Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The multi-alignment of residue substitutions associated with virus tropism. (a) IBV isolates closely related to 4/91 genotype showed mutations at positions 38, 43, 63, and 69 in comparison with their parental origin (GI-13). (b) IBV isolates closely related to IS/720/99 showed mutations at positions 38, 63, and 69 in comparison with their parental origin (GI-23 lineage).
