Biological/technical replicates and sub-processes
In the following scenario we focus on annotating the origin and relationship between biological/technical replicates and managing sub-processes within an assay. We start with the five samples (S1, S2, …, S5), originating from the isa.study.xlsx file. We want to perform a transcriptomics analysis but before that we have to extract RNA from our samples. Some processes and lab procedures cannot be described coherently in one isa table, even though they are part of the same assay. In such case, you can split subprocesses into different sheets of the same isa table. For example, here the extraction of RNA is described in the first sheet with an output being the RNA samples (rna_sample1, …). Then on the next sheet is the table representing the sequencing itself. As you can see, the input becomes the output from the previous sheet, thus, indicating the processes are sequential. In the same manner, samples and processes are being connected across studies and assays within an ARC. While performing the RNA sequencing, three technical replicates per sample are generated (Characteristic [technical replicate]). However, each replicate results in its own data file.
