Development and technical application of SSR-based individual identification system for Chamaecyparis taiwanensis against illegal logging convictions

Chamaecyparis taiwanensis is an endemic plant suffering illegal logging in Taiwan for its high economic value. Lack of direct evidence to correlate stump and timber remains a hurdle for law enforcement. In this report, 23 polymorphic Genomic Simple Sequence Repeat (gSSR) and 12 Expressed Sequence Tag (EST)-SSR markers were developed and their transferability was assessed. The individual identification system built from selected non-linkage 30 SSR markers has a combined probability of identity as 5.596 × 10-12 equivalents to identifying an individual in a population of up to 18 million C. taiwanensis with 99.99% confidence level. We also applied the system in an actual criminal case by selecting 19 of these markers to correlate illegally felled timbers and victim trees. Our data demonstrate that molecular signals from three timbers hit with three victim trees with confidence level more than 99.99%. This is the first example of successfully applying SSR in C. taiwanensis as a court evidence for law enforcement. The identification system adapted advanced molecular technology and exhibits its great potential for natural resource management on C. taiwanensis.