Ancient insights into the effects of glacial cycles on Arctic marine mammal genetic diversity and distribution

Tara Fulton, Penn State

December 5, 2011 @ 03:00 pm to 04:00 pm

105 Forest Resources Building

The Arctic is warming at a rapid pace and arctic marine mammals with a high reliance on sea ice such as polar bears and walruses are some of the species most susceptible to climate warming. Understanding how these species have responded to past periods of climate warming, such as following the Last Glacial Maximum (LGM) ~20,000 years ago or during the previous interglacial ~125,000 years ago may help to predict population level responses to future and ongoing environmental change. _Ancient DNA can provide a window into these responses, tracking how populations change in genetic diversity and geographic distribution across these climatic events._ I will present recent collaborative work (Edwards et al. 2011, Curr.Biol.) using ancient DNA to investigate the role of glacial cycles in shaping the genetic history of polar bears, including the discovery of a major hybridization event between brown and polar bears that most likely occurred during the LGM. I will also discuss my ongoing work studying walruses from across the past 150,000 years and from across their circumarctic distribution. Preliminary results suggest that the genetic history of walruses has been repeatedly shaped by glacial events. I will present hypotheses about how both warm and cool periods contributed to shaping the present diversity and geographic range and the genomic approach I am currently undertaking to tackle how walrus populations respond to large-scale environmental change.

Contact

Jason Hill
ecologyservice@psu.edu