Sounds interesting. If you attend could you forward us either data supplied or possibly a summary of what you thought? Thanks Andrew Wilson, San Diego -----Original Message----- From: pbs-bounces@lists.ibiblio.org [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of John T Lonsdale Sent: Monday, November 01, 2010 11:01 AM To: 'Pacific Bulb Society'; 'Trillium Enthusiast Discussion List (and other Woodland plants)' Subject: [pbs] FW: Penn Bioinformatics Forum -- Wed. November 10th with Dr.Michael Cummings The information below might be of interest: Penn Bioinformatics Forum Dr. Michael Cummings Associate Professor Center for Bioinformatics and Computational Biology University of Maryland Wednesday, November 10, 2010 CRB Austrian Auditorium. --- (directions http://www.facilities.upenn.edu/map.php) 4:45pm (Reception held in the CRB Lobby @ 4:30pm) Quantifying lineage divergence: the genealogical sorting index Abstract - Despite the many speciation mechanisms and the equally diverse range of species concepts, the divergence of species should be reflected in the genealogy of most loci. Ultimately gene copies at a given locus within species should share a common evolutionary history to the exclusion of gene copies within other species, that is, they will form monophyletic groups. The standard categorical phylogenetic concepts of polyphyly, paraphyly, and monophyly describe qualitative relation- ships among organismal groups (such as species) and fail to quantify the degree of genealogical divergence along a continuum. To address this problem we introduce a statistic, the genealogical sorting index (gsi), for quantifying the degree of exclusive ancestry of labeled groups on a rooted genealogy and demonstrate its application. The statistic is simple, intuitive, and easily calculated. It has a normalized range to facilitate comparisons among different groups, trees, or studies and it provides information on individual groups rather than a composite measure for all groups. It naturally handles polytomies and accommodates measures of uncertainty in phylogenetic relationships. We use coalescent simulations to explore the behavior of the gsi across a range of divergence times, with the mean value increasing to 1, the maximum value when exclusivity within a group reached monophyly. Simulations also demonstrate that the power to reject the null hypothesis of mixed genealogical ancestry increased markedly as sample size increased, and that the gsi provides a statistically more powerful measure of divergence than Fst. Applications to data from published studies demonstrated that the gsi provides a useful way to detect significant exclusivity even when groups are not monophyletic. Although we describe this statistic in the context of divergence, it is more broadly applicable to quantify and assess the significance of clustering of observations in labeled groups on any tree. John T Lonsdale PhD 407 Edgewood Drive, Exton, Pennsylvania 19341, USA Home: 610 594 9232 Cell: 484 678 9856 Fax: 315 571 9232 Visit "Edgewood" - The Lonsdale Garden at <http://www.edgewoodgardens.net/> http://www.edgewoodgardens.net/ USDA Zone 6b