Understanding how—and how fast—organisms can respond to environmental change is key for predicting their resilience in facing global climate change. This is especially true in the Arctic, which is experiencing the most pronounced warming. Svalbard, an isolated, High-Arctic archipelago and the fastest warming site on Earth, is home to an endemic subspecies of wild reindeer that is uniquely adapted to its extreme Arctic home. Following colonization of Svalbard millennia ago, the population evolved several adaptations to this harsh and highly stochastic environment, including thick fur, a small body, a highly specialized diet, and altered metabolism.
This project seeks to directly assess how these isolated animals were able to adapt to a harsh and highly stochastic environment. To accomplish this, we will apply powerful evolutionary simulations and implement cutting-edge approaches to analyze hundreds of whole-genome sequences from modern reindeer populations from polar regions, including Svalbard. We will use this information to investigate how long-term changes in population size and dispersal reflect changes in the environment, such as gain or loss of sea ice corridors. Then, using genome sequences derived from ancient reindeer bones and antlers collected from the archipelago, we’ll look directly back in time through the history of Svalbard reindeer evolution, identifying the genetic changes that enabled the reindeer’s rapid evolution, and tracking these changes in time and space.
2022-12-18. Update. The project website has been established (www.coldrein.org), the first postdoc has been hired since 01.07.22. All the sequencing of the modern genomes for the project has been completed. A large field campaign to collect approximately 300 new bone/antler materials from Svalbard has been completed, and the work to genetically screening and radiocarbon-date these materials is underway. A paper reporting some first results regarding the genomic diversity of modern Svalbard reindeer has been submitted for publication.
Understanding the mechanisms and speed with which organisms respond to environmental change is key for predicting their resilience to global climate change. This is especially true in the Arctic, which accounts for 20% of Earth’s land surface and is experiencing the most pronounced warming. Svalbard, an isolated, High Arctic archipelago and the fastest warming site on Earth, is home to a genetically distinct, endemic subspecies of wild reindeer that is uniquely adapted to its extreme Arctic home. Following colonization of Svalbard within the past 6000 years, the population rapidly evolved myriad adaptive traits for a harsh and highly stochastic environment, including thick fur, a small body, a highly specialized diet, and altered metabolism, circadian rhythmicity, and behavior. Taking advantage of this unique natural experiment and abundant, readily available samples, ColdRein will directly assess how, and how quickly, an isolated animal population can adapt. To do this, we will generate a large circumpolar population genomic dataset, including an extinct subspecies from Greenland, and then apply powerful model-based simulations and genomic scanning methods that are at the very cutting edge of evolutionary genomics. We will integrate environmental and genomic data to determine how long-term fluctuations in effective population size and inter-population dispersal reflect climate and sea-ice dynamics. We will search the Svalbard reindeer genome for signatures of positive selection, and then for key adaptive alleles, will use CRISPR technology in a mouse model to directly link genotype with phenotype. Then we will reconstruct the genome sequences of ancient individuals, looking back in time through Svalbard reindeer evolution to track the origin of adaptive alleles and the subsequent timeline of their rise in frequency. In doing, so ColdRein will generate fundamental insights into the timeline for environmental adaptation at the subspecies level in a large mammal.