ABSTRACT
Aquilaria malaccensis (Thymelaeaceae) is the main source of high-grade agarwood in Southeast Asia. Aggressive collections and trade activities over the past decades have put great pressure on the natural stands and raised concerns over the long-term survival potential of A. malaccensis. Tracking and authentication of agarwood require method with a high degree of accuracy. Therefore, this study aimed to develop DNA databases of A. malaccensis as the tracking tools at species, population and individual levels for forensic identification and chain of custody certification. Using two cpDNA (rbcL and matK) and an rDNA (ITS2) markers, species identification database of Aquilaria was developed to distinguish A. malaccensis from A. hirta, A. microcarpa, A. beccariana, A. crassna, A. sinensis and A. rostrata. In addition, based on 35 populations of A. malaccensis throughout Peninsular Malaysia, cpDNA haplotype and STR allele frequency databases were developed for population and individual identification. A haplotype distribution map based on 29 haplotypes derived from seven cpDNA showed that the A. malaccensis in Peninsular Malaysia can be associated to Kedah-Perak and Kelantan-Johor regions. Similarly, genetic relatedness and Bayesian clustering analyses based on 10 STR markers also divided the 35 populations into two main genetic clusters, corresponding to Kedah-Perak and Kelantan-Johor regions. The STR allele frequency databases were established and characterized according to these two regions. To determine the performance of the STR allele frequency databases for population identification, independent self-assignment tests showed that the percentage of individuals correctly assigned into the origin population was 93.88% in Kedah-Perak and 90.29% in Kelantan-Johor. For the STR allele frequency databases to be used for individual identification, conservativeness tests showed that the θ should be adjusted to 0.250 and 0.200 in the Kedah-Perak and Kelantan-Johor databases, respectively. To ensure consistency in allele calling for the dinucleotide repeat loci across different electrophoretic platforms or laboratories, allelic ladders have been developed for the 10 STR loci. Two case studies are presented of how these databases were used to track A. malaccensis to the origin population and stump. These databases are ready to be used to provide admissible forensic evidence for legal proceedings against the illegal harvesters of agarwood and for agarwood certification to meet the consumer country regulations.
Subject(s)
Thymelaeaceae , Bayes Theorem , Certification , DNA, Chloroplast/genetics , Databases, Nucleic Acid , Humans , Thymelaeaceae/geneticsABSTRACT
The genus Senyumia was previously known from a single species, S.minutiflora (Ridl.) Kiew, A.Weber & B.L.Burtt, from a limestone karst, Gunung Senyum, in Pahang, Malaysia. Senyumiagranitica Kiew, here described and illustrated, is the second species of the genus. It differs from S.minutiflora, not only in its habitat, but also in its shorter leaves, larger, non-resupinate or only partially resupinate flowers and smaller seeds. It is known from a small, fragmented population from a low range of hills. Therefore, under the IUCN Red List Categories & Criteria, it is assessed as Critically Endangered.
ABSTRACT
PREMISE OF THE STUDY: Aggressive collections and trade activities in recent decades have resulted in heavy pressure on the natural stands of Aquilaria malaccensis and concerns over its long-term survival potential. To aid DNA profiling and assessment of its genetic diversity, microsatellite markers were developed for the species. METHODS AND RESULTS: Seventeen polymorphic microsatellite markers were developed for A. malaccensis using an enrichment protocol. The markers were screened on 24 samples from a natural population. The number of alleles ranged from two to 11, and the observed heterozygosity ranged from 0.042 to 0.957. No significant deviation from Hardy-Weinberg equilibrium was detected after conservative Bonferroni correction. CONCLUSIONS: This is the first report on the development of microsatellite markers in A. malaccensis. The markers will be used to establish a DNA profiling database and to estimate the genetic diversity and population genetic structure of the species.
