Population Genetics

Our research focuses on understanding how genetic variation is generated and maintained in natural populations. By identifying genes contributing to adaptive phenotypic variation, we can use population and ecological genetics to gain insight into the evolutionary process.

 

For example, we use population genetics to:

(1) estimate the age of adaptive alleles

(2) to estimate the strength of selection using patterns of nucleotide variation

(3) predict the order in which alleles were selected

(4) detemine if adaptive alleles were derived from standing genetic variation or new mutations.

 

We also use an ecological genetic approach by studying the spatial and temporal distribution of alleles. Thus, in addition to genetic crosses done in the laboratory, we study natural populations in the field. We have complementary projects focusing on:

(1) ecological genetics of clinal variation in pigmentation and skeletal morphology using museum skins collected in the 1920's

(2) population genetics and phylogeography of Peromyscus polionotus populations in the southwestern U.S.

(3) conservation genetics of endangered beach mouse subspecies.

 

Field work

Our lab takes advantage of phenotypic variation in natural populations of Peromyscus. Our lab has several field sites including in Florida, Nebraska, Bulgaria, South Carolina and New Mexico. We have recently begun collaborative work with researchers in Brazil. By examining populations occupying similar environments in diverse locales, we can ask if similar or different genetic mechanisms underlie convergent phenotypes.

Natural history collections

Hoekstra and MiceNatural history museums are repositories of morphological and distributional information. Museum specimens of Peromyscus polionotus date back to the late 1800's, but the most extensive collections belong to Francis Sumner from his surveys of Peromyscus populations in the 1920's. His classic studies on intraspecific variation laid the groundwork for our own research.

 

Museum specimens provide us with phenotypic data from known locations. In addition, we are able to extract DNA from these specimens using ancient DNA techniques. Thus, we can take advantage of hundreds of specimens from extant species as well as species that have gone extinct in historical time. These collections also allow us to incorporate a temporal component to our research, enabling us to document changes in both genetic and phenotypic variation over time.

 

We are part of the Museum of Comparative Zoology (MCZ) at Harvard University. Our collections are accessioned in the Mammal Department and are available to researchers throughout the world. The MCZ Mammal Collection is one of the largest historic, geographic, and taxonomically diverse university systematic collections in the world.