The Kallisto Effect

retrovirus

Any of a family of viruses (Retroviridae) containing the genetic material RNA rather than the more usual DNA. For the virus to express itself and multiply within an infected cell, its RNA must be
converted to DNA. It does this by using a built-in enzyme known as reverse transcriptase (since the transfer of genetic information from DNA to RNA is known as transcription, and retroviruses
do the reverse of this). Retroviruses include those causing AIDS and some forms of leukaemia. See immunity. Retroviruses are used as vectors in  genetic engineering, but they cannot be used to target specific sites on the chromosome. Instead they incorporate their genes at random sites.