A COMPARATIVE-STUDY OF WILLAERTIA-MAGNA (FREE-LIVING AMEBA) FROM DIFFERENT GEOGRAPHIC AREAS USING WHOLE-CELL AND SMALL-SUBUNIT RDNA RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMS

Nine strains of the free-living amoeba Willaertia magna and one of Nae gleria fowlen were compared by detection of whole-cell and small subun it ribosomal DNA (ssurDNA) restriction fragment length polymorphisms ( RFLPs). Ail strains of W. magna showed identical Pst I whole-cell RFLP s, although variation in Bg1 II, Hae III and Kpn I RFLPs were found. T hese RFLPs did not: correlate with the geographic origin of the strain s. Phylogenetic analysis of the whole-cell RFLPs separated the W. magn a strains into three distinct clusters. However, these were not suffic iently diverse to indicate interspecies-variation. Homologous ssurDNA RFLPs were found for ail strains of W. magna regardless of the restric tion endonuclease used. Both the whole-cell and ssurDNA RFLPs were dif ferent for W. magna and N. fowleri and can be used to identify the spe cies. On the basis of homologous whole-cell Pst I and ssurDNA RFLPS, t he findings of this study confirm that W. magna is a single species ge nus.