Viral vectors take advantage of natural viral behavior. Viruses evolutionarily excel at penetrating cellular membranes and utilizing host nucleic acid replication machinery to read and transcribe viral genomes. Viral vectors are designed to utilize these affinities in order to deliver the target gene to the nucleus for integration, expression, and transcription. However, viral vectors typically have their replication and pathogenic capabilities disabled, so as to not harm or kill the transduced cell.