How to find fixed mutations between populations

Question

[Yongjie Zhang]

Hi All,

I have a multiple sequence alignment in fasta format, where the sequences were divided into two groups. I want to find fixed mutations between groups, i.e., nucleotide sites at which all of the sequences in one group are different from all of the sequences in the second group. Only those fixed sites should be displayed and saved as a new file.

Do you know what application could fulfill my task easily?

Thanks,

Yongjie