Sciadopitys verticillata is amongst the most relictual of all plants, being the last living member of an ancient conifer lineage, the Sciadopityaceae, and is distributed in small and disjunct populations in high rainfall regions of Japan. Although mega-fossils indicate the persistence of the species within Japan through the Pleistocene glacial– interglacial cycles, how the species withstood the colder and drier climates of the glacials is not well known. The present study utilized phylogeography and palaeodistribution modelling to test whether the species survived within pollen-based coastal temperate forest glacial refugia or within previously unidentified refugia close to its current range. Sixteen chloroplast haplotypes were found that displayed significant geographical structuring. Unexpectedly, northern populations in central Honshu most distant from coastal refugia had the highest chloroplast diversity and were differentiated from the south, a legacy of glacial populations possibly in inland river valleys close to its current northern range. By contrast, populations near putative coastal refugia in southern Japan, harboured the lower chloroplast diversity and were dominated by a single haplotype. Fragment size polymorphism at a highly variable and homoplasious mononucleotide repeat region in the trnT-,i>trnL intergenic spacer reinforced the contrasting patterns of diversity observed between northern and southern populations. The divergent histories of northern and southern populations revealed in the present study will inform the management of this globally significant conifer.

Item Type:	Refereed Article
Keywords:	chloroplast DNA, inland refugia, Japanese temperate forest, Japanese umbrella pine, mitochondria, mononucleotide repeats, palaeodistribution modelling, pollen-based refugia
Research Division:	Biological Sciences
Research Group:	Genetics
Research Field:	Genetics not elsewhere classified
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Terrestrial biodiversity
UTAS Author:	Worth, JRP (Dr James Worth)
ID Code:	94727
Year Published:	2013
Web of Science® Times Cited:	12
Deposited By:	Plant Science
Deposited On:	2014-09-16
Last Modified:	2014-10-13
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