CBB Seminars

Computational Biology Branch (CBB) is the research branch of the National Center for Biotechnology Information (NCBI), National Library of Medicine (NLM), National Institutes of Health (NIH).

We hold weekly seminars by CBB members each Tuesday and select Thursdays at 11 AM in the B2 Library, Building 38A. Visitors' presentations usually take place in the same room, but are scheduled on a different day of the week. If scheduling a visitor's presentation, please don't forget to book a seminar room.

To schedule a seminar, please click on the appropriate date in the calendar.

Contact Ivan Ovcharenko with questions or if you need help scheduling a seminar.

Upcoming Seminars

Michael GertzNovember 1, 2016 at 11:00
Tumor Phylogenetics Using a Ploidy Probe
“Advances in fluorescence in situ hybridization (FISH) make it feasible to detect multiple copy-number changes in hundreds of cells of solid tumors. Studies using FISH, sequencing, and other technologies have revealed substantial intra-tumor heterogeneity. The evolution of subclones in tumors may be modeled by phylogenies. Tumors often harbor aneuploid or polyploid cell populations. Using a FISH probe to estimate changes in ploidy can guide the creation of trees that model changes in ploidy and individual gene copy-number variations. We present FISHtrees 3.0, which implements a ploidy-based tree building method based on mixed integer linear programming (MILP). The ploidy-based modeling in FISHtrees includes a new formulation of the problem of merging trees for changes of a single gene into trees modeling changes in multiple genes and the ploidy. When multiple samples are collected from each patient, varying over time or tumor regions, it is useful to evaluate similarities in tumor progression among the samples. Therefore, we further implemented in FISHtrees 3.0 a new method to build consensus graphs for multiple samples. We validate FISHtrees 3.0 on a simulated data and on FISH data from paired cases of cervical primary and metastatic tumors and on paired breast ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). Tests on simulated data show improved accuracy of the ploidy-based approach relative to prior ploidyless methods. Tests on real data further demonstrate novel insights these methods offer into tumor progression processes. Trees for DCIS samples are significantly less complex than trees for paired IDC samples. Consensus graphs show substantial divergence among most paired samples from both sets. Low consensus between DCIS and IDC trees may help explain the difficulty in finding biomarkers that predict which DCIS cases are at most risk to progress to IDC.“

Shan LiNovember 3, 2016 at 11:00
Ravinder (Ravi) AbrolNovember 8, 2016 at 11:00
Mechanistic Insights into the Signaling of G Protein Coupled Receptors