Figure 1.

Relational databases help link metadata from multi-step experiments. Relational databases are similar to Russian dolls, nested in a particular order. They allow researchers to capture metadata at every experimental step. For example, linking sequencing data to the cDNA library, tissue (lung biopsy) and animal (non-human primate, NHP) from which it came from. The metadata for the two different sequencing files helps future users realize that the main difference between the sequenced samples is that they come from different animals that vary by sex and treatments, despite being from the same species.