Submitted to: Solanaceae International Congress Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 5/29/2006
Publication Date: 7/30/2006
Citation: Rodriguez, F., Wu, F., Tanksley, S., Spooner, D.M. 2006. A multiple single-copy gene phylogenetic analysis of wild tomatoes (solanum l. section lycopersicon (mill.) wettst.) and their outgroup relatives [abstract]. Solanaceae International Congress Proceedings. p. 158. Interpretive Summary:
Technical Abstract: We examined the phylogenetic utility of conserved orthologous sequences (COS markers) in 22 diploid Solanum species, to include ten species of wild tomatoes (section Lycopersicon), their four outgroup species in sections Juglandifolium and Lycopersicoides, six species of wild potatoes (section Petota), one species each in sections Etuberosum and Dulcamara; one species of Datura was used as outgroup. We chose the sequences by distribution throughout all linkage groups of tomato, different functional gene classes, and a mixture of intronic (74%) and exonic (26%) regions. To date, we have sequenced, aligned, and phylogenetically analyzed (maximum parsimony and maximum likelihood) these species for 19 COS sequences. They had an average aligned length of 920 bp, for a total concatenated aligned length of 17,484 bp. Maximum parsimony and maximum likelihood topologies are identical and produced tomato and potato ingroup results entirely in concordance with prior GBSSI sequence data for tomatoes (published) and potatoes (unpublished) except COS showed greatly increased resolution. Outgroup results were similar, but not entirely concordant with prior GBSSI and chloroplast DNA restriction site phylogenies. For example, COS placed sect. Lycopersicoides sister to tomatoes, in contrast to section Juglandifolium in GBSSI, and sect. Etuberosum was sister to tomatoes, sect. Lycopersicoides and section Juglandifolium rather than sister to tomatoes and potatoes. We reanalyzed the data by eliminating seven COS that showed poor resolution within any individual COS. This 12 COS dataset placed sect. Etuberosum sister to tomatoes and potatoes (but the position of sect. Juglandifolium remained unchanged). These results suggest that these markers are more useful for groups of related species, but COS with greater exon content may be more useful for wider phylogenetic analyses. We are continuing to sequence additional COS and will present additional results at the meeting.