How one scientist’s gut microbes changed over a year

Daily sampling allowed Lawrence David to track fluctuations in his microbiome

graph of microbe abundance

MICROBIAL ROLLER COASTER  Computational biologist Lawrence David tracked changes in the friendly bacteria in his mouth and intestines by analyzing daily saliva and fecal samples. The data (close-up above; see full graphs in story) show the ebbs and flows of his microbiome over the course of a year.

All: L.A. David et al/Genome Biology 2014

Where you live and what you eat can rapidly affect the types of friendly bacteria inhabiting your body. To see how the microbes that inhabit the mouth and intestines change over time, Duke University computational biologist Lawrence David zealously chronicled his microbiome for an entire year. (For more on David and this experiment, see “Lawrence David’s gut check gets personal.”)

A stream plot (below, top graph) shows the ebb and flow of phyla of bacteria in his gut over time. The thickness of each stream indicates a bacterial group’s relative abundance in daily fecal samples. 

David peered closer at the data in a horizon plot (above, bottom graph; colored squares at left indicate the phylum of the bacteria represented in each row). He first determined each type of bacteria’s normal abundance in his gut, then calculated how much they differed from the median abundance. Warmer colors (red, orange, yellow) indicate that bacteria in that group increased in abundance, and cooler colors (blue, green) indicate a decrease in abundance. Living abroad from day 71 to day 122 had a dramatic — but short-lived — effect on David’s microbiome. 

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

More Stories from Science News on Life

From the Nature Index

Paid Content