Comparative genomics in the Amoebozoa clade.

Amoeboid life forms can be found throughout the evolutionary tree. The greatest proportion of these life forms is found in the Amoebozoa clade, one of the six major eukaryote evolutionary branches. Despite its common origin this clade exhibits a wide diversity of lifestyles including free-living and parasitic species and species with multicellular and multinucleate life stages. In this group, development, cooperation, and social behaviour can be studied in addition to traits common to unicellular organisms. To date, only a few Amoebozoa genomes have been sequenced completely, however a number of expressed sequence tags (ESTs) and complete and draft genomes have become available recently for several species that represent some of the major evolutionary lineages in this clade. This resource allows us to compare and analyse the evolutionary history and fate of branch-specific genes if properly exploited. Despite the large evolutionary time scale since the emergence of the major groups the genomic organization in Amoebozoa has retained common features. The number of Amoebozoa-specific genetic inventions seems to be rather small. The emergence of subgroups is accompanied by gene and domain losses and acquisitions of bacterial gene material. The sophisticated developmental cycles of Myxogastria and Dictyosteliida likely have a common origin and are deeply rooted in amoebozoan evolution. In this review we describe initial approaches to comparative genomics in Amoebozoa, summarize recent findings, and identify goals for further studies.