The human microbiome, although representing 10 times the number of actual human cells, only weights 200g.
The Human Microbiome Project (HMP), founded in 2008, explores the human microbiome in depth with a budget of $115 million.
HMP estimates that more than 10,000 species populate the human body.
A recent body of work published in June 2012 mapped the human microbiome. With a limited number of samples (242 volunteers and 5,000 DNA samples), teams generated 3.5 terabases of data (a terabase is one trillion subunits of DNA).