WOLF, PAUL G.1*, BERNARD DOCHE2, LUDOVIC GIELLY2, and PIERRE TABERLET2. 1Department of Biology, Utah State University, Logan, UT 84322, USA; 2Laboratoire de Biologie des Populations d'Altitude, Universite Joseph Fourier, Grenoble, France. - Genetic structure of alpine Rhododendron across a wide range of spatial scales.
Rhododendron ferrugineum L. (Ericaceae) is a subapline shrub found
throughout the Pyrenees and Alps, usually at elevations of 1600 – 2200
m. We used 115 dominant AFLP markers to assess genetic structure over
wide spatial scales, to gain insights into the relationships between
genetic and geographic distance. Leaf tissue was sampled from 10
plants from each of 17 sites across the species’ range, with the
maximum distance between sites of over 1000km. In addition, at two of
the sites we used transects to sample at distances ranging from 10m to
3000m. We found no distinct patterns in terms of the distribution of
polymorphic loci, so that it is not yet possible to distinguish
recently-colonized sites based on the effects of genetic drift. We
observed a positive relationship between genetic distance and spatial
distance at the small scales (10 – 1000m), but this breaks down at
greater geographic distances. However, there is considerable variation
among loci: at some loci, the dominant allele has a restricted
geographic range, whereas alleles at other loci are distributed more
continuously over the range. Overall patterns of genetic variation are
consistent with rapid postglacial colonization as well as high levels
of gene flow among sites.
Key words: AFLP, genetic distance, isolation by distance, Rhododendron ferrugineum