Classification and molecular organization of satellites elucidated by phylogenetic network analysis - examples from Triturus salamanders and Palorus beetles

A phylogenetic network of 244 satellite DNA sequences across five species of aquatic salamanders (genus Triturus) revealed four types of satellite DNAs in a 'p'-shaped 1-2*-3-4-2* arrangement. Analysis of dimer and trimer DNA sequences revealed a prevalence of homosequential (e.g. 1-1, 2-2) and particular (1-4 and 2-3) heterosequential repeat motifs. Genetic diversity across types and species phylogeny indicated that type 1 and type 4 are derived from types 2 and 3. Support was also found for alternating motifs in Palorus flour beetle tandem repeats. The results were statistically significant, whether or not the underlying satellite DNA phylogenies were robust under bootstrap analysis.