ABSTRACT
The genome segment 7 of two Indian isolates of bluetongue virus (BTV) from Avikanagar (BTV-1-western India) and Hyderabad (BTV-Untyped Hyderabad-southern India) was amplified by RT-PCR using two sets of VP7 specific primers. A sequence of 1137 bp comprising the complete coding sequence of the VP7 gene from Avikanagar isolate and a 1154 bp full-length sequence from BTV-UT Hyderabad isolate were amplified. Further, restriction enzyme digestion of these full-length amplicons, using EcoRI, PstI and TaqI revealed that genome segment 7 from both isolates were different from each other by absence of any EcoRI site in the BTV-UT Hyderabad isolate. There were also variations in the number and position of restriction sites for TaqI enzyme in these two isolates. Taql has two sites in the Avikanagar isolate whereas four sites in BTV-UT Hyderabad. The restriction digestion fragments obtained after PstI digestion were differentiated on the basis of their distinct sizes in both isolates. Comparison of their in silico restriction profiles with that of other isolates from different countries revealed that the two Indian isolates belonging to different parts of India had variations in their VP7 gene which was also distinguishable from at least some isolates from Australia and South Africa. Hence the restriction enzyme (RE) based analysis might be a useful tool in determining the genetic diversity in genome segment 7 and also for tracing their evolutionary relationships.