🧬CroCoDeEL is a new tool for detecting cross-sample contamination in metagenomic data.🐊🦠 The idea behind CroCoDeEL is simple and elegant. Imagine different cocktails poured into a row of glasses. If a drop from a Bloody Mary splashes into a Moscow Mule, the second glass gets a small, diluted but still recognizable trace of the first cocktail. CroCoDeEL looks for these suspicious “drops” in metagenomic profiles. In many ways, modern bioinformatics is the art of quality control. Samples from relatives — for example, a mother and her child — may naturally end up in neighboring wells on a plate. In that case, cross-contamination can be mistaken for microbiome heritability. The authors applied the tool to published datasets and found previously unnoticed contamination. In infant microbiome studies, some bacteria interpreted as possible mother-to-child transmission were likely contamination from maternal samples. This matters because such findings affect how we understand early microbiome development. Another example is the TwinsUK cohort, where CroCoDeEL identified 202 contaminated samples. Many shared the same sources, had higher species richness, and were more similar to each other than expected. nature.com/articles/s41467-0… #Microbiome #Metagenomics #Contamination #QC