Viral diversity in the human microbiome

The number of viral particles on Earth outnumber other microbes by an order of magnitude, and the same holds true in the human microbiome. The human-associated virome is typically dominated by phage, which have historically been difficult to identify via either culture or metagenomics. With the launch of the Human Virome Program, a range of new computational and experimental methods are being developed and applied to large populations to establish an improved baseline for virome diversity. I will discuss the HVP as a program, as well as an early look at improved methods for viral profiling from metagenomes and metatranscriptomes, along with their application to identify ecological and individual viral associations with conditions including the inflammatory bowel diseases and colorectal cancer.