Molecular evolution of infectious laryngotracheitis virus (ILTV; gallid herpesvirus 1): an ancient example of the Alphaherpesviridae?

An analysis of two essential genes of infectious laryngotracheitis virus (ILTV), glycoprotein D (gD) and the immediate early gene, herpes simplex virus homologue ICP27, was performed with the equivalent gene homologues from several alphaherpesviruses. Amino acid (aa) sequence analysis revealed that these ILTV genes shared limited homology to other alphaherpesvirus equivalents and were distinct from the two other avian herpesviruses, Marek's disease virus (MDV) and herpesvirus of turkeys (HVT). Simplex and varicella group viruses are clearly separate from the avian group. The amino acid sequences of these ILTV genes will be presented with comparisons to the homologues from other alphaherpes viruses, contributing further evidence of the evolution of this group of viruses from a common progenitor and that ILTV could be an ancient example of the Alphaherpesvirinae.