Objective To perform a genome-wide association study of rubella virus vaccine strain BRD-Ⅱ, so as to fully grasp the sequence characteristics of this genome.

Methods Second-generation sequencing method was used to conduct the whole-genome sequencing on the vaccine strain BRD-Ⅱ, and the affinity tree of this genome with some vaccine strains and wild-type rubella virus strains was analyzed using the maximum likelihood method. The average genetic distance of nucleic acid sequence of each vaccine strain protein was determined. And homology comparison of structural proteins of each rubella vaccine strain, plus the comparison between this genome with the AY258323.1 genome sequence, were conducted to analyze the homology of E1 protein between the wild-type rubella virus reference strain and vaccine strain BRD-Ⅱ.

Results The sequencing results showed that the BRD-Ⅱ strain was a single-molecule single-stranded positive-strand ribonucleic acid (RNA), composed of 9 778 nucleotides, with a GC content of 69.35 %. The C protein was composed of 300 amino acids, the E2 glycoprotein was composed of 282 amino acids, and the E1 glycoprotein was composed of 481 amino acids. The results of preliminary analysis showed that the average genetic distances of nucleic acid sequences were 0.066 700 for the P150 protein, 0.061 933 for the P90 protein, 0.057 850 for the C protein, 0.068 167 for the E2 protein, and 0.068 833 for the E1 protein, respectively. The amino acid sequences in the E2 protein and E1 protein regions of the two BRD-Ⅱ strains did not change, confirming the conserved regions of the E1 protein by comparison.

Conclusion The sequence characteristics of the genome are clarified, which have laid a broad foundation for the subsequent detection of the genetic stability of the main antigen genes.