Phylogentic tree of 53 bHLH superfamily members and one of their closest homologues. The amino acid sequences were aligned in MAFFT and converted to a nexus file in BioEdit. The nexus file was analyzed under Bayesian optimality criterion using MrBayes version 3.1.2. The summary tree obtained by keeping burnin at 2,500,000 generations and probabilities is shown. Phylogenetic analysis classified 53 bHLH genes into ten families; PAS, HES, Myc/USF, Hand, Mesp, Shout, p48, NeuroD/ Neurogenin, Atonal and AS-C. Ten proteins such as TcHLH106, TcBigmax, TcAP-4, TcHLH3B, TcHLH4C, TcNautilus, TcExtramacrochaete (Emc), TcDaughterless, TcParaxis and TcMitf did not fall into any of these ten families and are grouped under miscellaneous family.