Genetic structure of Potentilla acaulis (Rosaceae) populations based on randomly amplified polymorphic DNA (RAPD) in habitat fragmented grassland of northern China
Potentilla acaulis Linn. (Rosaceae) is an important companion species in central Asia steppe. However, no information was so far detected about genetic diversity of this species. In recent years, effects of habitat fragmentation have become central issues in conservation genetics. In order to evaluate the genetic structure and to measure the effects of isolation caused by habitat fragmentation, the randomly amplified polymorphic DNA (RAPD) data were generated and analyzed from 110 samples collected from seven sites of local populations of P. acaulis distributed in northern China. Eleven RAPD primers produced a total of 61 unambiguous bands, of which 51 bands (83.6%) were polymorphic. A high level of genetic diversity was recognized within the populations of P. acaulis: 34.4 to 68.9% of polymorphic bands observed in the given population. Analysis of molecular variance (AMOVA) showed that, genetic variability was greater within populations (83.4%) than among populations within regions (12.0%) or among regions (4.6%) investigated in this study. In addition, a low degree of genetic differentiation (ΦST= 0.17) was detected among all populations, which indicated that isolation had weak effects on genetic structure. The statistical analysis also revealed that, the genetic distances of P. acaulis among different populations were not significantly related with their geographic distances. Therefore, P. acaulis should be treated as a separate species that needs more attention from a conservation point of view and it should be considered as a conservation strategy to increasing gene exchange among isolated populations.
Key words: Potentilla acaulis Linn. (Rosaceae), steppe, habitat fragmentation, genetic diversity.