The Gile Lab

What are Protists?

Microbial eukaryotes, as protists are sometimes called, can be found in all kinds of habitats on Earth. They can be primary producers (algae), grazers (eating bacteria), predators (eating other protists), or live on or within multicellular hosts as mutualists, commensals, or parasites. The very first eukaryotes were protists, and all of the multicellular lineages (e.g., animals, plants, fungi) have evolved from protist lineages. Many, or perhaps most, protists are associated with symbiotic bacteria that provide fixed nitrogen or fixed carbon or some other metabolic benefit. Symbiosis has played a pivotal role in eukaryotic evolution by providing us with mitochondria and plants with chloroplasts. The Gile lab studies protist diversity and evolution from both morphological and molecular and perspectives, including microbiomics, comparative genomics, and phylogenetics. We are currently working on protists from hot springs, marine plankton, and the hindguts of wood-feeding termites.

PLASTID EVOLUTION

One of the most ancient and important symbioses of all is the establishment of plastids. Beginning over 1 billion years ago, when a host cell failed to digest its cyanobacterial food, an association between two single celled organisms gradually became a new, single organism. In the Gile lab we study the gene transfer and protein targeting that enabled the transition from symbiosis to new organism. We also study the loss of photosynthesis, which has happened many times in various lineages without loss of the plastid itself. Despite the importance of photosynthesis to life on earth, we do not fully understand how many times endosymbiosis has led to a new photosynthetic eukaryotic lineage, yet another topic of research in the Gile lab.

TERMITE PROTIST DIVERSITY

A major research focus in the Gile lab is the fascinating symbiosis occurs between termites and the protists that live in their hindguts. The termites rely on these protists to help them digest wood, and in return, the protists have a safe microcosm where they have flourished, evolving to become larger and morphologically more complex over about 150 million years of coevolution. Because most termite species have not yet had their hindgut communities investigated, the vast majority of symbiotic protist species are still unknown to science. We apply microscopy and molecular and computational techniques to study these protists, with particular interests in phylogeny, morphological convergence, genome evolution, and coevolution with their hosts.