Lab:
253F PSN

Biographical Information:

The Hoffman lab studies the evolutionary genetics of mammals; we are interested in the relationship between genetic diversity and population viability, especially as it relates to mammal conservation. We are analyzing the levels of genetic diversity in endangered versus expanding populations, taking advantage of recent dramatic shifts in the distributions of small mammals in the Great Lakes region. As an apparent response to climate change, some small mammals from the central Midwest are expanding northwards at an astonishing rate, and replacing more northern congeneric species. We are interested in how the interactions between closely related species in this region affect demographic and evolutionary processes such as inbreeding, real and effective population size, and population viability.

In collaboration with other laboratories, we have linked the overall pattern of small mammal movements in the region to warmer overwinter temperatures, but we still do not understand the proximate mechanisms by which one species replaces the other. We are currently focusing on the population genetics of woodland mice in Michigan, where a northern subspecies of deer mouse (Peromyscus maniculatus gracilis) is being replaced by the more southern white-footed mouse (Peromyscus leucopus noveboracensis). We have traced the history of P. maniculatus in the region, showing that populations on the Lower Peninsula of Michigan are descended from populations on the Upper Peninsula, but are now genetically separate and distinct. We are interested in using the patterns we have observed in these model species to frame questions about other small terrestrial animals in the region, some of which are of conservation concern.

In addition, we do a limited amount of research on the origins of genetic diversity in mammalian genomes by analyzing the organization and evolution of gene families. One cluster of genes from the cytochrome P450 gene superfamily has been studied in different mammal species, including human, mouse, rat, cat and gorilla. Comparisons of the same gene cluster in diverse species allow us to recreate the molecular processes, including tandem duplication and gene conversion events, which generate genetic diversity.