Revised estimates for number of bacterial and human cells “in a human body”

This (accurate) information is what every genomicist and molecular biologist needs to know, … in order to be the hit of cocktail party conversations.  Reported values in the literature on the number of cells in the body differ by orders of magnitude and are very seldom supported by any measurements or calculations.

In the attached mini-Review, authors integrate the most up-to-date information on the number of human and bacterial cells in the body. They estimated the total number of bugs in “the 70-kg reference man to be 3.8 x 1013 bacterial cells. For human cells, they identified the dominant role of the hematopoietic lineage to the total count (~90%) and revised past estimates to 3.0 x 1013 human cells. This analysis also updates the widely-cited erroneous 10:1 ratio (“10-times more bacterial than human cells)––showing that the number of bacteria in the body is actually of the same order (only 1.27X larger) as the number of human cells, and the bacterial total mass is about 0.2 kg.

PLoS Biol  2o16; 14: e1002533

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