Welcome to my research page. I am currently a PhD student in evolutionary biology advised by Matthew Stephens and John Novembre. Evolutionary biology is concerned with studying how life came to be and it has been a personal obsession of mines. As you can imagine, it is a science encompassing many subfields and I specifically focus on studying population genetics. Population genetic models describe changes in genetic variation across time under evolutionary forces such as drift, selection, migration, and mutation. As you can tell from my header image, I am particularly fond of The Coalescent model. I think it’s a very exciting time to work in population genetics given the massive amounts of sequence data available. This is especially true for human sequence data, making humans a model system for studying population genetics. I am especially interested in combining population genetical theory with Bayesian statistics to study population structure across space and time.
Current Research Projects
1. Inferring recent population structure in humans
EEMS – Estimating Effective Migration Surfaces – is a recently developed method which sets out to estimate migration surfaces using a time homogenous stepping stone model. Although sometimes a good approximation, assuming constant migration rates throughout all time is not ideal for the human population. (As shown in the figure above, humans have been moving around quite a lot). In this project, I am developing a method to infer migration surfaces only in the recent past.
2. Spatial Analysis of Sardinia and the Mediterranean Region
Among other colleagues, I am involved in the population genetic analysis of the SardiNIA data. Specifically, I applied the EEMS method (mentioned above) to a merged data-set composed of thousands of individuals from the island of Sardinia and the Mediterranean region. Interestingly, I found a striking correspondence between the “effective migration surface” produced by EEMS and geography. For example, one can clearly see the Mediterranean sea emerge as a strong barrier; and for more fine scale structure, the mountainous regions of Sardinia.
(Photo Credit: Wikipedia)
3. Evaluating likelihood based dN/dS tests of positive selection
With Joe Thornton, I am evaluating the tests of positive selection in the package CODEML. We use both a combination of simulations and real data analysis. This research is in preparation for submission.
(Photo Credit: Roux et al MBE 2014)