LARA-CABRERA, SABINA, CELESTE RAKER, and DAVID M. SPOONER.* USDA, Agricultural Research Service, Department of Horticulture, University of Wisconsin, Madison, WI 53706. - Utility of microsatellites in wild potatoes.
Solanum section Petota, the potato and its wild
relatives, contains over 200 wild species distributed from the
southwestern United States to central Argentina and adjacent Chile.
Many taxa are similar morphologically and may be conspecific. We
tested the phylogenetic utility of microsatellites in Solanum
tuberosum, the source of the microsatellite primers, and in
Mexican diploid species, the most distant clade to Solanum
tuberosum in sect. Petota. We used both an infinite allele
model and a step-wise mutation model with many tree building methods.
The infinite allele model and Neighbor Joining produced trees most
closely matching species boundaries and hypotheses of relationships,
but clustered taxa very poorly in the Mexican diploids. We sequenced
three microsatellite fragments from three species, and compared these
to sequences of S. tuberosum. There were many cases of
divergence among priming sites that explained some cases of
non-amplification. There also was much divergence of microsatellite
flanking sequences, showing non-homology of fragment sizes, explaining
their reduced phylogenetic utility in the Mexican diploids.
Key words: microsatellites, Petota, sequence, Solanaceae, Solanum, SSR