Krauter Lab Research

Human-Microbiome interactions

We study interactions between humans and their associated microbes primarily using genetic approaches. Based on our data as well as that of others, we know that some aspects of the microbiomes of the mouth and the gut are influenced by the genome of the human host. On the right top is a figure that shows “average” similarity of microbiome diversity between monozygotic twin pairs (MZs share 100% of their alleles), dizygotic twin pairs (DZ share average 50% of their alleles) and unrelated individuals that share about 10% of their alleles. The lower the “Bray Curtis” value, the more similar are the twins.  You can see that MZs are more similar than the other pairwise comparisons.  This can ONLY be explained by heritability - i.e. human genes determine this.  

To find out the mechanism of this hertitability, we are focused on determining which human genes are responsible for this.  We have carried out a slightly underpowered initial genetic mapping study shown in the bottom.  This Genome Wide Association Study (GWAS) was done on the oral microbes found in about 750 unrelated individuals. In this sort of “Manhattan Plot” the peakscorrespond to the probability that individual mapped single nucleotide polymorphisms are associated with a heritable microbiome trait (in this case Streptococcus abundance).  While no SNPs achieved true genome-wide statistical significance (the red line), 3 or 4 peaks were considered “suggestively significant”.  Work in the lab is currently focused on increasing the size of the study population by a factor of 12X which we estimate will easily allow a statistically significant result.