COMPARISON OF THE GENOMIC SHORT REGIONS OF A VACCINE STRAIN (SA-2) AND A VIRULENT-STRAIN (CSW-1) OF INFECTIOUS LARYNGOTRACHEITIS VIRUS (GALLID HERPESVIRUS-1)

Restriction enzyme linkage maps were produced for the genomic short, r egion of the virulent infectious laryngotracheitis virus (CSW-1 strain ). After comparison with the equivalent restriction enzyme linkage map s for the infectious laryngotracheitis virus SA-2 strain (a vaccine st rain), it was determined chat the maps for the short regions of the tw o strains were identical, apart from a single section in each of the i nverted terminal repeats. Each inverted terminal repeat of the SA-2 st rain was discovered to contain 467 base pairs more DNA than the CSW-1 strain's inverted terminal repeats. This extra DNA was more precisely mapped entirely within the EcoRI fragments D and d of SA-2, which were found to form part of the SmaI fragments U and P of SA-2 and Q and b of SA-2 and to contain one SmaI restriction enzyme site.