Fairservice, J.H., M.D. Peters, C.L. Turner, J.A. Clevinger, and C.K. McMullen. 2002. A phylogenetic study of Alternanthera (Amaranthaceae) in the Galápagos Islands using DNA sequences and ISSR banding patterns.

Presentation Abstract: Fourteen species of chaff flower, Alternanthera, inhabit the Galápagos Islands; six are endemic, four are native and four are introduced weeds. This study will use molecular techniques to create a phylogeny of this group, thus allowing us to clarify the relationships among these species and their mainland sister taxa. Currently, two regions of nuclear DNA and chloroplast DNA have been sequenced. Preliminary analysis, however, indicates that these sequences do not contain sufficient variation to resolve all relationships. Therefore our lab is using an inter-simple sequence repeat (ISSR) assay, which is a new PCR based technique that can assess variation between natural populations. ISSR primers are designed from 1-6 nucleotide tandem repeats, called microsatellites, scattered throughout the genome of most organisms. Numerous ISSR primers designed by Dr. Andrea Wolfe (Ohio State University) are being screened for their usefulness to the project. ISSR based PCR products are visualized using standard ethidium-stained agarose gels. The resulting banding patterns are being scored and this data will then be used to construct a neighbor joining tree to access relationships.