Assessment of genetic variation and clonality in the seagrass Posidonia australis using RAPD and allozyme analysis

The genetic structure of a meadow of Posidonia australis Hook. f . , an endemic seagrass from southern Australian coasts, was investigated at Warnbro Sound, Western Australia. A high level of genetic vanation as determined by allozyme and RAPD (random amplified polymorphic DNA) analyses was found within a small area of the meadow Allozyme analysis identified 15 four-locus genotypes from 43 samples (35%). RAPD analysis identified 16 four-primer genotypes from 22 samples (73 %). The levels of genetic variation in P. australis are equivalent to or greater than that observed in other hydrophilous species. The intrapopulational genetic variation demonstrated in this study shows that meadows of P. australis need not be monoclonal in all cases.