Clonal Diversity and Sex Ratio of a Malaria Parasite

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

Malaria parasites (Plasmodium) have a complex life cycle that consists of asexual reproduction (cell division) within the blood cells of vertebrate hosts (including humans and many wildlife species), and sexual reproduction within a blood-feeding insect. The parasites produce male and female sex cells (gametocytes) in blood cells, and these mate within the insect. Although the life cycle of the malaria parasite has been known for a century, one feature remains a mystery: why gametocyte sex ratio varies among Plasmodium species and even among infections for any one species. This study will be the first to study the molecular genetics of a natural malaria system to test sex ratio theory, a mainstay of evolutionary biology. It will examine how the genetic diversity of the parasite influences the ratio of male and female gametocytes (sex ratio), with experiments using a Plasmodium that infects a reptile host. The experiments will test the hypothesis that the sex ratio of those gametocytes is determined by how often matings occur between gametocytes that are genetically identical. The experiments will also test the hypothesis that the parasites are able to monitor the presence of kin and non-kin within a single infected individual. Malaria kills millions of people every year and is an important disease of many wild animals. The genetic diversity of parasites is thought to play a major role in their biology, including transmission and virulence, so the results of this study may provide important information for treating this disease. In addition, this project will result in the training of at least 10 undergraduate and graduate students.