Genetic variation in natural and planted populations of Shorea guiso (Dipterocarpaceae) in the Philippines revealed by microsatellite DNA markers

Abstract

The genetic diversity of four natural and four planted populations of Shorea guiso in the Philippines were investigated using microsatellite DNA markers to compare patterns of variation within and among the populations. Leaf samples were collected from trees in eight sites and three islands in the archipelago and extracted for genomic DNA. Six microsatellite markers previously developed for two species of Shorea and found polymorphic in Shorea guiso were used in this study. We employed standard genetic diversity measures for microsatellite markers to quantify genetic variation. Results indicate a high level of genetic diversity within populations of S. guiso. The natural populations in Bohol (N_BOH) showed the highest genetic diversity among the four natural populations followed by Makiling (N_MFR), Tanay, Rizal (N_TAR) then Subic (N_SUB). Among the planted populations, Bislig (P_BIS) contained the highest genetic diversity followed by Bayombong, Nueva Vizcaya (P_BNV), P_MFR and P_BOH. An AMOVA revealed high variation within populations (95.39%) and low variation among planted populations (4.61%). Further, an AMOVA among both population types (natural and planted) revealed no differentiation (-0.80%) among the groups, 5.2 % of variation occurred among populations within groups and 95.6% variation within populations. The largest genetic distance was found between the natural populations N_BOH/N_SUB (0.332) and the smallest was between N_MAK/P_MAK from both population types (0.041). Small genetic distances indicating high genetic similarities were also observed between N_TAR/N_SUB (0.044); P_BNV/N_TAR (0.060); P_BIS/P_BNV (0.072); and P_BIS/P_MAK (0.091). This study proves the usefulness of microsatellite markers in the assessment of genetic variation within and among populations and determination of the origin of the planted populations.