Revealing the Genetic Structure of Indonesia Moluccan Dipterocarps Species, Rubroshorea selanica

Abstract

Among the species within the Dipterocarpaceae family, Rubroshorea selanica (Valmont) P.S. Ashton & J. Heck. is a rare instance of the Rubroshorea species that spans its distribution eastward across the Wallace Line. R. selanica is grouped into the genus of Rubroshorea and is also known as Red Meranti for its timber color. The species is exclusively located within the central region of the Moluccas, encompassing Buru Island, Sula Island, Obi Island and Seram Island. Our research involved sequencing two non-coding regions of chloroplast DNA and three nuclear genes to analyze the genetic variation and structuring of this species. Nucleotide diversity (π) in the intergenic spacers of chloroplasts within populations showed no variation (0) for Seram population to the highest of 0.00044 for Buru population, with an overall value of 0.00041 for the combined population. Diversity of nucleotides in non-coding regions (πsil) within the nuclear gene exhibited variability across the three examined loci, ranging from the highest of 0.02034 for GBSSI to the lowest of 0.00450 for GapC. We observed significant population structuring for the chloroplast DNA regions (FST = 0.702) and two out of the three nuclear gene loci studied (FST = 0.369 and 0.415 for GBSSI and PgiC), suggesting that every population is unique and, as a result, carries its own importance. as a conservation unit.