Jumbled Genomes: Missing Apicomplexan Synteny

Mol Biol Evol. 2011 Apr 19. [Epub ahead of print]

Jumbled Genomes: Missing Apicomplexan Synteny

Debarry JD, Kissinger JC.
SourceCenter for Tropical and Emerging Global Diseases.

Abstract
Whole-genome comparisons provide insight into genome evolution by informing on gene repertoires, gene gains/losses and genome organization. Most of our knowledge about eukaryotic genome evolution is derived from studies of multi-cellular model organisms. The eukaryotic phylum Apicomplexa contains obligate intracellular protist parasites responsible for a wide range of human and veterinary diseases (e.g. malaria, toxoplasmosis, and theileriosis). We have developed an in silico protein-encoding gene based pipeline to investigate synteny across 12 apicomplexan species from 6 genera. Genome rearrangement between lineages is extensive. Syntenic regions (conserved gene content and order) are rare between lineages and appear to be totally absent across the phylum, with no group of three genes found on the same chromosome and in the same order within 25 kb up- and downstream of any orthologous genes. Conserved synteny between major lineages is limited to small regions in Plasmodium and Theileria/Babesia species and within these conserved regions there are a number of proteins putatively targeted to organelles. The observed overall lack of synteny is surprising considering the divergence times and the apparent absence of transposable elements (TEs) within any of the species examined. TEs are ubiquitous in all other groups of eukaryotes studied to date, and have been shown to be involved in genomic rearrangements. It appears that there are different criteria governing genome evolution within the Apicomplexa relative to other well-studied unicellular and multi-cellular eukaryotes.

PMID:21504890[PubMed - as supplied by publisher]