The human gut microbiome is central to health, yet its long-term stability and intra-individual dynamics remain insufficiently understood. Most existing studies rely on cross-sectional data, limiting insight into how microbial communities persist, fluctuate, and evolve within individuals over time. In particular, little is known about genome-level stability, strain variation, and the persistence of microbial functional capacity in healthy hosts. This project aims to investigate longitudinal, intra-individual dynamics of the gut microbiome with a focus on genome-resolved microbial populations, their functional potential, and their evolutionary relationships. By examining microbial communities at high resolution over time, the study will identify stable and variable components of the microbiome and determine how functional capabilities are maintained despite taxonomic changes. The role of bacteriophages will also be considered as potential modulators of microbial stability and community structure. A central goal is to link microbial persistence with functional consistency, addressing whether stable ecosystem function is maintained through stable genomes or through functional redundancy among shifting microbial populations. The project will also explore strain-level diversity and evolutionary signals within dominant gut microbes to understand mechanisms of persistence and adaptation in the gut environment. Overall, this study will provide a detailed, genome-level perspective on gut microbiome stability and change within individuals. It will advance understanding of how microbial communities maintain functional resilience over time and establish a framework for future research on microbiome dynamics in health and disease.