The HIV replication cycle in cells
Retroviruses are distinguished from other viruses by two characteristic steps in the replication cycle. The viral RNA genome is copied into DNA by the process of reverse transcription. The DNA copy is then integrated into a chromosome of the host cell. There are many examples of reverse transcription in biology outside of the retroviruses, and replication of many transposons involves integration reactions quite similar to retroviral integration   The combination of reverse transcription and obligate integration, however, defines the retroviruses.