My main area of research is applied population genetics. I focus on understanding how migration and population structure influence the geographic distribution of genetic variation. I am particularly interested in tests of current methods used to infer human population history as well as developing new methods. 

Current Research

Evaluating Approximate Bayesian Computation. An exciting recent methodological advance in population genetics is approximate Bayesian computation (ABC; Beaumont et al. 2002). This approach exploits the computational efficiency of summary statistics in an approximation of the Bayesian statistical paradigm. After an exploratory application of this method in which I attempted to estimate the time of expansion of modern humans out of Africa, it became clear to me that research needed to be done to better understand the appropriate selection of summary statistics. To that end, I have been testing a wide array of statistics under simple models of population size changes. The goal is to increase the efficiency of ABC and have greater confidence in results from this method under a variety of population models.

Population History in the Horn of Africa and Middle East. Dr. Connie Mulligan (University of Florida) initiated an NSF funded research project to test the hypothesis that anatomically modern humans dispersed out of Africa through the “Southern” Horn of Africa to Arabia route rather than the “Northern” Levant route. I was brought into the Mulligan Lab as a postdoc on this project. With our colleague, Dr. Ali Al-Meri of Sana’a University, we collected saliva and blood samples in Yemen in Spring 2007 and have been analyzing these samples along with comparative sample collections from the Horn of Africa and the Arabian peninsula. I am continuing to work with Dr. Mulligan and Dr. Al-Meri on this project; we are particularly interested in developing multi-locus methods (data from mtDNA, the Y chromosome, and autosomes) to infer population history and the impact of cultural practices on genetic variation.

Projects in Development

Selection, Draft, and Human Allele Frequency Structure.
Unravelling Complex Population History in the Indian Ocean Basin.

Past Research

Nucelotide Substitution Rate Variation in Catarrhine Primates.
Molecular Phylogenetics of African Guenon Monkeys.