No abstract

Nothotsuga longibracteata, a relic and endangered conifer species endemic to subtropical China, was studied for examining the spatial-temporal population genetic variation and structure to understand the historical biogeographical processes underlying the present geographical distribution. Ten populations were sampled over the entire natural range of the species for spatial analysis, while three key populations with large population sizes and varied age structure were selected for temporal analyses using both nuclear microsatellites (nSSR) and chloroplast microsatellites (cpSSR). A recent bottleneck was detected in the natural populations of N. longibracteata. The spatial genetic analysis showed significant population genetic differentiation across its total geographical range. Notwithstanding, the temporal genetic analysis revealed that the level of genetic diversity between different age class subpopulations remained constant over time. Eleven refugia of the Last Glacial Maximum were identified, which deserve particular attention for conservation management.

Twelve polymorphic microsatellite loci were isolated and characterized from an ACenriched genomic library of Nothotsuga longibracteata . The average allele number of these microsatellites was 8.3 per locus, ranging from two to 13. The ranges of observed and expected heterozygosities were 0.03 -0.97 and 0.09 -0.88, respectively. These polymorphic markers provide useful tools for the study of evolutionary history and conservation genetics of N. longibracteata .