Pararetroviruses are, naturally,
viruses. But they are also
retroelements. This means that they can produce
reverse transcriptase. However, unlike
retroviruses, they cannot insert themselves into the host's
chromosome.
Pararetroviruses are double stranded or partially double stranded circular DNA viruses. Unlike other double-stranded DNA viruses, though, they replicate using only one strand. The strand is replicated in the regular manner, to yield the complimentary strand. And then it is transcribed to RNA and reverse transcribed to DNA to yield the original strand.
There are 3 types of pararetroviruses: