This was the first known enzyme to take its instructions from a DNA copy.

It means having two RNA genome per virion but giving rise to only one DNA copy in infected cells.

RNA is used as the target and a DNA copy is made.

The DNA copy is then transcribed into RNA and amplified.

The disadvantage is that there is no 'back-up' DNA copy.

The fact that DNA copy number variation is a widespread and common phenomenon among humans was first uncovered following the completion of the human genome project.

Without a bacterial host it can't reproduce, but neither can DNA copy itself without a cell's chemical machinery.

The DNA copy is then inserted into the genome in a new position.

Secondly, it could bind to the DNA copy of the viral RNA.

A provirus does not directly make new DNA copies of itself while integrated into a host genome in this way.