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

Abstract

BackgroundSpecies in the varied geographic topology of Taiwan underwent obvious demographic changes during glacial periods. Cinnamomum kanehirae has been exploited for timber and to obtain medicinal fungi for the past 100 years. Understanding anthropogenic factors influencing the demography of this species after the last glacial maximum (LGM) is critically important for the conservation of this species.ResultsPopulations of C. kanehirae were classified into four geographic regions: northwestern (NW), west-central (WC), southwestern (SW), and southeastern (SE). In total, 113 individuals from 19 localities were sampled, and variations in the chalcone synthase gene (Chs) intron and leafy (Lfy) intron-2 sequences of nuclear DNA were examined in order to assess phylogeographic patterns, the timescales of demographic and evolutionary events, and recent anthropogenic effects. In total, 210 Chs and 170 Lfy sequences, which respectively constituted 36 and 35 haplotypes, were used for the analyses. Estimates of the migration rate (M) through time revealed a pattern of frequent gene flow during previous and the present interglacials. The isolation-by-distance test showed that there generally was no significant correlation between genetic and geographic distances. The level of among-region genetic differentiation was significant when comparing eastern to western populations. However, no significant among-region genetic differentiation was found in comparisons among the four geographic regions. Moreover, essentially no genetic structuring was found for the three regions west of the CMR. A fit of spatial range expansion was found for pooled and regional samples according to the non-significant values of the sum of squared deviations. Using the Bayesian skyline plot (BSP) method, a recent bottleneck after the LGM expansion was detected in both regional and pooled samples.ConclusionsCommon haplotype distributions among geographic regions and the relatively shallow genetic structuring displayed are the result of historical gene flows. Southward dispersals in an earlier time frame from the NW region and in a later time frame from the SE region were inferred. The BSP analysis suggested a postglacial expansion event. Recent trends, however, refer to a bottleneck due to human interventions observed for both pooled and regional C. kanehirae samples.

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.…”

“…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).…”

Comparative analysis of the complete chloroplast genomic sequence and chemical components of Cinnamomum micranthum and Cinnamomum kanehirae

“…Plant material and DNA extraction: During winter (October-January) in Taiwan, 23 fresh leaf samples of C. micranthum were collected for chemical analyses from Taipei, Ilan, and Natou, while 23 C. kanehirae samples were collected from 13 sites throughout the Taiwan island, including sampling areas covered by previous studies (Lin 1993;Liao et al 2010). Wood materials (with height over 3 m) were collected from 12 individuals from Fushan Botanical Garden in Ilan and Liouguei Research Center in Kaohsiung city of Taiwan.…”

“…This tree is difficult to find in the wilderness because of its unrestrained illegal logging (Lin et al 1997;Hung et al 2014). Thus, C. kanehirae is an endangered wood species, which also plays an important economic and ecological role in Taiwan (Liao et al 2010;Cheng et al 2015).…”

“…Cinnamomum kanehirae is an endemic tree species and is one of the five most precious broadleaf wood species in Taiwan. Its wood is in high demand as it is the original host of the parasitizing fungus Antrodia cinnamomea, which is very expensive (US$10 000 per kilogram) and known to have anti-oxidative, anti-inflammatory, and anti-carcinogenic effects (Liao et al 2010;Lin et al 2011;Tzeng and Geethangili 2011). The health-promotion functions of the fungus are specifically connected to C. kanehirae as the growing substrate Chou 1995, 2004;Lin et al 2011) and produce ergostane-type triterpenoids and benzolics (Shen et al 2004;Lin et al 2011).…”