Microbiome Monday: The Microbiome of the World

On Exhibit posts

The Healthy Human Microbiome project (HHMP) is wrapping up summer sampling at the Museum this month and entering its next phase of data generation and analysis. 

In today's Microbiome Monday, Dr. Paul Planet of Children's Hospital in Philadelphia (CHOP), Dr. Jeffrey Shaman of Columbia University's Mailman School of Public Health, and Museum Curator Rob DeSalle share some initial findings. (For more on this project, revisit some of our past Microbiome Monday posts).

So far this summer, more than 1,100 visitors to the Museum have participated in the Healthy Human Microbiome Project (HHMP) in the Museum's Sackler Educational Laboratory (sampling continues on weekends through July 31). Participants' microbiomes were sampled through swabbing at four locations on the body—the nasal passage, tongue, and left and right hands. During the initial sampling period, individuals from more than 50 countries—detailed on the map below—contributed samples of their microbial makeup to the HHMP.

A map showing where HHMP participants hailed from. Countries in blue contributed the most, followed by green, yellow, orange and red.

© HHMP


The geographic breadth of sampling over a short period of time is impressive, and it's the reason the HHMP was hosted at the Museum—an institution with weekly visits by tens of thousands of people from all over the world.  

In addition to providing samples of swabs, participants also answered more than 20 demographic questions about topics like their country of origin, travel habits, and general health. Those answers can be linked to the microbiome data that's now being generated by DNA sequencing, which has the potential to help scientists understand the impact of certain microbes on a variety of fronts.

Participants in the HHMP anonymously answered questions to provide context for microbial data. 

© HHMP


While it promises to be useful for years to come, the HHMP has already produced its first small data set from 44 samples of nasal passage and tongue swabs selected and analyzed using DNA sequencing. You can see some of the data visualized in the graph below. It's a principal components graph—the tighter the cluster, the more similar the microbiomes—and it reveals a couple of interesting facts. 

A graph showing that individuals around the world have similar tongue microbiomes, but varying populations in their nostrils (nares).

© HHMP


First, you can see that tongue microbiomes (blue) are clustered tightly, while the microbiomes of nasal passages , or nares (red), are widely scattered. Note also that there is no mixing of tongue and nasal passage microbiomes.

While it is very important to be cautious about not overselling microbiome data in general and preliminary data specifically, we see one very interesting early result: the microbes on participants’ tongues are more similar to each other than an individual’s tongue microbes are to the microbes in their own nose. The implications are fascinating and represent just the tip of the iceberg for this growing set of data. 

As the study expands in the next two years, more samples will be taken over the next year from Museum visitors, eventually increasing the total sample size to over 6,000 individuals. In addition, all of the samples will be sequenced for the four body locations. The result will be one of the most comprehensive microbiome studies ever conducted, which promises to produce a data set that will keep researchers busy for years to come.

For more about the human microbiome, visit The Secret World Inside You, open now through August 7.