Copyright information:Taken from "Genetic and phylogenetic evolution of HIV-1 in a low subtype heterogeneity epidemic: the Italian example"http://www.retrovirology.com/content/4/1/34Retrovirology 2007;4():34-34.Published online 21 May 2007PMCID:PMC1892567.ence sequences of all Group M subtypes, in order to generate the phylogenetic tree by the neighbor-joining method. The Bindicates the "Italian branch" of the tree, which includes three major clusters B– B. The reliability has been estimated from 1'000 bootstrap replicates. For editorial convenience, only the percentage value for the Italian Branch has been shown. All other values are > 90%.