Sorting Reference Genome

Certain tools expect that reference genomes are sorted in lexicographical order. These tools are often downstream of the initial mapping tools, which means that a large investment in a project has already been made, before a problem with sorting pops up in conclusion layer tools. How to avoid? Always sort your FASTA reference genome dataset at the beginning of a project. Many sources only provide sorted genomes, but double checking is your own responsibility, and super easy in Galaxy!

  1. Convert Formats -> FASTA-to-Tabular
  2. Filter and Sort -> Sort on column: c1 with flavor: Alphabetical everything in: Ascending order
  3. Convert Formats -> Tabular-to-FASTA

Note: The above sorting method is for most tools, but not all. In particular, GATK tools have a tool-specific sort order requirement.

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