Ho Wei Seng (UNIMAS), Awang Ahmad Sallehin Awang Husaini (UNIMAS), Hairul Azman @ Amir Hamzah Roslan, Cheksum Tawan (UNIMAS), Isa Ipor (UNIMAS), Yii Ai Siew (UNIMAS)
Belian or its popular name, Borneo Ironwood, is the most famous and well-known durable hardwood timber tree of Borneo, which comes from the family Lauraceae. There are two species of Belian, i.e. Eusideroxylon zwageri and Potoxylon malagangai.
Both species have a very close similarity in their vegetative characters except the wood structure. P. malagangai has lighter colour of wood and lower durability compared to E. zwageri. Thus, it is not easy to distinguish the two species based on their vegetative characters when in the field.
To date, little genetic information is available on these valuable timber species, and therefore the belian must be studied thoroughly using molecular techniques to identify genetic variation within and among belian populations in order to conserve the rapidly declining belian populations in Sarawak.
The characterization of genetic variation is central to the conservation of genetic diversity in natural or domesticated populations. Populations with little genetic variation are more vulnerable to the arrival of new pests or diseases, pollution, changes in climate and habitat destruction due to human activities or other catastrophic events.
The inability to adapt to changing conditions greatly increases the risk of extinction. Moreover, the belian has been counted as one of the endangered species in Sarawak.
The objectives of this study are to genotyping belian via PCR-based molecular marker techniques, and to develop species-specific genetic markers (sequence characterised amplified regions, SCARs) for identification of belian. The identification of individuals at species level constitutes one of the first basics in any effective conservation programme.
Besides these, the genetic diversity of belian populations will also be determined using molecular marker techniques such as isoenzymes, Restriction Fragment Length Polymorphisms via PCR (PCR-RFLPs), Random Amplified Polymorphic DNAs (RAPDs), Directed Amplification of Minisatellite-region DNA (DAMD), Inter-Simple Sequence Repeats (ISSRs) and Simple Sequence Repeats (SSRs). The choice of molecular markers is largely dependent on the level of polymorphism to be detected and the genomic coverage of molecular marker.
Ho, W.S., Yii, A.S., Cheksum, T. 2005. Genotyping of Borneo Ironwood (Belian) using polymerase chain reaction with the M13 universal primer.