REVEALING GENETIC MARKERS IN GELIDIUM VAGUM (RHODOPHYTA) THROUGH THE RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) TECHNIQUE

The recently developed random amplified polymorphic DNA technique was evaluated as a method for characterizing isolates of the agarophyte Gelidium vagum . Reaction conditions for single primer polymerase chain reaction were optimized to obtain a high degree of reproducibility of the amplified bands generated from purified G. vagum DNA. A total of 165 primers, including both (A + T)- and (G + C)-rich sequences, was screened for DNA amplification using template DNA from a single Gelidium isolate. None of the 45 (A + T)-rich primers was positive (i.e. band-producing). Of the (G + C)-rich primers, 47 were positive, generating a total of 322 prominent amplification products for DNA from 13 different G. vagum isolates. Polymorphic DNA loci were detected by 37 of the primers. Unweighted pair-group arithmetic average cluster analysis (UPGMA) of these loci was used to group the G. vagum isolates and thereby determine which were most similar. G. latifolium , used as an outgroup for the UPGMA analysis, showed a high degree of dissimilarity.