Perspectives on the ciliated protozoan Tetrahymena thermophila.

In biology, scientific discoveries are often linked to technical innovations made possible by an inspired choice of model organism. Ciliate species, especially Tetrahymena thermophila, have had historically significant roles as uniquely enabling experimental systems. More importantly, as the chapters in this volume attest, ongoing efforts of the T. thermophila model organism community have created a knowledge and resource infrastructure for systems-level studies across a whole genome or proteome, setting the stage for understanding the fundamental biology underlying the sophisticated life cycle and environmentally responsive behaviors of this free-living, single-celled eukaryote. One hope is that these developments will stimulate the integration of ciliates into phylogenomic comparative analyses and also encourage the experimental use of T. thermophila by a broader scientific community. This early branching yet highly gene-rich eukaryote has much to offer for future studies of human-relevant basic biology.