MOLECULAR ANALYSIS OF RAPD DNA-BASED MARKERS - THEIR POTENTIAL USE FOR THE DETECTION OF GENETIC-VARIABILITY IN JOJOBA (SIMMONDSIA-CHINENSISL SCHNEIDER)

We have applied the recently developed technique of random amplified p olymorphic DNA (RAPD) for the discrimination between two jojoba clones at the genomic level. Among a set of 30 primers tested, a simple repr oducible pattern with three distinct fragments for clone D and two dis tinct fragments for clone E was obtained with primer OPB08. Since RAPD products are the results of arbitrarily priming events and because a given primer can amplify a number of non-homologous sequences, we wond ered whether or not RAPD bands, even those of similar size, were deriv ed from different-loci in the two clones. To answer this question, two complementary approaches were used: i) cloning and sequencing of the amplification products from clone E; and ii) complementary Southern an alysis of RAPD gels using cloned or amplified fragments (directly reco vered from agarose gels) as RFLP probes. The data reported here show t hat the RAPD reaction generates multiple amplified fragments. Some fra gments, although resolved as a single band on agarose gels, contain di fferent DNA species of the same size. Furthermore, it appears that the cloned RAPD products of known sequence that do not target repetitive. DNA can be used as hybridization probes in RFLP to detect a polymorph ism among individuals.