Body site-dependent variation in the human forensic microbiome: A comparative analysis of publicly available 16S rRNA gene amplicon data.

Microbiome-based human identification has emerged as a promising complementary forensic tool. We performed a re-analysis of longitudinal Human Microbiome Project 16S rRNA gene amplicon sequencing data targeting the V3-V5 hypervariable region to assess intra and interindividual variation across multiple human body subsites. Stool microbiome exhibited the strongest evidence of individual differentiation, while salivary microbiomes demonstrated significantly greater inter-individual than intra-individual variation and high temporal stability. These findings support the potential forensic relevance of stool and saliva while highlighting the importance of body subsite selection in microbiome-based individual discrimination.