Persuasive evidence against this, and in favor of the idea that they are harmful parasites that generate greater evolvability only as a side effect, comes from asexualspecies.
WSJ: Matt Ridley on Selfish DNA | Mind & Matter
2.
Instead as shown by some tiny animals, called rotifers, that have not had sex for 80 million years selfish DNA is generally purged from the genomes of asexualspecies as a nuisance.
WSJ: Matt Ridley on Selfish DNA | Mind & Matter
3.
This may explain why truly asexualspecies are rare.