What tells us that this new form of H1N1 is swine flu and not regular old human flu or avian flu? If we had a lab, we might use antibodies, but when you're a digital biologist, you use a computer. Activity 4. Picking influenza sequences and comparing them with phylogenetic trees We can get the genome sequences, piece by piece, as I described in earlier, but the NCBI has other tools that are useful, too.