Restriction Fragment Length Polymorphism (RFLP) in Palm wine Yeast Taxonomy

Abstract

Reports on the number of isolates and yeast species obtained from palm wine samples have differed very widely. One factor that probably accounts for this is the method of phenotypic discontinuity which has exclusively been employed in palm wine yeast speciation. The phenotypic features used mainly for this kind of speciation have been shown to be unstable. Consequently it was decided to employ the more consistent; and reliable method of Restriction Fragment Length Polymorphism (RFLP) to ascertain the veracity or otherwise of the literature reports on palm wine yeast isolates. Out of the ten palm wine yeast samples carefully selected from different localities in Southern Ghana, nine showed only one yeast isolate while the tenth sample (from Legon village) showed two isolates. All the yeast isolates were identified as Saccharomyces cerevisiae. The genomic DNA restriction fragment patterns of all the palm wine yeast isolates were examined following the isolation and purification of their DNAs, restriction enzyme digestion of the isolated DNAs, and 0.7% agarose gel electrophoresis at 100 V for 1.3 hours. While the nine isolates PW/B/1, PW/B/2 through to PW/B/9, showed identical patterns, irrespective of any of the seven restriction endonuclease enzymes, Apa I, BamH I, EcoR I, Hind III, Kpn I, Psl I and Sma I used, the patterns of the two isolates from Legon differed slightly from the other nine, but were identical to each other. From these results, it was concluded that isolates PW/B/1, PW/B/2 through to PW/B/9, are the same species, while the other two, PW/B/lOa and PW/B/lOb are either subspecies or strains of these nine.