Adding a tag
Bérénice Batut
Wolfgang Maier
Helena Rasche
Saskia Hiltemann
Anton Nekrutenko
hall-of-fameAdd Contributions!Datasets can be tagged. This simplifies the tracking of datasets across the Galaxy interface. Tags can contain any combination of letters or numbers but cannot contain spaces.
To tag a dataset:
- Click on the dataset to expand it
- Click on Add Tags galaxy-tags
- Add tag text. Tags starting with
#will be automatically propagated to the outputs of tools using this dataset (see below). - Press Enter
- Check that the tag appears below the dataset name
Tags beginning with # are special!
They are called Name tags. The unique feature of these tags is that they propagate: if a dataset is labelled with a name tag, all derivatives (children) of this dataset will automatically inherit this tag (see below). The figure below explains why this is so useful. Consider the following analysis (numbers in parenthesis correspond to dataset numbers in the figure below):
- a set of forward and reverse reads (datasets 1 and 2) is mapped against a reference using Bowtie2 generating dataset 3;
- dataset 3 is used to calculate read coverage using BedTools Genome Coverage separately for
+and-strands. This generates two datasets (4 and 5 for plus and minus, respectively); - datasets 4 and 5 are used as inputs to Macs2 broadCall datasets generating datasets 6 and 8;
- datasets 6 and 8 are intersected with coordinates of genes (dataset 9) using BedTools Intersect generating datasets 10 and 11.
Now consider that this analysis is done without name tags. This is shown on the left side of the figure. It is hard to trace which datasets contain “plus” data versus “minus” data. For example, does dataset 10 contain “plus” data or “minus” data? Probably “minus” but are you sure? In the case of a small history like the one shown here, it is possible to trace this manually but as the size of a history grows it will become very challenging.
The right side of the figure shows exactly the same analysis, but using name tags. When the analysis was conducted datasets 4 and 5 were tagged with #plus and #minus, respectively. When they were used as inputs to Macs2 resulting datasets 6 and 8 automatically inherited them and so on… As a result it is straightforward to trace both branches (plus and minus) of this analysis.
More information is in a dedicated #nametag tutorial.