In situ and Ex situ Conservation of Commercial Tropical Trees - ITTO

309Genetic Structure of Natural Populations ofDryobalanops aromatica Gaertn. f. (Dipterocarpaceae)in Peninsular Malaysia Using Microsatellite DNAMarkersLIM L.S. 1 , WICKNESWARI R. 1 , LEE S.L. 2 & LATIFF A. 11)School of Environmental and Natural Resource Sciences 1Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 Bangi, Selangor Darul Ehsan, Malaysia2)Forest Research Institute Malaysia52109 Kepong, Selangor Darul Ehsan, MalaysiaAbstract. Nine microsatellite DNA markers developed for Shorea curtisii (i.e. Shc01, Shc02,Shc03, Shc04, Shc07, Shc08, Shc09, Shc11 and Shc17), and one developed for Dryobalanopslanceolata [DL(GT)202] were tested for cross-species specificity on D. aromatica. The primerdeveloped for D. lanceolata showed no amplification in D. aromatica. Although all the primersdesigned for S. curtisii gave amplifications, primer Shc01 and Shc08 yielded many non-specificbands. The other seven codominant microsatellite DNA loci were used to assess the geneticvariation of D. aromatica from five populations in Peninsular Malaysia, namely Lenggor andUlu Sedili (Johore), Lesong (Pahang), Kanching (Selangor) and Bukit Sai (Terengganu). Theexpected mean genetic diversity (H e) was high (0.709) with values ranging from 0.684 (Lenggor)to 0.735 (Lesong). Most of the populations showed high and positive fixation indices, indicatingan excess of homozygotes. This implies a high level of inbreeding that may be caused by selfingor/and mating between closely related individuals. A gene diversity analysis showed that 93.3%of the observed genetic diversity was contained within populations and 6.7% (G ST= 0.067) wasdue to difference between populations. The smallest genetic distance (D) was between Bukit Saiand Lesong (0.068), and the largest between Ulu Sedili and Lesong (0.477). Mean gene flow(Nm) was high (2.94), with the highest value being between Lenggor and Bukit Sai (-6.98). Thelowest gene flow occurred between Kanching and Ulu Sedili (1.95). The findings from this studyimply that the four natural populations of D. aromatica on the east coast of Peninsular Malaysiamay have been a single unfragmented population in the recent past. The results of this study alsosupport an earlier alternative hypothesis that the Kanching population on the west coast ofPeninsular Malaysia originated from the east coast populations. This is supported by thedendrogram derived from the UPGMA cluster analysis of genetic distances, in that the Kanchingpopulation is closely related to the Lesong and Bukit Sai populations from the east coast.