Organismal Diversity and Evolution
Studying the diversity and evolution of all organisms contributes to our understanding of the natural world and the forces that shape all life around us. This research has enabled IGS scientists to identify unique features or phenomena in pathogens that can be targeted with drugs, thus improving human health.
IGS scientists are examining a variety of animals and their associated microbial communities. These include familiar animals, such as humans and mice, but also small invertebrates including fruit flies, mosquitoes, ticks, mites and copepods (tiny aquatic crustaceans). Maladies associated with these complex interactions include cholera, West Nile virus, malaria, Lyme disease, ehrlichiosis, scabies, and even allergies. Scientists also focus on bacterial symbionts that are not pathogens but live intimately with an animal host, including the ubiquitous Wolbachia endosymbiont of arthopods and nematodes, as well as a Rickettisa endosymbiont of ticks. Wolbachia is so intimate with its hosts that copies of its genome can be found within the host genome.
Some of the most difficult diseases to treat are caused by eukaryotic pathogens. Eukaryotes are organisms whose cells - like ours, but unlike those of bacteria - include a nucleus and other complex structures within their cell membranes. Their similarities to us, both at the cellular and genomic levels. make many of the drugs that target these pathogens toxic to the human body. In addition, these organisms evolve resistance to drugs relatively rapidly. IGS scientists research several eukaryotic Apicomplexan pathogens, including the parasites that cause malaria, which kills a million people a year and infects half a billion; cryptosporidiosis ("crypto"), a diarrheal disease that can be fatal to children and people with weak immune systems like those with AIDS; and East Coast Fever, which kills a million cattle a year in eastern Africa. The group is using various techniques to try to understand what genes make the parasites pathogenic or allow them to survive in their hosts.
In order to understand what makes both bacterial and eukaryotic species unique, we need to uncover the traits that differentiate them, and characterize the functional implication of those differences. Several of the projects currently ongoing at IGS aim at identifying the genomic characteristics responsible for phenotypic differences between closely related species and strains, such as the variability in pathogenic properties between strains of the same species.
