Impact of historical climate change on the genetic structure of the Great Basin Pocket Mouse, Perognathus parvus

The dynamics of genetic patterns, such as genetic differentiation within and between populations and the geographic distribution of genetic lineages, are often influenced by historical events (such as climatic changes) that have substantially impacted regional biodiversity (the study of phylogeography; Avise, 20001). The magnitude of genetic differentiation among populations is often increased if suitable habitat is reduced, because there is restricted migration among populations. When migration is restricted, the populations may become genetically differentiated from conspecific populations and, over time, may become independent lineages that follow distinctive evolutionary trajectories (Stebbins, 19523; Nevo & Beiles, 19892; Thomas et al., 19984). In particular, glacial cycles often result in expansion and contraction of suitable habitat for organisms, which we might predict leads to a similar expansion and contraction of organismal populations. Understanding the impact of past glacial-interglacial cycles (Figure 1), and thus climate changes, on species and species assemblages can help us understand what we may expect from current and future climate change trends