RAPD in the analysis of isolates of Entamoeba histolytica

Genetic variability in Entamoeba histolytica was analyzed by random amplifi ed polymorphic DNA (RAPD) using ten arbitrary primers. Due to intrinsic cha racteristics of the RAPD technique only axenic samples were analyzed, since the presence of any microorganism in the cultures interfered in the DNA pr ofile by generating RAPDs not pertaining to E. histolytica. The RAPD profil es of E. histolytica samples isolated from patients with different clinical manifestations from different regions of the Americas shared about 70% of the bands produced. These profiles were compared to those obtained for E. m oshkovskii, and E. invadens. The combined data for the ten primers were use d in the phenetic analysis of all the isolates studied by using the Dice si milarity coefficient as the genetic distance measure between the samples. T hree distinct groups could be separated by phenon line: one including E. mo shkovskii samples, which shared > 90% of the RAPDs produced by the differen t primers: one consisting solely of E. invadens; and a third comprising sam ples of E. histolytica, which showed considerable intraspecific variability . (C) 2000 Elsevier Science B.V. All rights reserved.