RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) IDENTIFICATION OF GENETIC-VARIATION IN 3 SPECIES OF PORPHYRA (BANGIALES, RHODOPHYTA)

The random amplified polymorphic DNA (RAPD) technique was used to characterize three species of Porphyra from the western North Atlantic and adjacent Gulf of Mexico. Twenty 10-mer primers were screened for DNA amplification using Porphyra template DNA. Nine of these oligonucleotide primers, all (G+C)-rich, were positive or band-producing, but yielded poor or variable band resolution. Subsequent use of the universal 20-mer M 13 primer resulted in both clear band resolution with a minimum of secondary bands and a high degree of reproducibility. Amplification products for DNA from six regional isolates of Porphyra carolinensis Coll et Cox, P. leucosticta Thuret in Le Jolis and P. rosengurttii Coll et Cox were compared to each other and to Bangia atropurpurea (Roth) C. Agardh. Results provide evidence of both genetically hetero- and homogeneous populations. Use of the RAPD method with the M 13 primer yields amplification products which can be used to fingerprint specific genotypes. This procedure could be used to discriminate between hetero- and homokaryotic fusion products from previously characterized donor strains.