Cross-Species Amplification of Shorea Microsatellite DNA Markers in Parashorea malaanonan (Dipterocarpaceae)
Sixteen (16) microsatellite DNA markers previously developed for two Bornean species of Shorea (Dipterocarpaceae), viz. 5 from Shorea curtisii (Shc) and 11 from Shorea leprosula (Sle), were tested on Philippine Parashorea malaanonan for cross-species amplification. Initially, these loci were tested in Parashorea malaanonan from the Makiling Forest Reserve on Luzon Island. All five Shc loci had amplification products, three (3) were polymorphic and two (2) were non-polymorphic. Of the 11 Sle loci, five (5) were polymorphic, three (3) were non-polymorphic, two (2) did not have amplification products, and one (1) had multiple bands. Four loci were further tested on individuals of Parashorea malaanonan from a plantation on Leyte Island. High levels of genetic variability were observed. Cross-transferability was 75%. Expected heterozygosity (He) ranged from 0.39 to 0.82. Results indicate potential use of these markers derived from Shorea in studies of genetic diversity assessments in Parashorea malaanonan.
Parashorea malaanonan (Blanco) Merr. is one of about 45 species of the timber family Dipterocarpaceae thus far recorded from the Philippines (Ashton 1982; Newman et al. 1996). It is known from at least 10 of the larger islands in the Philippine archipelago and also from the northeast of Borneo (Newman et al. 1996; Ashton 2004). The species is common in lowland forests and occurs up to 1300 m alt. One recent study has characterized the mating system and assessed the genetic diversity of this species using isozymes (Gamboa-Lapitan and Hyun 2005). In most dipterocarps, genetic variation within species is largely unknown. Isozymes have been used in assessing population variation in Stemonoporus oblongifolius Thw. by Murawski and Bawa (1994), Lee et al. (2000a) in Shorea leprosula Miq., and Lee et al. (2000b) in Dryobalanops aromatica Gaertn.f. Cao et al. (2006) used amplified fragment length polymorphism (AFLP) to determine genetic diversity and differentiation among Indonesian populations of Shorea leprosula and Shorea parvifolia Dyer. Microsatellite DNA markers have previously been used by Konuma et al. (2000) and Nagamitsu et al. (2001) in analyses of dipterocarp breeding systems and genetic diversity assessments.