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 char acterize 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 oligonucleoti de primers, all (G+C)-rich, were positive or band-producing, but yield ed poor or variable band resolution. Subsequent use of the universal 2 0-mer M 13 primer resulted in both clear band resolution with a minimu m of secondary bands and a high degree of reproducibility. Amplificati on products for DNA from six regional isolates of Porphyra carolinensi s Coll et Cox, P. leucosticta Thuret in Le Jolis and P. rosengurttii C oll et Cox were compared to each other and to Bangia atropurpurea (Rot h) 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 specifi c genotypes. This procedure could be used to discriminate between hete ro- and homokaryotic fusion products from previously characterized don or strains.