Strain Diversity of Mycobacterium tuberculosis Isolates from Pulmonary Tuberculosis Patients in Afar Pastoral Region of Ethiopia
Figure 2
Spoligoforest trees were drawn using the spoligotyping data ( isolates) and the SpolTools software ([22]; available through on http://www.emi.unsw.edu.au/spolTools) and reshaped and colored manually by the GraphViz software (http://www.graphviz.org/; [24]). Two different trees were drawn using the Fruchterman Reingold algorithm (a) and the Hierarchical Layout (b). Note that the trees illustrate each spoligotype pattern from our study by a node with area size being proportional to the total number of isolates with that specific pattern. Changes (loss of spacers) are represented by directed edges between nodes, with the arrowheads pointing to descendant spoligotypes. The heuristic used selects a single inbound edge with a maximum weight using a Zipf model. The significance of the edges is the same for Hierarchical Layout and Fruchterman Reingold trees. Solid black lines link patterns that are very similar, that is, loss of one spacer only (maximum weigh being 1.0), while dashed lines represent links of weight comprised between 0.5 and 1 and dotted lines a weight less than 0.5. In both trees, one can denote that SIT149/T3-ETH and SIT37/T3 are the biggest nodes (), followed by SIT53/T1 and SIT54/Manu2 (), SIT52/T2 () and SIT25, and SIT26/CAS1-Delhi (), which are the other predominant patterns in our study.
