Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): The evolutionary ancestry of the eukaryotic shikimate pathway. The arom and other enzymes (colored ovals; see the key in the related article) have a complex evolutionary history, including fusion events, vertical transmission (grey lines), endosymbiotic gene replacements (multiple arrowheads/green lines), and separate horizontal gene transfers (single arrows). Enzyme localization infers ancestry, not functional localization. Eukaryotic organelles (M, mitochondria; P, plastid; A, apicoplastid; N, nucleus) and schematic cilia structures are shown. (See related article on page 1517.)

[Table of Contents]