PARENT SESSION

TRACING OF BOTTLENECK: COMPARATIVE PHYLOCHRONOLOGY OF C. SOCIABILIS AND C. HAIGI THOUGH 8000 YEARS. Yvonne L. Chan¹, Uma Ramakrishnan¹, Oliver P. Pearson² and Elizabeth A. Hadly¹. ¹ Department of Biological Sciences, Stanford University, Stanford, CA; ² (deceased) Museum of Vertebrate Zoology, Integrative Biology, University of California, Berkeley, CA.

ABSTRACT- Understanding the response of animal populations to climatic change is essential for the future maintenance of biodiversity. One question that remains difficult to answer, and is particularly important to conservation, is how animals respond over time scales relevant to evolutionary change. Ancient DNA provides a unique opportunity to track animal response to Holocene climate change and to study species replacement patterns and genetic diversity over time. We used ancient DNA to compare response to climatic change in two species, C. sociabilis and C. haigi, over the last 8,000 years. Our study site, Cueva Traful, is a late-Holocene raptor roost in Parque Nacional Nahuel Huapi, Argentina. A lack of genetic diversity in modern C. sociabilis populations is indicative of past bottleneck events and a previous ancient DNA study found that it had remained genetically identical for at least 1000 years in the face of climatic change and human disturbance. Since Cueva Traful goes back further in time, our first goal was to examine genetic diversity in order to place a longer term historical perspective on the modern bottleneck. The second goal was to compare changes in genetic diversity in C. sociabilis to C. haigi a closely related species that may respond differently to climatic change. The use of ancient DNA presents unique challenges due to low copy number, environmental damage to template, and high contamination risk. Despite these challenges, ancient DNA provides a unique perspective on evolutionary history.

KEY WORDS: Ctenomys haigi, Ctenomys sociabilis, ancient DNA, response to climatic change