Systematics/Phytogeography / Taxonomie/ Section
Rodriguez, F. , Spooner, David M. .
Do potatoes and tomatoes have a single evolutionary history? What proportion of the genome supports this history?
A paucity of validated nuclear orthologs for phylogenetic studies has resulted in a situation where most molecular taxonomic studies rely heavily on a few plastid and/or ribosomal genes. Phylogenies reconstructed with only one or a few independently inherited loci may be unresolved or incongruent due to taxon and gene sampling, horizontal gene transfer, or differential selection and lineage sorting at individual loci. We examined the utility of conserved orthologous sequences (COS markers) to elucidate the phylogenetic relationships among a total of 35 diploid Solanum species in the sister clades tomato (13 species), potato (14), section Etuberosum (2), section Juglandifolium (2), section Lycopersicoides (2), S. dulcamara; one species of the genus Datura was used as outgroup. We have screened 88 COSII markers with intron content over 60% and located in different chromosomes; selected a subset of 48 out of them by the presence of single band amplification of size between 600 and 1200; sequenced 23 of these; and performed phylogenetic analyses of the concatenated dataset. Results are entirely in concordance with prior analyses of GBSSI sequence data, but with a significant increase in resolution among closely related species. We aim to use Bayesian Concordance Analysis to identify the “primary concordance tree” that summarizes the dominant phylogenetic history shared among the taxa under study, and estimate the proportion of the genome that supports that history.
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1 - University of Wisconsin Madison, Horticulture Department, 1575 Linden Dr., Madison, Wisconsin, 53706-1590, USA
2 - USDA, Agricultural Research Service, Horticulture, University of Wisconsin, 1575 Linden Drive, Madison, WI, 53706-1590, U.S.A.
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, July 30th, 2008
Time: 2:15 PM