Phylogenetic distances based on the amino acid sequences of the L (polymerase) protein. Sequences were aligned using BLAST (http://blast.ncbi.nlm.nih.gov/Blast.cgi). Evolutionary distance is calculated by the method of Grishin {Grishin, 1995 #1138. Viruses (and Gen Bank accession numbers): MeV: measles virus (AAA75501), PVM: pneumonia virus of mice (AAW79184), HuMPV: human metapneumovirus (AHV79980), AvMPV: avian metapneumovirus (AAY82583), BRSV: bovine RSV (NP_048058), HuRSV-A: A subtype of human RSV (AEO45852), HuRSV-B: B subtype of human RSV (AEQ63655)