Phylogenetic tree constructed using 3FTx intron II sequences with the maximum likelihood method in phylip. The intron sequences were from our BAC libraries and the GenBank database, both in the genus of Bungarus and Naja, using a colubrid (Boiga dendrophila) 3FTx as the outgroup. Numbers above branches indicate posterior probability values higher than 50%. Sequence names are labeled according the GenBank Accn. Number, followed by the species they were identified from. The sequences are classified basically based on the CDS, following the nomenclature of Fry .