.

Data: CORDIS, © European Union