Two genetic divergence centers revealed by chloroplastic DNA variation in populations of Cinnamomum kanehirae Hay

Abstract

Cinnamomum kanehirae Hayata (Lauraceae), the most valuable subtropical and temperate broadleaf timber tree in Taiwan, is rapidly disappearing from the wild. Taking advantage of a scion garden established by the Taiwan Forestry Research Institute, we examined patterns of chloroplast DNA (cpDNA) variations in 19 populations including 94 individuals. By sequencing two cpDNA fragments using universal primers (the trnL-trnF and petG-trnP intergenic spacers), we found eight polymorphic sites, six haplotypes, and extremely low nucleotide diversity (p = 0.00016) from 792 bp aligned sequences. The ancestral haplotype is widely distributed. Among the populations studied, three separated populations, at Yungfeng, Fuli, and Tahu have high nucleotide diversity. No phylogeographical structures of haplotypes were revealed because the tests of N ST -G ST for populations did not differ from zero in any situations; a 'star-like' genealogy is characteristic when all haplotypes rapidly coalesce and is a general outcome of population expansion. The neutrality test also suggested demographic expansion. The genetic divergence and diversity analyses suggested that two potential refugia existed during the last glaciation with a major one located in southeastern Taiwan and a minor one located in Tahu in north-central Taiwan in the Hsuehshan Range, west of the Central Mountain Range.

Tracking the geographical origin of timber by DNA fingerprinting: a study of the endangered species Cinnamomum kanehirae in Taiwan

“…The lower level of genetic diversity in C. kanehirae is the result of the stochastic losses of genetic polymorphisms. This observation is consistent with the results of Kuo et al (2010) and Liao et al (2010) studies. Positive F IS were found in all populations except LI, which is interpreted that inbreeding may have also contributed to the decrement of genetic diversity of C. kanehirae.…”

“…The intergenic spacer between trnL (UAA) 3′exon and trnF (GAA) (Taberlet et al 1998;Kuo et al 2010) was amplified and sequenced according to Kuo et al (2010). Three randomly chosen PCR products from wood samples were purified and sequenced by means of an automated sequencer (Applied Biosystems Model 377A).…”

“…This also leads to a decrease of genetic variation and population structure. Kuo et al (2010) examined the genetic patterns of cpDNA in C. kanehirae and found that its genetic variation is smaller than that of other tree species in Taiwan, which is also manifest in its nuclear genes (Liao et al 2010).…”

Historical connectivity, contemporary isolation and local adaptation in a widespread but discontinuously distributed species endemic to Taiwan, Rhododendron oldhamii (Ericaceae)

“…Multiple postglacial migration sources are common in many plant species in Taiwan, because plant species retreated into refugia in different geographic areas (Wu et al, 2006;Kuo et al, 2010). Our population estimates of y from MIGRATE-N ranged 0.62-0.99 (Supplementary Figure 2a-c), which are comparable to those of long-lived Eucalyptus (Field et al, 2011) and annual Helianthus species (Kane et al, 2009).…”

Historical spatial range expansion and a very recent bottleneck of Cinnamomum kanehiraeHay. (Lauraceae) in Taiwan inferred from nuclear genes

“…Population expansion after the LGM was inferred for several plant species including C. kanehirae based on cpDNA variations [21,37,40,81]. Further information on the demographic history of C. kanehirae was revealed by nuclear DNA variations.…”