Yufei Sun

Sun Yat-Sen University, Shengcheng, Guangdong, China

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Publications (4)1.83 Total impact

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    ABSTRACT: Apterosperma and Euryodendron, monotypic genera in Theaceae (sensu lato), are endemic and restrictedly distributed in south China. The two genera are not included in the major classification systems. However, their systematic position and origin have been subject to intense debate in the last decade. In this study, the phylogeny and divergence times of both Apterosperma and Euryodendron were inferred using combined dataset of chloroplast DNA trnL-F and atpB-rbcL non-coding sequences and nrDNA ITS sequences. The results from Bayesian inference, maximum parsimony, and maximum likelihood consistently showed that (i) Euryodendron is a valid genus, which is closer to Eurya than to Cleyera and (ii) Apterosperma is a genus of the tribe Theeae along with Tutcheria and Camellia. It was first reported that the divergence time of Apterosperma was 61.98 million years ago (mya), whereas that of Euryodendron 20.51 mya, indicating Tertiary origins in south China. The divergence of Apterosperma appears to be the result of increased ecological opportunity after Cretaceous/Tertiary extinction events and related with high temperatures and high humidity environments. By contrast, the origin of Euryodendron may be associated with historical mountain building events as well as the significant climate changes that established cooler temperatures prevailing until today.
    No preview · Article · Aug 2011 · Biochemical Systematics and Ecology
  • Yingjuan Su · Ting Wang · Yufei Sun · Huagu Ye
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    ABSTRACT: Euryodendron excelsum is a critically endangered Ternstroemiaceae species endemic to southern China, with only 14 individuals surviving in Ba Jia Zhen of Yangchun, Guangdong Province. Intersimple sequence repeat (ISSR) markers were used to assess genetic variation and relationships among these individuals. Population genetic parameters were estimated by a Bayesian approach as well as conventional methods. Of the 225 loci generated by 21 primers, 147 (65.33%) were polymorphic. Compared with other species of Theaceae and related families, a high level of genetic variation was identified in E. excelsum (Nei's gene diversity, 0.2458; Shannon's index, 0.3626). An unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed that the 14 individuals were mainly clustered into three groups, a conclusion further supported by principal coordinate analysis. Based on these results, a management and conservation strategy for E. excelsum was proposed.
    No preview · Article · Feb 2009 · Biochemical Genetics
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    ABSTRACT: This study determined the sequences of chloroplast DNA (cpDNA) trnL-F non-coding regions of individuals of a tropical coniferous species, Dacrydium pectinatum, collected from 12 natural populations located in Hainan Province, southern China. Sequence length varied from 868 bp to 876 bp, indicating length polymorphism. Base composition in the sequences was high in A+T content between 64.17% and 64.95%, and no recombination event occurred (Rm = 0). Thirty haplotypes were identified based on statistical parsimony algorithm by running the TCS program. Populations of D. pectinatum in Hainan were lacking genetic differentiation. Such a deduction was supported by the observed F ST values (0.00), AMOVA (24.17% of molecular variance attributed to difference among populations, P>0.05), high values of Nm (ranging from 1.92 to 2.50) and the branching structure in neighbor-joining (NJ) tree constructed from haplotypes. A ‘star-like’ pattern was exhibited in the TCS network of trnL-F haplotypes, and majority of the haplotypes coalesced near the tips in NJ tree. Gene genealogies of cpDNA haplotypes proposed a recent population expansion of D. pectinatum in Hainan, which was further supported by the results from Tajima’s D test and mismatch distribution analysis. Our data, in conjunction with geological and palynological evidences, showed that in the Holocene, due to global warming, refugee populations of D. pectinatum in Hainan might experience a range expansion.
    No preview · Article · Sep 2006 · Frontiers of Biology in China
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    ABSTRACT: Random amplification polymorphic DNA (RAPD) markers were used to assess the genetic variations and the evolutionary relationships among all 14 individuals of a critically endangered Euryodendron excelsum (Theaceae) population distributed in Ba Jia Zhen, Yangchun, Guangdong, China. Twenty-three random primers detected 156 sites, out of which 95 (60.26%) were polymorphic loci. The number of the observed alleles was 1.6090, and the number of the effective alleles was 1.3471. Nei’s gene diversity was 0.1993, and Shannon index was 0.1534. A relatively high level of genetic variation was identified in E. excelsum. An unweighted pair group method with arithmetic mean (UPGMA) tree established from Jaccard similarity coefficients suggested that 14 individuals were clustered into two subgroups and that the No. 2 plant was genetically distant from the rest of the individuals. The UPGMA clustering was also supported by a principle components analysis of RAPD phenotypic data. The management and conservation strategy of E. excelsum was proposed based on our results.
    No preview · Article · Jan 2006 · Frontiers of Biology in China