Identification and mutation of the P48 gene in M. bovis strain Hubei-1. a: Identification of P48 gene in M. bovis strain HB-1, using primer MB-F and MB-R primers. An amplified product of 1,341 bp as expected was obtained. b: Mutation of the bases on 192, 648, 1,275, 1,317 in the first PCR run. Four overlapping fragments, as expected, were 223 bp, 489 bp, 663 bp and 89 bp. d: Mutation of the base on 692 in the third PCR run, two overlapping fragments, 729 bp and 671 bp as expected were obtained. c and e: full length product obtained using purified fragments as template (MB-a and Mb-d’ primer) in the second and fourth PCR runs, respectively.