Computer Virus that infects DNA?
As I understand from your post, the computer virus you are talking about is modifying database (FASTA files) in genetics. That would have a pretty bad impact on research in genetics and medicine.

If one uses such a database to synthesize/edit sequences and then introduce this DNA into a living organism, then yes the computer virus would have affected a living organism. If the sequence the computer virus has introduced is able to be transcribed into mRNA and go on infecting other cells, and eventually spread, then I guess one could say that the computer virus would have become an actual virus.

However, two things are to be considered. First, I very much doubt such a thing could go unnoticed. Second, anyone could have fun and create novel sequences. The only thing the virus does is corrupting files in a computer. The eventual existence of a man-made virus has no specific relationship with the computer virus and doing too much analogy here would stand little meaning.