A statistical test for the detection of inhomogeneity in metagenomic samples

In this study, we provide a non-parametric statistical "triangulation test" for the detection of inhomogeneity in metagenomic samples. The test requires biological replicates from one sample and additionally multiple technical replicates from each biological replicate. The test is based on a three-way computational comparisons of samples. We collected three biological replicates from different locations of a human stool sample (A, B, and C) to illustrate the application of the test. Each biological replicate is furthermore represented by three technical replicates (A1, A2, A3, B1, B2, B3, C1, C2, and C3). The triangulation test indicates that the microbial composition of human stool is not homogenous on the centimeter scale in our sample. The test is implemented in MEGAN6.