This research will use computer mapping and DNA sequencing to study the geographic distributions (ranges) of a group of mammals and the evolutionary relationships among them. Spiny pocket mice originated in North America and later diversified to inhabit a remarkable array of environments in South America (from dry scrub, to rainforest, to wet forests in the mountains). The researchers will model the distribution of each species using climatic data for sites it is known to inhabit and determine the genealogical relationships among these species using DNA sequences. The results will answer questions regarding the group's diversification and colonization of South America, assess the species' current conservation status (using data from satellites showing remaining forested habitat), and predict their future ranges under scenarios of global climate change. Use of Geographic Information Systems (GIS; computer mapping programs) to model species distributions represents a new area of research with applications in areas as diverse as agriculture (distributions of pests), human health (distributions of disease vectors or reservoirs), and species conservation. This study will facilitate similar research on other species in the future. The researchers will train undergraduate and graduate students, including members from groups underrepresented in science.