Ka/Ks ratio

[Michael Steiper]

Hi-

I am trying to detect positive natural selection in a group of sequences
using Ka/Ks comparisons.  The problem is that my number of Ks is zero in
one of my branches.  With this zero in the denominator, I get undefined
answers and strange results using the PAML program.

Has anyone seen a case like this?  It seems like someone must have
encountered this before, and I'd like to see how it was handled.  Any
other ideas might be helpful, too.

THanks,

Michael Steiper

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