Population genetic structure and evolutionary history of Psammochloa
villosa (Trin.) Bor (Poaceae) revealed by AFLP marker
Abstract
We sought to generate a preliminary demographic framework for
Psammochloa villosa to support of future studies of this ecologically
important desert grass species, its conservation, and sustainable
utilization. Psammochloa villosa occurs in the Inner Mongolian Plateau
where it is frequently the dominant species and is involved in sand
stabilization and wind breaking. Here, we characterized the genetic
diversity and structure of 210 individuals from 43 natural populations
of P. villosa using amplified fragment length polymorphism (AFLP)
markers. We obtained 1728 well-defined amplified bands from eight pairs
of primers, of which 1654 bands (95.72%) were polymorphic.All these
values indicate that there is abundant genetic diversity, but limited
gene flow in P. villosa. However, an analysis of molecular variance
(AMOVA) showed that genetic variation mainly exists within 43
populations of the species (64.16%), and we found that the most
genetically similar populations were often not geographically adjacent.
Thus, this suggests that the mechanisms of gene flow are surprisingly
complex in the species and may occur over long distances. In addition,
we predicted the distribution dynamics of P. villosa based on the
spatial distribution modeling and found that its range has contracted
continuously since the last inter-glacial period. We speculate that dry,
cold climates have been critical in determining the geographic
distribution of P. villosa during the Quaternary period. Our study
provides new insights into the population genetics and evolutionary
history of P. villosa in the Inner Mongolian Plateau, which can be used
to design in-situ conservation actions and to prioritize sustainable
utilization of germplasm resources.