Microbial 'omics


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anvi-get-pn-ps-ratio [program]

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Table of Contents

Can provide

pn-ps-data

Can consume

contigs-db variability-profile-txt

Usage

This program calculates the pN/pS ratio for each gene in a contigs-db and outputs it as a pn-ps-data artifact.

What is the pN/pS ratio?

The pN/pS ratio (first described in Schloissnig et al. 2012) is the ratio of 2 rates: the rates of non-synonymous (pN) and synonymous (pS) polymorphism. It is analogous to dN/dS, which is the ratio of rates between non-synonymous (dN) and synonymous substitutions between 2 strains/species. We calculate pN/pS from allele frequency obtained through SCVs and SAAVs (see publication in preparation) for exact implementation details.

Neat. How do I use this program?

Firstly, you’ll need to run anvi-gen-variability-profile using the flag --engine CDN to get a variability-profile-txt for SCVs (single codon variants), which we’ll name SCVs.txt in this example.

Then you can run this program like so:

anvi-script-calculate-pn-ps-ratio -V SCVs.txt \ -c contigs-db \ -o output_dir

A pN/pS value is calculated for each (gene, sample) combo. This will result in a directory called output_dir that contains several tables that describe each of your genes. See pn-ps-data for more information.

Other parameters

This program has some default filtering choices that you should pay mind to. You can tune these filter options with the following variables:

  • The minimum departure from consensus for a variable position (--min-departure-from-consensus).
  • The minimum departure from reference for a variable position (--min-departure-from-reference).
  • The minimum number of SCVs in a grouping (--minimum-num-variants).
  • The minimum coverage at a variable position (--min-coverage).

Edit this file to update this information.

Additional Resources

Are you aware of resources that may help users better understand the utility of this program? Please feel free to edit this file on GitHub. If you are not sure how to do that, find the __resources__ tag in this file to see an example.