a universe of us

NYTimes | We think of ourselves as individuals — perhaps, in philosophical moments, as the merger of body and soul. Most of us are barely aware of the estimated 10 trillion individual cells that make up the human body or of the 100 trillion or more bacteria that live collaboratively and benignly within and upon us. Whatever else we are, we are also a complex ecosystem, a habitat.

Scientists now have discovered another realm within our habitat — the virome, a large community of viruses. These are not the viruses that make us sick. These are an integral part of the microbiotic universe that makes us healthy.

In a recent paper in Nature, a team led by Jeffrey Gordon, a microbiologist at Washington University, reports that each of us has, so to speak, a viral identity — a pattern of viral DNA that is highly stable and highly distinct, even among closely related humans. This is unlike bacterial communities, which tend to evolve over time and to be similar among family members.

This discovery is part of a rapidly growing interest in the microbiome — an effort to understand the diversity and complexity of the trillions of organisms living within each of us. The basic exploratory technique is broad-scale DNA sequencing of the genetic contents of the human gut. The result is a significantly different view of who we are.

We are not just the expression of an individual human genome. We are, as Dr. Gordon writes, “a genetic landscape,” a collective of genomes of hundreds of different species all working together — in ways that leave our minds mysteriously free to focus on getting our bodies to the office and wondering what’s for lunch.