SPATIAL GENETIC STRUCTURE OF THE TALLGRASS PRAIRIE: GRASS DICHANTHELIUM OLIGOSANTHES (SCRIBNER’S PANICUM)

The spatial genetic structure within plant populations and genetic differentiation among populations can vary in strength due to the forces of natural selection, gene flow and genetic drift. In this study, we investigate the level of genetic structure and differentiation present in Oklahoma populations of Dichanthelium oligosanthes (Schult.) Gould (Scribner’s panicum), a C3 grass native to the United States and a frequent member of the tallgrass prairie. To examine fine-scale spatial genetic structure of D. oligosanthes, we collected leaves from 48 spatially separated plants in a population in Stillwater, OK. To examine genetic differentiation among adjacent populations, we sampled leaf tissue from eight individuals at each of three populations in Stillwater, OK. DNA was extracted from these samples and Inter-Simple Sequence Repeats (ISSR) markers were amplified. Within a single population of D. oligosanthes, we found a weak and non-significant negative relationship between genetic similarity and geographical distance. In contrast, we found evidence for moderate and significant genetic differentiation among populations.