MOLECULAR PHYLOGENY OF MANGROVES .1. USE OF MOLECULAR MARKERS IN ASSESSING THE INTRASPECIFIC GENETIC-VARIABILITY IN THE MANGROVE SPECIES ACANTHUS-ILICIFOLIUS LINN (ACANTHACEAE)

Mangroves, the intertidal ecosystems occurring primarily in the tropic al regions of the world, are valuable natural resources with high prod uctivity and unique habitat value. However, the genetic structure of p lant species within the mangrove ecosystem is poorly understood. The p resent communication is the first report on the use of molecular marke rs in assessing intra-site and intra-specific polymorphism in one of t he mangrove species, Acanthus ilicifolius, for identifying/detecting d istinct genotypes for long-term conservation. Random amplified polymor phic DNAs (RAPDs) and restriction fragment length polymorphisms (RFLPs ) were used to elucidate the intra- and inter-population variability i n this widely distributed mangrove species. In all, 48 genotypes repre senting eight distinct populations were analysed. A low level of polym orphism was detected at the intra-population level through both RAPD ( 3.8-7.3%) and RFLP (3.2-9.1%) analyses. At the inter-population level, 25 of the 73 RAPD loci (34%) detected through the use of 13 random pr imers and 44 of the 96 RFLP loci (45.8%) revealed through 15 probe/enz yme combinations were polymorphic. RFLP analyses were carried out usin g genomic clones developed from the same species. The somatic cells of the species displayed 48 chromosomes, with no numerical changes at ei ther intra- or inter-population levels.