HIV-1 has many different strains with different properties, some infect brain cells, others infect macrophage cells. Such variation is extreme but is a feature of viruses with an RNA genome. Basis of Taxonomic Classification. The replication strategy of the virus depends on the nature of its genome. Some replicate in the nucleus e.g adenoviruses using cellular proteins.
Poxviruses replicate in the cytoplasm and make their own enzymes for nucleic acid replication.
These viruses have segmented genomes. Each genome segment is transcribed separately to produce monocistronic mRNAs. Translation results in the formation of a polyprotein product, which is subsequently cleaved to form the mature proteins. Complex Transcription e.g. Togaviruses. Segmented e.g. Orthomyxoviruses.