Inter-Research
Diseases of Aquatic Organisms

ABSTRACT: The importance of tissue-specificity was studied in Myxobolus spp. infecting the gills of 7 cyprinid species. The 18S rDNA of 10 Myxobolus species was amplified by optimised nested-PCR, resulting in ~1600 bp PCR products. Phylogenetic trees generated by distance matrix and parsimony analyses revealed 4 main groups. Muscle-infecting species all belonged to the same group, while members of 2 gill-infecting groups were clearly distinguishable on the basis of tissue-specificity, and were also recognisable by differences in spore morphology. On the basis of tissue tropism, phylogenetic relationships among the species examined indicate that genetic separation is a more ancient evolutionary feature than host-specificity.

KEY WORDS: Myxobolus · Myxosporeans · Phylogeny · 18S rDNA · Tissue tropism · Cyprinids · Gills

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Published in DAO Vol. 58, No. 1 (2004) on January 28
Print ISSN: 0177-5103; Online ISSN: 1616-1580. Copyright © Inter-Research, Oldendorf/Luhe, 2004