LeuRS-IN-2

Microbiome analysis characterizes microbial communities in biological or environmental samples by measuring community composition, diversity, taxonomic structure, functional potential, and associations with host or environmental phenotypes. 16S rRNA gene amplicon sequencing is commonly used for bacterial and archaeal taxonomic profiling, while shotgun metagenomics provides higher taxonomic resolution and direct functional information, including microbial genes, pathways, viruses, fungi, and antimicrobial-resistance genes when sequencing depth and host-DNA contamination are adequately controlled. Microbiome results are strongly affected by sample collection, storage, DNA extraction, contamination, sequencing method, reference database, and bioinformatic pipeline; therefore, standardized protocols, negative controls, mock communities, and transparent analysis workflows are required. Unresolved issues include low-biomass contamination, compositional-data bias, inconsistent species-level c