Assessing the genetic divergence of Pinus leucodermis Ant. endangered populations: use of molecular markers for conservation purposes

In this study, 23 previously identified Mendelian RAPD markers and 16 polymorphic allozymic markers were used to assess divergence among two Greek populations and five Italian populations of Pinus leucodermis. Confidence intervals of observed genetic divergence were obtained using bootstrap analysis. Divergence among Italian populations was found to be about as large as that between Italian and Greek populations. Since it is likely that the split of two nuclei took place more than 10,000 years ago, a larger differentiation between, rather than within, the above nuclei was expected. If genetic drift was responsible for the larger divergence of Italian populations, large randomly generated disequilibrium between alleles at neutral, unlinked loci was expected. Indeed, the proportion of pairs of loci showing a non-random association of alleles within each of the Italian populations was larger than what was expected by pure chance (7.95-10.88%). Effective population size based on randomly generated disequilibrium was quite small for three out of the five populations considered (Ne, = 17.31 +/- 1.88, 16.57 +/- 1.73, and 31.41 +/- 7.26, respectively). The implications of the results with respect to the conservation of endangered species of trees are discussed.