DAVID,Database for Annotation, Visualization and Integrated Discovery,DAVID provides a comprehensive set of functional annotation tools for investigators to understand biological meaning behind large list of genes,Identify enriched biological themes, particularly GO terms Discover enriched functional-related gene groups Cluster redundant annotation terms Visualize genes on BioCarta default = 4): the minimum number of annotation terms overlapped between two genes in order to be qualified for kappa calculation. Similarity Threshold (any value between 0 to 1; Default = 0.35): the minimum kappa value to be considered biological significant. Initial Group Members (any value =2; default = 4): the minimum gene number in a seeding group, which affects the minimum size of each functional group in the final. Final Group Members (any value =2; default = 4): the minimum gene number in one final group after “cleanup” procedure. Multi-linkage Threshold (any value between 0% to 100%; default = 50%): It controls how seeding groups merge each other, i.e. two groups sharing the same gene members over the percentage will become one group. The higher percentage, in general, gives sharper separation i.e. it generates more final functional groups with more tightly associated genes in each group. In addition, changing the parameter does not contribute extra genes into unclustered group.,