Which concept relates to the impact of microbial genes on human health?

The chosen concept, symbiosis, pertains to the interactions between different organisms, particularly how microorganisms can have beneficial relationships with humans. This encompasses how the human microbiome, comprised of trillions of microbes living in and on our bodies, influences various aspects of health, such as digestion, immune function, and even mental health. Research has shown that a balanced microbiome can contribute to overall well-being, while an imbalance may lead to health issues.

In contrast, contamination refers to the presence of harmful microbes or substances, which may negatively affect health but does not describe the positive impacts of microbial genes. Isolation focuses on the separation of organisms for study or medical purposes, which doesn't directly relate to the beneficial effects of microbial genes. Decomposition involves the breakdown of organic matter by microorganisms, which is a vital ecological function but does not pertain to the interactions between these microbes and human health. Thus, symbiosis is the most relevant concept among the choices provided.