Regional genetic variation in the major sperm protein genes of Onchocerca volvulus and Mansonella ozzardi (Nematoda : Filarioidea)

Onchocerca volvulus and Mansonella ozzardi are two human filarial parasites present in South and Central America. In the Brazilian Amazonia they are f ound in sympatry, and the lack of clear morphological diagnostic characters in the microfilariae hinders their identification. The major sperm protein (MSP) gene of both species has been sequenced and characterised to determi ne its potential as a molecular diagnostic character. The length of the MSP gene is different in each species, and this could be used to detect and di fferentiate them by running the polymerase chain reaction (PCR) product in an agarose gel. Two major gene groups were identified in O. volvulus with a genetic distance of 6% between them. In M. ozzardi only one major group of genes was observed. The high similarity between the protein amino acid seq uence of both filarial species confirms that the MSP has been highly conser ved through nematode evolution. (C) 2000 Australian Society for Parasitolog y Inc. Published by Elsevier Science Ltd. All rights reserved.