HOST-LIKE SEQUENCES IN THE SCHISTOSOME GENOME

A series of recent papers has indicated that widespread genomic rearra ngements take place in the genome of schistosomes during the life cycl e of the parasite. These results have been controversial since genomic rearrangements are not common in eukaryotes, probably because excessi ve genome plasticity would carry a heavy evolutionary price. Here, Kar en Clough, Alec Drew and Paul Brindley present data that ostensibly su pport the concept of widespread genomic rearrangements, but for which they suggest a different interpretation. They conclude that artefactua l contamination of schistosome genome preparations with host DNA can p robably explain the Southern hybridization results which led to the or iginal hypothesis of developmental, genomic rearrangements.