Estimating dN/dS directly from BAM/SAM files

Question

[DR]

Hello everybody!

I am working with metagenome assemblies and I am making gene prediction on them. The next step I would like to carry out is to map my reads into those predicted genes and to estimate dN/dS based on these mapping files (BAM/SAM) Does someone know if there is any pre-existing tool performing this?

Thank you very much for the help!