단일 염기 다형성 분석을 통한 미생물 출처의 법의학적 조사

Bacillus anthracis, a potential biological agent for terrorism, has been actively investigated for its underlying property and phylogenetic origin in the field of Microbial forensics. With the advancement of next generation sequencing(NGS) technology, in silico analysis becomes feasible at the whole genome sequence level, reducing the time and cost. In this paper, we suggested a methodology for identifying unknown samples form the field, which simulate real forensic evidence rather than highly purified samples, utilizing two in silico methods: k-mer analysis and whole genome single-nucleotide polymorphism(wgSNP). We performed prefix-based k-mer analysis using 964 NGS raw data obtained form the NCBI database, along with the NGS data from the unknown samples, by mapping the reads to Ames Ancestor and obtaining the consensus sequence. When analyzed together with 844 assembled sequences obtained form the NCBI database, it was determined that the unknown samples belong to the Injectional anthrax group, which was an infectious group identified among heroin users in Norway in 2000. wgSNP analysis has categorized the sample into discrete low-SNP group-Ⅰ and high-SNP group-Ⅱ, with a difference of up to 9 SNPs within each group. We observed 30 SNP positions in group-Ⅰ, which includes the unknown samples, and confirmed that the SNP of A4564 was identical to that of the unknown samples. These results demonstrate that prefix-based k-mer, and wgSNP analysis can be effectively used for the collection of microbial forensic evidence from field samples.