Relationship of fungal G$\alpha$ amino acid sequences of subgroups I and III whose members Tga1 and Tga3 were shown to be essential for mycoparasitism of T. atroviride. In addition, the fourth G$\alpha$ subunit only present in U. maydis (Gpa4) and A. oryzae (GaoC) were included and are indicated as subgroup IV. The tree was generated using Neighbor-Joining algorithm subsequent to CLUSTALX alignment. The fourth G$\alpha$ subunit of U. maydis Gpa4 has been defined as outgroup. Abbreviations used: Ao: Aspergillus oryzae; Mg: Magnaporthe grisea; Nc: Neurospora crassa; Ta: Trichoderma atroviride; Tr: Trichoderma reesei; Tv: Trichoderma virens; Um: Ustilago maydis.