How to find premature stop codons

Question

[the_cowa]

Is there any way to find premature stop (mutation) from the aligned fasta file?

[rpolicastro]

You need to provide some background for what you are doing, such as what is that fasta file, and how was it generated? It also would help to provide a few sequences from the fasta file so we know what we are looking at, as well as allow for a reproducible example.