Dendrogram of a hierarchical clustering (UPGMA) with the height of the nodes (adapted from bacterial 5S rRNA sequence data[1]).Dendrogram output for hierarchical clustering of marine provinces using presence / absence of sponge species.[2]A dendrogram of theTree of Life. This phylogenetic tree is adapted from Woese et al. rRNA analysis.[3] The vertical line at bottom represents thelast universal common ancestor (LUCA).Heatmap ofRNA-Seq data showing two dendrograms in the left and top margins.
Adendrogram is adiagram representing atree. This diagrammatic representation is frequently used in different contexts:
inhierarchical clustering, it illustrates the arrangement of the clusters produced by the corresponding analyses.[4]
The namedendrogram derives from the twoancient greek wordsδένδρον (déndron), meaning "tree", andγράμμα (grámma), meaning "drawing, mathematical figure".[7][8]
For a clustering example, suppose that five taxa ( to) have been clustered byUPGMA based on a matrix ofgenetic distances. Thehierarchical clustering dendrogram would show a column of five nodes representing the initial data (here individual taxa), and the remaining nodes represent the clusters to which the data belong, with the arrows representing the distance (dissimilarity). The distance between merged clusters is monotone, increasing with the level of the merger: the height of each node in the plot is proportional to the value of the intergroup dissimilarity between its two daughters (the nodes on the right representing individual observations all plotted at zero height).
Iris dendrogram - Example of using a dendrogram to visualize the 3 clusters fromhierarchical clustering using the "complete" method vs the real species category (usingR).
