Research Opportunities: Summer 2007 and 2007 - 2008 Academic Year

Population Genetics of Malaria Resistance in Humans: Malaria is one of the most significant ongoing health threats facing human populations. Despite this, populations in many parts of the globe harbor genetic variants that limit the severity of infection by malaria parasites. In Southeast Asia there exists a suite of molecular adaptations that confer resistance to malaria. Similar traits exist in other parts of the world (including the African hemoglobin variant underlying sickle-cell anemia, for example), but many of the specific polymorphisms found in SE Asia are unique and appear to be a convergent solution to the problem of malaria parasitism. My research seeks to understand how, when, and where these novel adaptations evolved.
    Currently, my research focuses on a variant known as Southeast Asian Ovalocytosis (SAO).  Individuals who are heterozygous for SAO have misshapen red blood cells due to a deletion in the gene encoding the membrane-bound Band 3 protein.  These individuals are also remarkably resistant to severe cerebral malaria.  Individuals who are homozygous for the Band 3 deletion appear to be inviable in utero, indicating a strong role for natural selection in the maintenance of the SAO allele. Ongoing work on this project seeks to characterize patterns of polymorphism at the Band 3 locus to better understand the form and strength of natural selection acting on the locus.

α-Amanitin Tolerance in Mycophagous Drosophila: α-amanitin is a powerful inhibitor of RNA polymerase II and is a common compound in many fungal species.  It is lethal to most eukaryotes (including humans) in very small doses.  Accordingly, mushrooms containing α-amanitin have common names that include the "destroying angel" and "green death cap".  Not surprisingly, these toxic mushrooms are consumed by very few organisms, with the exception of a number of Drosophila species that have apparently evolved complete tolerance to α-amanitin.  Research in my laboratory seeks to characterize the extent of natural α-amanitin tolerance among mycophagous Drosophila species, to determine the extent to which this trait can be selected for in laboratory experiments, and to identify the genetic basis of α-amanitin tolerant phenotypes. In addition to laboratory work this research has a major field component, as many α-amanitin tolerant species can be caught in the Williamstown area.

Speciation in the mosquito Anopheles gambiae: A. gambiae is the primary vector of malaria in sub-Saharan Africa. Interestingly, it appears to be undergoing a speciation event whereby it is splitting into two ecologically distinct species. By performing crosses in the laboratory, we will be invesigating whether there is any evidence for inviability of progeny that are the result of hybridization between these incipient species.


    Amanita phalloides - lethal to humans, a tasty treat for some Drosophila

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