Genome data represent the largest and most diverse set of heritable characters for comparative evolutionary studies. In collaboration with the The Wellcome Trust Sanger Institute, we have recently characterised and assembled the complete genome of Hymenolepis microstoma, a classical tapeworm model with over 50 years of literature supporting it.
Together with colleagues from the University of Würzburg, Germany, Peter Olson and Magdalena Zarowiecki have recently published the first insights into the gene content and general characteristics of tapeworm genomes based on data from Hymenolepis and the medically important genera Echinococcus and Taenia. Findings show that tapeworms have small genomes at ~150 Mb, compared to ~350 Mb in flukes and over 700 Mb in free-living planarians.
Their genomes are compact, containing few repetitive or mobile elements, and appear to contain a majority of common gene families, albeit they may be missing ~10% of 'core' or universal metazoan genes found in free-living animals and typically show a reduction in the number of genes per family. A number of necessary biosynthesis components are missing, such as genes required to synthesise cholesterol, and hence these essential molecules must be taken directly from the host. Data are now publicly available via the Web and promise to accelerate the pace of research in the field by eliminating the need for time consuming and costly genetic manipulations at the bench.
PD Olson, M Zarowiecki, F Kiss and K Brehm (2011). Invited review: Cestode genomics--progress and prospects for understanding basic and applied aspects of flatworm biology. Parasite Immunology [doi: 10.1111/j.1365-3024.2011.01319.x]