RICH SOIL GENE POOL. “This indicates that the metagenomes from the two micro-ecosystem samples sequenced here are more than 30-fold larger than the human genome, and more than 20 000-fold that of an average bacterial genome. Given one gene per kb, our data indicate that there are about 100 million genes in the soil metagenome.”
http://onlinelibrary.wiley.com/doi/10.1111/jam.12035/full