Low genetic diversity and significant population structuring in the relict Amentotaxus argotaenia complex (Taxaceae) based on ISSR fingerprinting

Xue Jun Ge, Xian Long Zhou, Zhong Chao Li, Tsai Wen Hsu, Barbara A. Schaal, Tzen Yuh Chiang

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

Amentotaxus, a genus of the Taxaceae, represents an ancient lineage that has long existed in Eurasia. All Amentotaxus species experienced frequent population expansion and contraction over periodical glaciations in Tertiary and Quaternary. Among them, Amentotaxus argotaenia complex consists of three morphologically alike species, A. argotaenia, Amentotaxus yunnanensis, and Amentotaxus formosana. This complex is distributed in the subtropical region of mainland China and Taiwan where many Pleistocene refugia have been documented. In this study, genetic diversity and population structuring within and between species were investigated based on the intersimple sequence repeats (ISSR) fingerprinting. Mean genetic diversity within populations was estimated in three ways: (1) the percentage of polymorphic loci out of all loci (P) (2) Nei's unbiased expected heterozygosity (He), and (3) Shannon's index of phenotypic diversity. For a total of 310 individuals of 15 populations sampled from the three species, low levels of ISSR genetic variation within populations were detected, with P = 4.66-16.58%, He = 0.0176-0.0645 and Hpop = 0.0263-0.0939, agreeing with their seriously threatened status. AMOVA analyses revealed that the differences between species only accounted for 27.38% of the total variation, whereas differences among populations and within populations were 57.70 and 14.92%, respectively, indicating substantial isolation between the patch-like populations. A neighbor-joining tree identified a close affinity between A. yunnanensis and A. formosana. Genetic drift due to small population size, plus limited current gene flow, resulted in significant genetic structuring. Low levels of intrapopulational genetic variation and considerable interpopulational divergence were also attributable to demographic bottlenecks during and/or after the Pleistocene glaciations.

Original languageEnglish
Pages (from-to)415-422
Number of pages8
JournalJournal of Plant Research
Volume118
Issue number6
DOIs
Publication statusPublished - 2005 Dec 1

All Science Journal Classification (ASJC) codes

  • Plant Science

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