The origins and evolution of genes and organelles in eukaryotes

Living organisms can be classified into two kinds: those made up of cells with their genome encapsulated in a nucleus (eukaryotes, e.g. animals, fungi and plants), a cytoskeleton and an internal membrane systems with membranous organelles and cells lacking all of these characteristics (prokaryotes, e.g. bacteria). The origin of eukaryote cells from a consortium of symbiotic ancestors was the most profound, but poorly understood, transition in the evolutionary history of life. In this proposal we are attempting to understand how eukaryotic cells evolved by tracing the ancestry of the genes in the genomes of a variety of possibly primitive single-celled eukaryotes (protists, some human parasites) living in low oxygen habitats. We aim to determine the nature and numbers of prokaryotic partners that were involved in the origin of eukaryotes and their genomes and how often genes have been exchanged between prokaryotes and eukaryotes over the evolutionary history of life. Understanding the mechanisms by which the genomes and cells of microbial eukaryotes and prokaryotes have evolved will shed light on how parasitic forms arise and adapt to anti-microbial agents.