© 2007 The Authors Journal Compilation © 2007 Blackwell Publishing Ltd Geography Compass 1/3 (2007): 246–274, 10.1111/j.1749-8198.2007.00018.x Expanding Biogeographic Horizons with Genetic Approaches Kathleen Parker* and Scott Markwith University of Georgia Abstract The last decade has seen tremendous increases in the variety and cost-efficiency of markers available to investigate genetic questions. Molecular markers have been used in a number of biogeographic studies; however, most of this work has been done by scholars in fields other than geography, despite the inherently spatial nature of questions many authors have addressed. This article calls for greater contribution by geographers to this body of work. We begin with a primer that reviews several of the most commonly used molecular markers available today. Next, we illustrate the use of those markers with biogeographic studies in two areas that have a long-standing tradition within geography: paleoenvironmental reconstruction and human-biota interactions. Finally, we identify areas where genetic approaches can greatly expand our biogeographic horizons, including collaborative work with geographers in other subdisciplines, as well as with scholars in other fields. Introduction Since the mid-1990s, the forensic capabilities of DNA have captured the attention of the media and the public. DNA has been entered as evidence in sensational, as well as relatively mundane criminal trials; it has also established the identity or paternity of individuals, including identification of Nazi physician Josef Mengele, whose body was found buried under an alias in Brazil (Jeffreys et al. 1992). DNA has also been used to unravel mysteries pertaining to the realm of biogeography and evolutionary biology, such as determining the time of divergence of modern elephants from woolly mammoths based on ca.12,000-year-old DNA found in Siberia (Krause 2006), or identifying the diet of an iceman recently found in the Alps, based on the 5000-year-old frozen remains of his intestinal contents (Rollo et al. 2002). DNA sequencing (see Box 1 for a definition of basic genetic terms) and older genetic techniques have been used for several decades to address many biogeographic questions; however, the majority of this research has been done by scholars in other disciplines, with only minimal input from