Dendrogram constructed with the data from Fig. 2. The gel was analyzed by densitometry and the bands whose areas were greater than 5% of the whole lane area were used for constructing a presence–absence matrix. The similarities were calculated using the Jaccard's coefficient, and the clustering was done by using the unweighted pair group method. All calculations were done by using the MVSP (Warren W. Kovach, University College of Wales, Aberystwyth, UK) program for multivariate analysis.